The building and construction sector accounts for a significant proportion of current anthropogenic CO₂ emissions. Reducing the carbon footprint of building materials is difficult because some process-related CO₂ emissions cannot be avoided. While the industry is developing methods to reduce its emissions by capturing CO₂ from flue gas streams, this study investigates an alternative mechanism to reduce the carbon footprint of building materials, namely the incorporation of olivine into building materials such as façade plaster. Olivine is susceptible to weathering and reacts with CO₂ to form magnesium carbonate and silica.

In collaboration with the company Knauf Gips KG, an outdoor test facility will be built to monitor the mineralogical changes in olivine façade plaster under natural weathering conditions over a period of 18 months. In parallel, laboratory experiments will be carried out to accelerate the weathering process by continuous artificial weathering of the plaster samples. Fluids will be regularly sampled and analysed to detect potential environmental hazards, such as the release of nickel and chromium into the environment. All plaster samples will be analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to identify mineralogical and structural changes during the experiments. The extent of CO₂ mineralisation will be assessed based on mass balance calculations with the experimental reactants and their products. A sustainability assessment of the whole value chain will be carried out to determine whether olivine in building materials can effectively contribute to offsetting the CO₂ emissions of the construction industry.

Marine sediments may act as a sink for carbon. Substrate and electron donor availabilities, sedimentology, as well as biological activity may influence the carbon cycling, impacting the release of TA and DIC. The North Sea is a highly dynamic system with shallow tidal areas and fresh water tributaries delivering nutrients and dissolved carbon. For the southern part, benthic DIC sources have been identified [1], with tidal areas being further hot spots [2], some being impacted by submarine fresh water discharge [3]. The Skagerrak provides the unique opportunity of studying benthic DIC production under the impact of different dominant electron acceptors [4]. Potential transformation of carbonates may impact release of TA and DIC.

Here, we investigated the role of different sediments from the North Sea, including tidal areas, for their DIC source function and carbon storage capacity. Water column, pore water, and sediment samples were investigated to understand the processes controlling the benthic production and release of TA and DIC. The carbon isotope composition of dissolved and solid phases were investigated to understand the specific biogeochemical processes dominating benthic mineralization and carbonate dissolution.

[1] Burt et al. (2016) Limnol. Oceanogr. 61, 666-683. [2] Schwichtenberg et al. (2020) Biogeosciences, 17, 4223-4245. [3] Winde V. et al. (2014) J. Mar. Sys. 129, 394-402. [4] Canfield D.E. et al. (1993) Geochim Cosmochim Acta 57, 3867-2883.

The investigations are carried out within the BMBF project COOLSTYLE/CARBOSTORE. The Sylt part also contributes to the DFG project KiSNet, and investigations are further supported by Leibniz IOW.

The application of finely ground silicate minerals to croplands and forests, with the aim of enhancing the rate of natural CO₂ consuming weathering reactions, is receiving attention as a part of climate change mitigation strategies. Yet considerable uncertainty surrounds the quantification of CO₂ removal associated with Enhanced Weathering, and its potential efficacy remains undemonstrated outside of the laboratory. Here, I discuss how the geochemical insights garnered from decades of natural weathering studies provide a pathway towards a strategy for ‘Monitoring, Reporting and Verification’ of CO₂ sequestration. These natural weathering studies have also produced an understanding of what limits silicate weathering in different settings, which can be used to shed light on how deployment strategies, and specifically application sites, can be optimised.

Thermokarst lagoons form at the terrestrial-marine interface when thermokarst lakes, hotspots for Arctic methane emissions, erode onto the Arctic shelf. Thermokarst lagoons are dynamic environments with seasonal ice build-up and potential alternations between freshwater and marine discharge. Aiming to understand how microbial methane cycling changes along thermokarst lake to lagoon transitions we have investigated the sediment geochemistry and microbiota of the Polar Fox lagoon, a thermokarst lagoon in north-eastern Siberia, relative to that of two adjacent thermokarst lakes. In-situ methane concentrations, methane-carbon isotopic signatures, analysis of amplicon sequencing variants (ASVs), metagenomics, and pore-water geochemistry point towards efficient communities of anaerobic methane oxidizers (AOM) in a sulfate-methane transition zone 2-3 meters below the sediment surface of the lagoon. The lagoon’s in-situ methane concentration in the sulfate zone was only 0.4 – 5% that of the deeper sediment and of the two adjacent thermokarst lakes which have no connection to the Arctic Ocean. In the lakes, methane concentrations reached values up to 2.2 µmol per gram pointing towards oversaturation with methane in the sediment. Based on the analysis of general microbiome composition, we suggest that deterministic process triggered a substantial overall shift of microbial assemblages and a loss in spatial dissimilarity and diversity. Our study shows that thermokarst lake to lagoon transitions are associated with the formation of novel sediment microbiomes and that Arctic thermokarst lagoons can host efficient AOM communities with the potential to substantially mitigate methane concentrations in coastal thermokarst sediments.

Global warming is the greatest threat for humankind today. Despite all efforts to reduce CO₂ emissions, the undertaken measures are not sufficient to stop the temperature rise. One recently proposed and promising approach to actively remove CO₂ from the atmosphere is carbon dioxide removal through marine alkalinity enhancement. This technique increase the natural CO₂ uptake capacity of seawater through weathering of fine-grained alkaline minerals in marine environments. Even through this method has been extensively tested and verified by numerical models, field experiments scaling the CO₂ uptake under natural conditions and assessing the impact on the environment and biota are still lacking. To bridge this gap of knowledge a monitored 2-year in-situ experiment was established in September 2022 at the Ria Formosa Coastal Lagoon, southern Portugal.

The experiment was installed in the pioneer vegetation zone of the saltmarsh with three replicate plots. Each plot contain deployments of coarse olivine, fine olivine, coarse basalt and fine basalt and an unchanged area as control. Supernatant and porewater from each treatment are analysed monthly for temperature, salinity, oxygen concentration, pH, total alkalinity, nutrients, and trace metals. Sediment samples are analysed quarterly for faunal and floral composition to evaluate the impact on the biota.

The first months of the experiment showed an increase in total alkalinity in the supernatant and porewater of the treatments. Other environmental parameters remained stable among the different treatments and control. The total alkalinity decreased through time although remained on higher levels as compared to the natural background level.

Acknowledgment. Research supported by the Portuguese Science Foundation, with the projects PTDC/CTA-CLI/1065/2021, UID/00350/2020CIMA and contracts DL57/2016/CP1361/CT0009.

CO₂ neutrality by 2045 requires increasing the currently worldwide achieved CO₂ storage volume (40 Mt/y) to the order of tens of Gt/y. With current storage techniques, CO₂ often remains in the gaseous phase, thus, free to spread underground risking unwanted leakage in the distant future. As an alternative, the mineralization of CO₂ in basalts, where the vast majority (>90%) of the carbon is mineralized and fixed in carbonates within two years, offers a permanent safe storage as a solid (e.g. CarbFix, Iceland).
The international joint project PERBAS (ACT4) with partners from Norway, USA and India aims to pave the way for the commercialization of large-scale, permanent CO₂ sequestration into marine basalt complexes off the coast of Norway and India. The project seeks solutions for reservoir selection, CO₂ transport, injection and monitoring. PERBAS will investigate the feasibility of supercritical CO₂ injection, using water in the pore space, in order to avoid the requirement to inject 20 t of water for 1 t of CO₂. This would have the additional advantage that supercritical CO₂ would be associated with a free gas phase, which allows the application of geophysical remote sensing for monitoring thereby reducing the number of monitoring wells required.
Within the German sub-project CO2PR, geophysical field data (seismics and electromagnetics) will be collected during a research cruise offshore Norway currently planned for 2024. The resolution and efficiency of associated inversion techniques will be made usable for large-volume (Gt) reservoirs and complemented with new AI methods to identify signals suitable for monitoring.

Oman’s listwaenite formed when carbonate-rich fluids reacted with peridotite, reducing the atmosphere’s carbon. Listwaenite provides clues regarding natural global carbon flux and sequestration. Oman contains the world's largest exposure of oceanic lithosphere. Obduction of the peridotite-bearing Semail Ophiolite onto Arabia occurred during the Late Cretaceous. The ophiolite’s hot base exerted contact metamorphism onto tectonically underlying rocks (“metamorphic sole”). Post-obductional doming, extension and E/W-shortening overprinted the rocks. In the Fanja area, (par-)autochthonous platform rocks are in contact with allochthonous rocks, and numerous listwaenite bodies several kilometers long and tens of meters wide are exposed. Mapping of the Fanja area at the scale of 1:10,000, determined the listwaenite’s tectogenesis. Two models exist. Listwaenite formed either during Late Cretaceous convergence and subduction or during shallow post-obductional extension. Mapping confirms: (i) Two listwaenite generations exist: an early gently dipping and a more common late steeply dipping generation. (ii) Listwaenite contacts of both generations with the ambient rocks are always a non-contractional fault. (iii) The listwaenite-metamorphic sole contact of the older listwaenite bodies is discordant and faulted. (iv) Both listwaenite generations are typically tabular, while the metamorphic sole may be intensely folded. (v) Drag folds and Riedel faults indicate extensional and/or WNW-striking sinistral shear of the late listwaenite. (vi) The late-generation bodies cut different sections of the allochthonous. (vii) At the Fanja Half-Graben, listwaenite is in extensional fault contact with post-obductional sediments (uppermost Cretaceous Al-Khod Fm.). No listwaenite clasts are found within this formation. Our observations demonstrate that all listwaenite bodies formed during extension.

Box modeling is a versatile tool to explore earth systems processes, ranging from transient changes in the marine carbonate system to the long-term evolution of biogeochemical cycles. The Earth Science Box Modeling Toolkit is a python based toolkit that allows for the rapid creation and deployment of box models. It abstracts typical modeling tasks, e.g., air-sea gas exchange, weathering, seafloor carbonate precipitation/dissolution, kinetic isotope fractionation, etc., to python classes. Class instances can then simply be combined to build a model. While there is no graphical interface, this approach significantly reduces coding complexity and model development time. Crucially, the model structure is independent of the numerical implementation. Instead the model is parsed to dynamically create the necessary equation systems that can be passed to ode solver libraries like ODEPACK. Separating model description from numerical implementation results in well-documented model code, and combines the computational efficiency of state-of-the-art numerical libraries with the ease of use of python. The efficiency of this process is demonstrated by a 12-box model with air-sea gas exchange, tracers for carbon isotopes, and water column carbonate chemistry that requires about 1 CPU second to calculate the model evolution over 30 million years.

Recently, interest in hydrogen as an emission free fuel has increased. So far, hydrogen is produced by steam methane reforming (SMR), water electrolysis or methane pyrolysis. These processes are energy consuming and SMR emits carbon dioxide. Naturally occurring hydrogen might represent an alternative to technologically produced hydrogen. It is therefore worthwhile to explore whether economically viable amounts of hydrogen are present in the earth.

Whereas a wealth of hydrogen on earth is considered to be trapped in the earth’s core and lower mantle and mostly inaccessible to humans, natural hydrogen also occurs in the crust and upper mantle where it is formed from biogenic and abiogenic sources. Important processes for the generation of natural hydrogen include: water-rock interactions involving ferrous iron, e.g. serpentinization, equilibrium reactions associated with volcanic activity and hydrothermal vents, water radiolysis, mechanochemical reactions in cataclastic rocks associated with fault zones and thermal decomposition of organic matter to form graphite at high temperatures in deep sedimentary basins or crystalline basement.

The presence of hydrogen-rich gas was documented at Mid-Ocean-Ridges, ophiolites, sedimentary basins, and Precambrian cratons. A multitude of studies on natural hydrogen exists, but the relationship between generation, fluid migration and potential occurrence of economic accumulations of natural hydrogen is still a matter of debate.

We present an overview of the current published knowledge on natural hydrogen showing selected study locations of previous works and the amount of naturally occurring hydrogen inferred at each site. The methods used to estimate the amount of occurring hydrogen are reviewed.

Hydrogen, converted from renewable energy sources, provides a feasible road map to balance the daily up to seasonally fluctuation between renewable energy supply and consumer demand. Underground hydrogen storage (UHS) in porous formations is promising since depleted hydrocarbon reservoirs and aquifers are widespread worldwide, and have a large capacity to meet the G-TWh storage demand. However, unlike underground natural gas (mainly methane) storage, hydrogen is highly susceptible to microbial metabolisms, which can consume and convert hydrogen into other molecules such as methane through methanogenesis. This poses a risk of hydrogen loss and contamination. Another concept is geo-bio-methanation directly in the subsurface, enabling stable long-term storage. Both concepts require a thorough understanding of microbial activities within porous rocks. The key questions, including, 1) does microbial growth reduce reservoir performance? 2) is there any effect of minerals and pore microstructures on microbial activities? 3) how do static and flow conditions affect microbe distribution? need to be better elucidated. To tackle these questions, we develop an unconventional real-rock micromodel configured with a thin rock layer in a transparent microfluidic chip. This innovative setup allows us to visualise microbial growth in rocks under a fluorescence microscope. By employing real-rock micromodels, we can overcome limitations related to mineral homogeneity and artificial pore structures. Consequently, this workflow and platform may hence offer new possibilities for studying microbial metabolism in geo-materials and the potential interactions.

Geological hydrogen storage in saline aquifers is necessary due to their large capacities, enabling long-term and short-term storage and providing a secure and cost-effective option for integrating hydrogen into the energy system. Currently, there are no operational saline aquifer storages for hydrogen in Germany. However, there is an urgent need for investigating the desired capacity and performance of hydrogen underground storage facilities in deep saline aquifers as one of the most promising geological environments.

In this study, the sedimentary Stuttgart formation at the Ketzin site in Brandenburg, Germany, is assessed for geological hydrogen storage using an open-source reservoir simulator. The site has already been used for town gas and natural gas as well as for pilot CO₂ storage in the past decades. The experience from these storage operations can be transferred to a potential hydrogen storage system.

The goal of the investigation is to evaluate the influence of geological parameters of the heterogeneous formation such as porosity, permeability, salinity, and capillary pressure on flow rates, quantities as well as on the recovery rate. The range of each parameter agrees with the measured uncertainty of petrophysical data. The results of the pre-feasibility study are then considered in the context of the regional hydrogen economy.

Overall, this multidisciplinary approach combines numerical simulations, geological parameters, and regional economic considerations. Future studies will focus on optimizing the operational parameter to minimize well-head pressure difference between charge and discharge cycles, to maximize production rates, and to achieve net-zero cumulative injection of hydrogen over time.

Despite the high salinity, biological processes could be used in salt caverns for methanation if suitable conditions are created. With suitable backfill materials, growth areas for the formation of biofilms could be created and the availability of sulfate could be reduced. These backfill materials can also be used in the course of cavern containment to reduce convergence.

Large scale experiments enable the simulation of cavern filling with suitable porous materials and the testing of growth material to promote biofilm formation. The aim is to develop an underground methanation reactor that also minimizes the convergence of the cavern. Therefore, it has to be tested if methanogenic archaea can survive under the given conditions.

We use an autoclave system with a volume of ca. 35 liters. Pressures of up to 100 bar and temperatures of up to 100 °C are possible. The autoclave consists of two chambers and a 2.5 m long casing in between. For safety reasons, the gas will contain 95 % N2, 4 % H2 and 1 % CO2. The bottom of the autoclave will be filled with brine and salt. As filling materials, expanded clay and construction waste are foreseen.

The European Marine Observation and Data Network (EMODnet) is a long-term marine data initiative funded by the European Maritime, Fisheries and Aquaculture Fund (EMFAF) and supported by the EU’s integrated maritime policy. The EMODnet Geology team released in 2023 a series of pan-European products related to marine themes including Seafloor geology, geological events, submerged landscapes, and Marine Minerals. Data products are available through the integrated EMODnet Central Portal: https://emodnet.ec.europa.eu/en. Collated marine mineral types and energy resources are: aggregates; hydrocarbons; gas hydrates; sapropel, marine placers; phosphorites; evaporites; polymetallic sulphides; polymetallic nodules; cobalt-rich ferromanganese crust; metal-rich sediments; rock, pegmatite and vein hosted mineralisation. The marine minerals theme is also connected to the five-year EU Coordination and Support Action, GSEU, (EuroGeoSurveys) that will deliver a plan for a sustainable Geological Service for Europe to be implemented beyond the 2027 project end, including assessing Europe’s offshore CRM resources improving the knowledge of underexplored areas and their mineral resources harmonizing datasets and cartographic products with a focus on European strategic and CRM for power generation and energy storage. With Earth’s population growth, efforts to meet our needs for resources with indigenous supplies continue. Many minerals and critical raw materials form important components in low-carbon and resource-efficient technologies such as electric car batteries, wind turbines and solar panels. Information on the types of minerals has relevance to engineering disciplines including extractive industries, beach nourishment and reclamation projects, and more general in Marine Spatial Planning. Environmental and marine EU policies are benefiting from the project’s outcomes.

Polymetallic nodules (including ferromanganese) are one the major metal-bearing sources, those admitted as strategic and critical raw materials (CRMs) by the European Commission. Their widespread on seas’ and oceans’ bottoms entail interests in economic use of them.

Ferromanganese (Fe-Mn) nodules occur on the seabedof most areas of the Baltic Sea. Those from the Polish Exclusive Economic Zone (PEEZ) are ones of least explored elements of the marine environment. Since 2020 there have been 3 research cruises on the area of the PEEZ - on 3 selected areas, 25 km2 each (near Baltic Beta oil rig, Slupsk Furrow and Gdansk’s Basin). Almost 100 sediment samples from the seabed were collected by Van Veen sampler and box-corer. So far, more than 2000 samples of nodules have been described and analyzed.

The main assumptions of the project are to determine:

• mineralogical and chemical compositions, genesis, age;

• geochemical variability of Fe-Mn nodules and their relation to bottom sediments and the morphology of the bottom surface;

• directions for depositional potential based on chemical composition for averaged samples of the areas in the PEEZ.

The chemical investigation (by using of ICP-MS) performed on the new nodule samples from the Słupsk Furrow and the edge of the Gotland Basin showed the average REE content at the level of 164.33 ppm (from 118.40 ppm to 202.74 ppm). There is a visible small positive Li anomaly (from 60.40 ppm to 444.60 ppm).

Further research investigations may redound more data in the context of economic potential.

As part of project D-AERO Finsterwalde, the “Bundesanstalt für Geowissenschaften und Rohstoffe” (BGR) carried out an airborne geophysical study in a former opencast lignite mining area in summer 2021. The area (260 km², 1742 line-km) surveyed using BGR’s helicopter-borne geophysical system (electromagnetics (EM), magnetics and radiometrics) is located about 60 km southwest of the city of Cottbus. The project was conducted in cooperation with “Lausitzer und Mitteldeutsche Bergbau-Verwaltungsgesellschaft” (LMBV) and in consultation with “Landesamt für Bergbau, Geologie und Rohstoffe Brandenburg“ (LBGR). The results (Siemon et al., 2022) include a comparison of the resistivity models derived from EM data with a geological database provided by LMBV and corroborates the validity of the resistivity models.

We present here the first results of “FINA”, a new project by BGR´s „Forschungs- und Entwicklungszentrum Bergbaufolgen” (FEZB) that, among several other goals, aims to make use of the collected helicopter-borne EM information to complement the previous analysis. Using machine-learning algorithms, the EM models are analyzed searching for patterns previously not seen. An in-depth analysis is performed based on geological and geophysical databases, now complemented with geophysical logs and further geological borehole information provided by LBGR. These results will be used in the near future to refine a new 3D geological model of Lusatia currently in development, in order to obtain a better understanding of the water distribution and flow patterns in that region.

The hydrology and hydrogeology of the German Lusatian mining district has strongly been impacted by open pit lignite mining. During active mining, mines are dewatered to lower the groundwater tables below the coal-bearing layers (up to 100 m below the surface). Following the phase-out of current mining activities, groundwater levels will rise and groundwater will reconnect with surface water. The groundwater-surface water interactions strongly influence flow patterns and dynamics as well as hydrochemistry and water quality, and are still largely unknown.

It is therefore planned to systematically select up to five representative post-mining lakes to conduct detailed measurement of climatological parameters and stable isotopes (deuterium, oxygen-18, and sulphur-34). The overall goal of this work (IsoGon project) is the characterization of surface water-groundwater interactions and the quantification of evaporation losses from the post-mining lakes in Lusatia. In this contribution, we summarize our planned project activities, state of the project, current understanding of the subject and our objectives of further planned work.

The EU Water Framework Directive (WFD) demands a good ecological status or ecological potential for natural and artificial lakes larger than 50 ha until 2027. More than 100 artificial mining lakes originate from lignite mining activities in Germany. The specific chemistry of mining lakes with their high phosphorus retention capacity is a chance for the development of clear lakes that are poor in nutrients. For neutral mining lakes, the existing typology for natural lakes which is based on the biological quality elements was adapted. For acidic lakes, the phytoplankton assessment was modified by including the diversity of the phytoplankton. In total, 36 of the largest existing mining lakes in Germany were assessed and description of the limnological lake characteristics were elaborated. Some of the relevant lakes could not be sampled because they are still in filling process and under surveillance of the mining authorities or safety demands for sampling are not given. So far, 53 % of lakes considered in this study reach the good or better ecological potential. Three lakes fail this state because environmental quality standards for river basin-specific chemical pollutants are not complied. Only one lake shows too high trophic conditions. The currently applied assessment tools especially those for macrophytes and microphytobenthos do not meet the requirements for the specific ecological situation in acidic mining lakes. Therefore, these results can only be regarded as an intermediate status of assessment for mining lakes. A revision of the assessment process of macrophytes and microphytobenthos in acidic lakes is recommended.

Laminated sediments of lake Stadtsee, located next to the city Bad Waldsee, provide a unique archive of socio-economic and environmental history since Medieval times. In this study we explored the composition patterns of PAHs and DMP together with the sedimentary charcoal influx records as indicators of variations in natural and anthropogenic fire activity from 1200-1800.

Charcoal particles and organic pollutants are emitted from incomplete combustion in the surrounding area as well as in the city and thus deposited in sediments. Pyrogenic Polycyclic aromatic hydrocarbons (PAHs) can be linked to vegetation types, householdburnings or pre-industrial production. In particular, the co-occurrence of charcoal and PAHs including dimethyl-phenanthrene (DMP) isomers can be used as a proxy to distinguish natural- and human-related historical fire activity. However, this proxy has rarely been applied for the time period before 1800.

Macro charcoal results show 15 screened charcoal peaks, which group into two phases of biomass burning. The first phase in the late Medieval period show high proportions of burned grass and monocot leaves, whereas in the second phase in the early Modern Times wood was the main fire fuel. The obtained PAH patterns, in particular the DMP isomers ratio (1.7-DMP/1.2-DMP), support the change in fuel source. High perylene values in late Medieval time indicate biogenic processes under anoxic conditions and suggests delivery of terrestrial organic material by water.

The Cenozoic cooling that occurred over the past 50 Ma is accompanied by an increase of Mg/Ca ratio in seawater. How this change in seawater chemistry is linked to climate change is still disputed. Mg isotope ratios of seawater could distinguish several possible causes including dolomitization, authigenic clay formation and changes in rates of silicate- and carbonate weathering. Former reconstructions of Mg isotope ratios of paleo-seawater are based on foraminifera, corals or carbonate muds, which however yield conflicting results. Here we assess the suitability of the bivalve Glycymeris as an archive for paleo-seawater δ²⁶Mg (the standardized ²⁶Mg/²⁴Mg ratio). Their potential as geochemical archive advantage arises from their strong evolutionary conservatism, thick shells and a fossil record dating back to the Early Cretaceous. We report Mg isotope signatures of shells of three recent Glycymeris species from the Adriatic Sea that show an increasing fractionation with increasing ontogenetic age, a property that we use to determine δ²⁶Mg of paleo-seawater from fossil Glycymeris specimens.

The aim of our study was to investigate the driving factors for shell growth in G. glycymeris bivalves by analysing the growth patterns and stable oxygen and carbon isotope compositions of shells collected from the Atlantic coast of the Iberian Peninsula.

An increment chronology, covering the 1985-2001 period, was established from the shells and was used to explore longevity and growth responses to environmental parameters. The inter-annual fluctuation of increment widths displayed a positive correlation (r=0.49, p < 0.05) with the regional March sea surface temperature (SST), suggesting that at this collection site, late winter SST is limiting the growth of the studied bivalve species. Significant negative correlations were observed with precipitation (r=-0.69 p<0.05) and also with sea surface salinity (r=-0.59 p<0.05) in February associated with complex hydrological processes of the Iberian Shelf. Intensive regional precipitation in June seems to have a positive effect on shell growth.

Comparing sub-annually resolved oxygen isotope ratios from three specimens with overlapping lifespans (1984-1993) to satellite-derived temperature data proved that summer SST maxima were recorded within the shell carbonate, whereas annual minima are not reflected.

Our results imply that annual growth rates of G. glycymeris shells collected near Aveiro are affected by summer runoff events and late winter SSTs. The latter connection is more difficult to explain as Glycymeris shell growth usually slows down or ceases during this period. Late winter stages of Glycymeris reproduction may affect their sensitivity to late winter SSTs and may have possible consequences for the overall annual shell growth.

During the Early Holocene Humid Period (EHHP), a perennial lake was located in the endorheic depression north of the modern settlement of Tayma in Saudi Arabia. While the climate in this area is arid to hyperarid today, it was arid to semiarid during the EHHP. A deep lake phase occurred around the 8.2 ka BP climate deterioration that led to general cooling and drying on the Arabian Peninsula. Foraminifers and ostracods in the sediments of the sabkha basin represent a brackish to hypersaline inland water fauna, which provides valuable information on the past precipitation/evaporation balance. In the lower part of an analysed core section from the deepest part of the basin, they reflect the beginning of the EHHP with a transition to a more humid phase and the development from slightly saline wetlands to a shallow brackish lake, shown by increasing microfossil abundances, a decreasing adult/juvenile-ratio in ostracods, and an increase of δ¹³C. This culminated in a deep lake phase at ca. 8.3 cal. BP. Varved sediments from two sections contain ostracods and foraminifers which are more abundant in the dark layers, indicating more favorable living conditions during deposition of these layers. This is also indicated by higher frequencies of juvenile carapaces in the light layers, suggesting possibly higher juvenile mortality rates. A sieve pore analysis in ostracods valves proposes distinctly higher salinities during deposition of the light layers. The seasonal variances in the microfossil assemblages may reflect generally dry summers and more humid winters.

Shell carbonates of marine molluscs are a widely used archive for paleo-environmental reconstructions. However, their use for temperature reconstructions may be impeded by species-specific vital effects and/or a lack of knowledge of the chemical and isotopic composition of paleo-seawater. Clumped isotope (∆₄₇) thermometry of marine carbonates enables temperature reconstructions independent of seawater composition provided the carbonate formed in thermodynamic equilibrium. Dual clumped isotope thermometry, i.e. simultaneous analysis of ∆₄₈ alongside ∆₄₇, offers the opportunity to determine if a carbonate formed in isotopic equilibrium and to account for kinetic effects taking place prior to and/or during precipitation. Here, we present dual clumped isotope data for several modern mollusc specimens (including bivalves and gastropods) with average growth temperatures ranging from 5-27°C. We find that most specimens analysed in this study exhibit dual clumped isotope compositions which are indistinguishable from equilibrium. Moreover, their ∆₄₇-derived temperatures agree within errors with their growth temperatures. We interpret the apparent equilibrium calcification of mollusc shell carbonates to be a possible consequence of a relatively low pH at the site of calcification. The absence of any resolvable kinetic isotope effects makes molluscs a reliable archive for highly precise (95CI of <2.2°C) temperature reconstructions via ∆₄₇-analysis. Based on previous ∆₄₇ investigations of molluscs grown at known seawater oxygen isotope compositions (δ¹⁸O_SW), we also determine the temperature dependencies of the oxygen isotope fractionation between seawater and molluscan aragonite/calcite.

∆₄₇ and δ¹⁸O values of fossil molluscs may be used in conjunction with these calibrations to reconstruct both - seawater-δ¹⁸O and temperature.

Tropical cyclones (TCs) such as hurricanes are amongst the most devastating natural disasters of the modern world causing massive humanitarian, ecological, and economic damage every year. A better understanding of timing and frequency of TCs must, therefore, be a key priority for building resilience of affected countries. Within this project, we investigate a stable isotope-based approach for the reconstruction of paleo-TCs through the integration of ecological and morphological data with isotope geochemical signatures of modern ostracodes in relation to the hydrochemistry from a tropical lake located within the Main Development Region of TCs (Lago Enriquillo, Dominican Republic). Water samples were taken during two seasons in 2022 on different vertical profiles through the lake, associated tributaries and closed-by water bodies. Besides in-situ characterization, samples were taken for major, minor, and trace elements using different analytical approaches, and the stable isotope signatures of water (²H, ¹⁸O; CRDS spectroscopy), dissolved inorganic carbon (¹³C; gas mass spectrometry), and sulfate (³⁴S, ¹⁸O; gas mass spectrometry). Hydrochemical data were further evaluated using the speciation model PHREEQC.

Substantial changes in the lake composition were observed between the two campaigns. Together with an evaluation of element stoichiometries, the water isotopes allow for an evaluation of sources and evapotranspiration. Carbon and sulfur isotopes allow to deduce the role of microbial activity and solution-atmosphere exchange on the modulation of the dissolved carbon system, in contact with solid phase carbonates, like ostracod shells

Outcrop and sub-crop evidence from the Lower Triassic Sherwood Sandstone Group (SSG) suggests a northerly flowing braided river deposited pebble-rich red sandstones through several UK basins. Previous workers assume the sole source of this ‘Budleigh Salterton River System’ to be the Armorican Massif, based on dominantly metaquartzite pebble composition, paleoflow orientations and lithostratigraphy trend. However, a proximal to distal facies trend northwards from an Armorican Massif source should mean pebble-sized clasts decrease in abundance northwards, yet pebble-rich sandstones and conglomerates are seen through several basins with slight variations in composition, perhaps indicating that other topographic high areas adjacent to the river system also provide a source for the pebble clasts via tributary drainage systems. This study conducted fieldwork to collect data specifically surrounding clast inclusions pebble clasts, including clast size, abundance, and orientation, to determine if/where possible tributaries occur. Pebble abundance was plotted against distance using Matlab software, with a simple model inversion used to assess the distance from the source. Our results indicate a three source-model is most likely, suggesting local sources are present and significant contributors to the overall sediment budget. Using spatial distributions of pebble abundance, one tributary was likely located from the Welsh Massif and a second from a potential basin margin fault. These results contrast previous models, which suggest the majority of sediment was sourced from the Armorican Massif, and raise several questions about the distribution of Triassic sediment fairways across the UK.

The Adula nappe in the Swiss-Italian Central Alps is a continental basement nappe from the former European margin that was subducted to depths indicating (ultra)-high-pressure conditions. Many studies were performed to understand the pressure-temperature-time evolution of the Adula nappe. The Adula nappe underwent eclogite-facies metamorphism during the Variscan and Alpine orogenic cycles but the Variscan and Alpine parageneses are hard to distinguish.

For this study, around fifty samples were collected from different lithologies on a N-S transect through the Adula nappe parallel to the direction of subduction. Raman spectroscopy on quartz inclusions in garnet was used as a geobarometer to measure minimum peak pressures. This method is independent of chemical equilibria and yields reliable pressure constraints even if the high-pressure mineral assemblage has been retrogressed. Variscan and Alpine garnet domains were identified using the Electron Microprobe and Scanning Electron Microscopy.

The Variscan peak pressure was at least 2.3 GPa. For the Alpine metamorphism, the Zr-in-rutile temperatures exhibit a gradient increasing from ca. 500-550 ^oC in the north to around 700 ^oC in the south. The minimum peak pressures in the northern and central Adula nappe are 2.1-2.2 GPa for metasediments, 1.4-2.0 GPa for metabasites, and 1.5 GPa for an orthogneiss. Lower pressures of 1.1-1.3 GPa in the southern Adula nappe were potentially caused by viscous relaxation of the quartz inclusions during the high-temperature Lepontine metamorphism.

The Saualpe-Koralpe high pressure (HP) complex as well as the HP units of the Pohorje mountains formed during the Cretaceous orogenic cycle in the Eastern Alps. Within these units eclogite bodies can be found, which were probably emplaced along the rift zone that led to the opening of the Meliata ocean. After closure of the ocean ongoing convergence led to underplating within the lower plate, which led to the formation of the Austroalpine nappe stack. During subduction, the Saualpe, Koralpe and Pohorje units reached peak pressure conditions of 2.2-2.4 GPa/630-690°C, 1.8-1.9 GPa/670°C and 3.0–3.7 GPa/710–940 °C, respectively. PT-analyses, microstructural investigations and dating predict different contrasting models for the subsequent exhumation of these units.

Here, we investigate the deformational history of these units during their exhumation. We sampled sets of pristine eclogites, retrograde amphibolite facies shear zones as well as neighboring gneisses surrounding the eclogite lenses. The samples were analyzed by electron backscatter diffraction (EBSD) to determine their crystallographic preferred orientation (CPO) and deformation mechanisms. Both omphacite in pristine eclogites and hornblende in the amphibolite facies shear zones show a pronounced CPO. Hornblende yields distinct signs of dynamic recrystallization by subgrain rotation within the shear zones. Quartz CPO was analyzed in both the eclogites and the surrounding gneiss matrix. Results indicate a shear sense reversal during the exhumation of the Pohorje eclogites.

In this study we show CPO data that recorded the deformational path of these rocks from eclogite facies conditions up to the exhumation to crustal levels.

Understanding collision zones and their geodynamic processes is crucial for comprehending plate tectonics, mountain building, and seismic activities. This study employs the software MDOODZ for numerical thermo-mechanical modelling, specifically designed to simulate the mechanical behaviour and thermal evolution of rocks in 2D complex geological settings.

Focusing on a collision zone, we investigate the influence of anisotropy on geodynamic processes. Anisotropy, resulting from preferred orientations of minerals or rock structures, plays a significant role in the deformation behaviour and mechanical response of stressed rocks. By incorporating anisotropy effects using the director vector and transformation matrix approaches proposed by Mühlhaus (2002) and Fletcher (2005), respectively, we explore its impact on the overall geodynamic evolution of the collision zone.

Our 2D thermo-mechanical numerical model captures the essential dynamics of the collision zone, considering the coupling of mechanical and thermal processes, including rock rheology, heat transfer, and their interactions. Accounting for anisotropic properties enables us to investigate the implications of various orientations and strengths of anisotropy on geodynamic processes within the collision zone.

Our findings contribute to understanding collision zone dynamics, highlighting the significance of anisotropy effects in shaping geological processes. The utilisation of MDOODZ, in conjunction with anisotropy incorporation, facilitates exploring the intricate interplay between anisotropy and thermo-mechanical interactions in collision zones.

Slab detachment is a process that has been invoked to explain rapid uplift, deep seismicity, and magmatic activity in several active orogens (e.g., Alps, Himalaya). However, it is not yet clear to which extent slab detachment is the primary cause of these phenomena. Thus, deciphering the physical processes controlling the slab break-off is important to understand its impact on the post-collisional evolution of orogens.

Here, we employ numerical models to investigate the nonlinear coupling between mantle flow and slab detachment. Due to the three-dimensional nature of slab detachment and the variety of involved processes, it is daunting to pinpoint the first order controls on the time scale of this process. We, therefore, started to investigate this issue by developing a 0D necking model that describes the temporal evolution of the thickness of a detaching slab. We accounted for the effects of the nonlinear coupling between upper mantle and detaching slab and derived a set of nondimensional numbers that control the slab detachment process.

Based on these findings, we, then, used 2D and 3D numerical models to further determine higher dimensional geometrical effects on slab detachment. Results show that the predictions from the 0D experiments predict simple 2D and 3D experiments sufficiently well. For more complex slab geometries, higher dimensional results deviate from the 0D predictions. Nevertheless, the combination of 0D and 2D/3D numerical models allows to determine first order controls on slab detachment and thus also on specific geological observations such as seismicity and surface response.

The KSP Complex in the Eastern Alps is a lithologically heterogenous (U)HP nappe with eclogite lenses embedded in gneisses and metasediments. The formation history of the KSP Complex is still debated. Here, we investigate in detail the pressure and temperature conditions during the formation of the complex along a NW-SE transect following the direction of subduction. This is the first study where quartz inclusions in garnet elastic barometry was conducted to determine the entrapment pressures, which correspond to the minimum pressure conditions present during the entrapment of quartz inside garnet. The eclogites yield pressures of max. 1.9 GPa across the KSP complex, indicating no pressure increase from the NW to SE. The metasediments and gneisses show overall lower pressures with ca. 1.4 GPa. Temperatures based on Zr-in-rutile thermometry do not indicate a temperature increase from NW to SE, with ca. 640 (±30)°C across the whole KSP Complex, based on very similar Zr content of ca. 270 ppm. U/Pb dating on garnets in metasediments provide the following ages for the Koralpe 101.3 ± 6.6 Ma (throughout garnet); Saualpe 224.6 ± 31 Ma (core) and 95.43 ± 5.6 Ma (rim); Pohorje 99.83 ± 5.85 to 104.2 ± 7.1 Ma (throughout garnet). Garnet in eclogite from Koralpe is 112.8 ± 9.9 Ma. Combined with results of previous studies of eclogite ages, we suggest, that the eclogites are former (probably Permian) gabbro intrusions that experienced HP conditions during the Eo-Alpine orogeny. Whereas garnet ages of metasediments from Saualpe provide evidence for a polymetamorphic history.

The elastic interaction between an inclusion and its host is often employed to study the entrapment conditions during metamorphism on the assumption that the host is not affected by creep. However, it is not well understood how fast creep-induced relaxation may occur and under what conditions the elastic regime holds for each crystalline inclusion-host system. In this study, we performed heating experiments on eclogite and spessartine garnets under 1) graphite, 2) N₂+H₂ and 3) H₂O+Ar fluxed conditions at different temperatures. Raman spectroscopy is used to measure the same quartz and zircon inclusions after different heating times. The Raman-band wavenumber undergoes a time-dependent decrease in quartz inclusions and increase in zircon inclusions under H₂O+Ar and H₂+N₂ conditions, but stabilises after the first heating step under graphite-buffered conditions. EBSD results reveal greater misorientation around the heated inclusions compared to unheated inclusions. Raman mapping reveals that stress heterogeneity in the garnet host develops first and fades away afterward, indicating dispersal of dislocations into the host. A visco-elastic model fit to the measured Raman data provides estimates of flow-law parameters for garnet. These results demonstrate the efficiency of H migration and its weakening effect on garnet. The data also indicate that the garnet can be stronger than previously thought under a dry and reduced environment, which is consistent with the high activation energy of Si diffusion in dry garnet. This study provides a critical temperature and water limit for elastic thermobarometry and criteria of determining whether an inclusion has been reset or not.

As part of the retrieval planning of radioactive waste from the ASSE II salt mine, located in the western part of the Asse-Heesberg salt structure south-east of the city of Braunschweig in northern Germany, a detailed and consistent 3D geological model of the internal structure is required. It’s used as a planning tool for the construction of a recovery mine and includes the Zechstein units from the Staßfurt to the Aller-formations (z2-z4). The data basis consists of a multitude of prospecting data such as drill cores, georadar reflectors, 3D seismic and dip values, for instance.

3D geological modelling of salt rock which has been highly deformed by salt migration and tectonical stress as well, faces some challenges. The various layers within the salt rock are strongly folded and overturned in parts. Lithologically different salt bodies often intertwine. The visualization of such complex structures often cannot be realized using conventional 3D modelling software that bases on fixed mathematical algorithms. Thus, details of the internal structure remain disregarded in many cases. Salt model surfaces can be shaped more precisely considering not only the input data, but also the geologic evolution of the salt structure. Therefore, in this project, we use a software (OpenGeo7) that requests complete manual drawing of the isobaths of the model surfaces. In the present study, we present some challenges and results of this type of 3D geological modelling.

The U.S. Geological Survey (USGS) has recently published a guideline for processing coastal imagery acquired by unmanned aerial vehicles (UAVs) based on the widely used Agisoft Metashape Professional software (USGS Open-File Report 2021-1039; Over et al. 2021). The guideline aims to improve the quality of photogrammetric reconstructions by iteratively removing low-quality tie points based on different cleaning parameters. However, the improvement procedure is iteratively performed and requires permanent attendance of the operator. Furthermore, the different cleaning steps are executed on a trial-and-error basis, adding up to the overall attentiveness required.

To minimise the time expenditure necessary for conducting the cleaning procedure and to provide a frame for the reproducibility of photogrammetric product derivations, we have compiled a python script to automate the tie point cloud optimisation as detailed in the USGS report. The graphical user interface of the script allows non-expert users to adjust important cleaning parameters, such as maximum reconstruction uncertainty, minimum projection accuracy and/or maximum reprojection error thresholds, and number of iterations to be performed. Furthermore, main tie point cloud quality measures can be directly assessed. We will demonstrate that the time required to clean tie point clouds (using a computer equipped with a 3.60 GHz processor, 64 GB Ram, and NVIDIA Quadro M4000) can be significantly reduced, such that cleaning of a (unprocessed) ~8 million tie point cloud is achieved unattended in about 30 minutes (default cleaning threshold values used), with ~7 million tie points being automatically removed while significantly increasing point cloud quality measures.

The Halle Fault in central Germany is a major tectonic fault that separates the lower permian rocks (Rotliegend) in the north from triassic rocks in the south. While geological modeling of the Cenozoic and Mesozoic rocks on both sides of the fault has been carried out frequently in the last two decades, the Paleozoic volcanics and sediments of the Permo-Carboniferous rocks in the Halle-Wittenberg-Scholle that outcrop in the urban area have not been modeled in 3D. This study aims to fill this gap by proposing a 3D GIS-based modeling approach to model the geometric and stratigraphic relationship of the volcanic rocks and host-sediments of the Halle-Wittenberg-Scholle.

The approach relies on standard geological data, such as geological maps, boreholes, and digital terrain models, from which geological cross sections are generated and used for further modeling. Existing profiles and seismic data are desired and can bring advantages in the modeling process. While attempts to develop an open-source modeling tool have already been made, they require programming skills, making this GIS-based approach more accessible to a wider audience.

For this purpose this research aims to make the proposed method publicly available, enabling anyone to create a 3D geological model without the need for specialized and costly modeling programs. This approach facilitates an ideal exchange between students and scientists, promoting further understanding and exploration of the possibilities of geological 3D modeling, and also advancing the understanding of the geological features of the Halle Fault.

Ökosystem- und Klimaänderungen sind äußerst aktuelle und brisante Themen, die bei einem großen Teil der Bevölkerung auf breites Interesse stoßen. Bei der Unterscheidung zwischen anthropogen beeinflussten und rein natürlichen Änderungen spielen paläoklimatologische Untersuchungen eine wichtige Rolle. Die Ergebnisse solcher Untersuchungen geben populäre Medien jedoch zum Teil missverständlich oder gar verfälscht wieder. Oft veröffentlichen Medien Ökosystem- und Klimadaten und diskutieren diese, doch die Ansätze zur Ermittlung der präsentierten Daten, ihre Verlässlichkeit sowie ihre Anwendbarkeit bleiben NichtwissenschaftlerInnen oft verschlossen.

Ein guter Weg, interessierten Laien natürliche Klimaänderungen zu erläutern und generell das Verständnis für wissenschaftliche Forschung zu stärken, sind vereinfachte Fallstudien z. B. anhand von synthetischen Pollenpräparaten. Wir stellen solche Studien vor und diskutieren ihre Umsetzbarkeit in Museen, Schulen und der universitären Lehre anhand des Beispiels eines Kurses zur Pollen-basierten Paläoklimaanalyse mit Grundschulkindern, bei dem theoretische Fragen mit Analysen und haptischen Arbeiten verknüpft wurden. Wir legen weiterhin dar, wie solche Kurse in verkleinertem Umfang auch bei öffentlichen Veranstaltungen umgesetzt werden können.

Geoparks serve as an important link between science and the public. Through the lens of geotourism, they not only strengthen regional development and sustainable economics but also offer an interesting encounter with geology and the profound story of our planet’s past. Geoparks provide universal access to the habitat Earth and thereby enhance the respect for nature within society. Since last year the Geopark Ries has been labeled UNESCO Global Geopark, highlighting its remarkable geological heritage on the global stage. The concept of the Geopark Ries is designed to captivate, interest and educate individuals from diverse backgrounds. Even from a very young age, visitors are able to dive into Earth’s history via child-firendly educational programs. Numerous geosites, expert-led tours and thematic hiking trails not only deepen the understanding for the environment and geology of interested locals and tourists but also grant researches and students access to the type locality of Suevite and Riesite.

Therefore, Geoparks play a significant role in raising public awareness regarding the relationship between geology, nature and humanity, thus laying a solid foundation for a sustainable future.

Neben geologischen besitzen Gesteinsgrenzen auch die mathematische Eigenschaft der Gleichheit oder der Kongruenz. Im Einheitskubus des NGS können durch die Mittelsenkrechte vier kongruente Dreiecke in der lotrechten Ebene und vier kongruente Prismen dargestellt werden. Der geometrische Zusammenhang ist begründet durch das mathematische Axiom der Kongruenz. Die Kongruenz der Gesteinsschichtung ist ein rein geologisch begründetes Faktum der Geologie, die Erklärung desselben Bedarfs keiner weiteren Entität.

Der Einheitskubus des NGS erklärt die Verknüpfung des Kongruenzaxioms mit dem Parallelenaxiom in der Geologie. Das Parallelenaxiom ermöglicht den Ansatz der Messtechnik im geologischen Bau, die Einbeziehung des Zahlensystems und somit die axiomatisch begründete Komplexität in der Geologie. Die Veränderung der räumlichen Lage von Gesteinen aus einer ursprünglich horizontalen Lagerung in alle möglichen Schrägstellungen desselben verursachen Schnitte von unterschiedlichsten Flächen und Ebenen im geologischen Bau. In diesen Schnittlinien inzidieren unterschiedliche geologische Flächen und Ebenen miteinander. Die Spuren dieser Schnitte sind Linien der Inzidenz. Auswirkungen geologischer Schrägstellungen der Gesteine können durch das Axiom der Inzidenz erklärt werden.

Die Triade ist ein vollständiges, widerspruchsfreies und kategorisches System von Axiomen.Das NGS, ein mathematisches Objekt der Geologie, erklärt die Zusammenhänge der axiomatischen Triade in der Geologie. I.S. des Mathematikers David Hilbert (1862 – 1943) wird die Geologie durch ein System miteinander verknüpfter Axiome erklärt, das aus den Axiomen der Kongruenz, der Parallelität und der Inzidenz besteht. Die axiomatische Triade ermöglicht die Entwicklung einer "Theoretischen Geologie".

Handheld and portable X-ray fluorescence (XRF) spectrometers have evolved in recent years from being primarily used as metal sorting tools in scrap yards to becoming instruments of high analytical performance. However, this trend has not been fully embraced by the academic and research community, and there are multiple reasons for this. In this presentation we will provide a comprehensive description of the capabilities of these devices, particularly in the context in geo-analysis and archeometric research. We will cover typical analytical performance indicators, including instrument stability, limits of detection, precision and accuracy, as well as reproducibility in quantification. Furthermore, we will discuss how the hardware concept of the instrument influences its performance, allowing for a better understanding of the instrument's capabilities and limitations.

As a practical example, we will focus on the analysis of archaeological ceramics using the TRACER 5g. Ceramic analysis is a common research field in archaeometry that presents additional complexities for accurate elemental characterization. For this application, we will discuss strategies for optimizing measurement time and analytical parameters, tuning existing calibrations for the samples, validating results for publication requirements, and address the challenges of non-invasive analysis of precious artifacts. Additionally, we will explore how the combination of sample characteristics, analytical questions, and XRF physics are directly connected in this context. The presentation will provide a realistic assessment of the analytical performance of portable XRF instruments by offering a robust analytical evaluation that dispels existing myths surrounding this technique.

Fine-grained marine sediments are the largest permanent carbon sink on our planet. We chose the Helgoland Mud Area (HMA) as it represents the most important depocenter of such sediments in the German Bight and hosts a variety of sedimentary habitats that differ in key depositional factors – including water depth, sedimentation rates, grain size and origin of organic matter (OM). The HMA serves as a natural model area to (1) identify the main depositional drivers controlling the burial of organic carbon and (2) assess the efficiency of different sedimentary habitats as natural long-term carbon sinks. During two expeditions with RV Heincke, we collected a total of 16 MUC-cores from different areas of the HMA. Pore-water and solid-phase sampling and analyses were performed - including ²¹⁰Pb_xs to assess sedimentation rates and bioturbation depths, grain-size distribution, TOC contents and pore-water concentrations and stable carbon isotopic composition of DIC to determine the origin of the degrading OM. Sedimentation rates for the past ~200 years range from <0.5 to 6 mm yr^-1 with highest rates in the southern and central part of the HMA. TOC contents typically vary from 1 to 2 wt% with highest values in areas of highest sedimentation rates. The source and reactivity of the degraded OM show large variations, ranging from marine origin in the NW to terrestrial sources in the S of the HMA. The obtained data set will be subject to statistical analysis to determine the key factors controlling the burial of organic carbon in fine-grained North Sea sediments.

Available research on glacial isostatic adjustment (GIA) in Antarctica is sparse, and there are few records of how the stress field is affected by it compared to Arctic and northern regions. Circum-Antarctic coastal and offshore tectonics reveal the presence of faults and rift systems, particularly in West Antarctica, the Weddell Sea, and Prydz Bay. These areas are characterized by a series of complex faults that displace upper sedimentary sequences to depths of 2.5 km. In this study, we investigate the potential for reactivation of glacially induced faults (GIFs) by altered lithospheric stress conditions during ice advances and retreats in past glacial periods. We compiled available information on the dip and strike directions of Antarctic rift systems from the literature and databases. Using finite element simulations that incorporate fault geometries, various rheological and current stress parameters in solid and ice sheet models, it is possible to analyse the probability of fault reactivation due to GIA for the last 200 ka. Because West Antarctica has been subject to greater changes in its ice sheet in recent recorded years compared to East Antarctica, identifying potential sources of GIFs could help us better understand how seismotectonics in Antarctica have been affected by past glacial phases and what the implications of current global climate trends might be.

The geology of the Weser river terraces to the south of Hamelin is characterized by Quaternary sediments, consisting of thin alluvium and several meters of sand and gravels, overlying the seismic bedrock. We investigated a study area along the left Weser bank south of the village of Kirchohsen using different ambient seismic vibration techniques. Borehole logs show that the thickness of the Quaternary sediments varies from around 15 m to 33.5 m.

The fundamental frequency at a measurement point can be determined with the H/V method, which is based on the ratio between the horizontal and vertical spectra of the ambient seismic vibration signals. In the study area, the resonance frequency varies from 2.6 to 6.3 Hz, where low frequencies coincide with thicker Quaternary sediments and higher frequencies with thinner sedimentary layers. Assuming a continuity of the geological units, we can directly link the H/V frequencies to the sedimentary thickness and map the transition zone between the boreholes by H/V measurements along several profiles and additional individual points. We complement these H/V measurements by a new passive seismic array measurement and the reanalysis of older measurements in order to retrieve the dispersion curves of Rayleigh and Love waves and invert them for the shear-wave velocity profile.

The combination of the different data provides a detailed overview of the lateral changes within the shallow underground structure of the sedimentary layers of the study site.

Within the framework of the project Neotectonics in the Northern Upper Rhine Graben (NeoNORG), we used a multi-method geophysical approach to obtain a detailed understanding of the fault structures within the sedimentary basin.

Using parts of a 3D seismic data set originally conducted by the petroleum industry we were able to obtain a detailed 3D structural model. It consists of two main faults originating from the basement at a depth of 2 km to about 350 m below the surface. To close the gap between the 3D Seismic data and the surface, we conducted 2D P-wave profiles with geophone spacings of 2.5 m. For the uppermost 200 m, an even higher resolved image of the subsurface was obtained using 2D S-wave seismics with geophone spacings of 1 m. Geoelectrics with varying electrode spacings and georadar using 200Mhz antennas were used to resolve the uppermost 50 m.

The combination of these different geophysical investigation methods allowed us to trace the fault zones within the sedimentary basin from the crystalline basement at a depth of 2 km into the quaternary strata, several meters below the earth's surface. We thereby reveal the (neo)-tectonic activity of the investigated area. Overall, the study provides valuable insights into the development of fault zones in the Northern Upper Rhine Graben and demonstrates the importance of using a multi-method geophysical approach to investigate the tectonic development. The obtained fault outcrop at the surface is concurrently used to investigate the relationship of radon in soil gas and fault zones.

The assessment of seismic hazard and potential earthquake secondary effects such as tsunamis in offshore environments requires, similar to onshore environments, a good knowledge of the subsurface shear-wave velocity (Vs) distribution with depth. Between 2018 and 2020, a seismological campaign with Ocean Bottom Seismometers (OBS) was performed on selected subaqueous slopes with unconsolidated sediment cover in Lake Lucerne (Switzerland) to measure ambient vibrations and to monitore earthquakes. OBS were deployed in the single station and array configurations. First, we use the single station ambient vibration data to estimate the microtremor horizontal-to-vertical (H/V) spectral ratio. Second, we follow a robust preprocessing workflow to extract the phase velocity dispersion curves (DC) from OBS ambient vibration array measurements. The estimated H/V spectral ratios and the DC are used as targets in an inversion process for the Vs profile determination. The microtremor H/V spectral ratio forward modelling routine uses a new model that is based on the seismic interferometry principles under the diffuse field assumption and considers the presence of the water layer.

Keywords: Microtremor H/V spectral ratios, Phase velocity dispersion curves, Ocean
Bottom Seismometer, Site effects, Shear-wave velocity

Reflection seismics is the most common geophysical method for obtaining structural images of the subsurface. It can image subsurface structures over large areas and depth ranges at high resolution. In order to make a reliable assessment of seismic imaging results, e.g. to quantify uncertainties, it is important to understand the concepts of seismic resolution. At brief, seismic resolution is the ability to distinguish between two seismic features from one another and resolve them separately.

Theoretical considerations to seismic resolution criteria and their implications for seismic imaging are discussed in many textbooks, but the practical use in interpretation is often difficult to achieve. This is, because the underlying parameters, e.g. the bandwidth and the velocity of the seismic signal, are not explicitly visible on the final stacked image, especially if the sections are depth converted.

However, the measure for vertical resolution is the dominant wavelength and the resolution criteria is expressed as a fraction of it, e.g. λ/4 criterion, whereas a measure of the lateral resolution is the Fresnel zone. Both of which can be computed by common functions that are available in most interpretation systems. As a result, seismic sections showing the spatial variability of both vertical and horizontal resolution are obtained that can be blended into the stacked seismic section. This gives a tool at hand – just like a seismic attribute – to estimate the limits of seismic resolution and access uncertainties in the final seismic image.

Neotectonic movements can cause severe hazards and are scientifically and socially relevant for seismic hazard assessment and utilisation of the subsurface. In northern Germany, a presumed aseismic region, little is known about these processes and the associated structures, despite proven neotectonic activity, because many faults are hidden beneath sediments. To improve the knowledge of neotectonic activity, investigations of recently-active fault zones, like the Osning Lineament (OL) in North Rhine-Westphalia, are required.

To better understand the neotectonic evolution of the OL, we used a combined approach using high-resolution 2D P- and SH-wave reflection seismics to investigate four different sites at the Bielefeld-Segment of the OL. Overall, we acquired three P-wave profiles with which we were able to image the underground down to 700 to 800m depth, and four SH-wave profiles that imaged the subsurface down to 100m depth.

The seismic profiles show good results with respect to mapping the fault inventory. In the Cretaceous, Triassic, and Quaternary several, previously unknown, northward-dipping thrust faults are evident, which have upthrusted the formations toward the south. The faults form fault splays that developed due to the propagation of the OL into the footwall. The slow shear-wave velocities, especially in the Quaternary, allow for very high-resolution imaging of the subsurface and the identified faults are evidence for neotectonic activity. More to the south, we also observed some southward-dipping normal faults, which are interpreted as basin faults of the Münsterland Basin dipping towards the basin center.

Within the feasibility study regarding the construction of the Einstein – Telescope (ET), at a depth of 200 – 350 m in the Meuse-Rhine Euroregio, various seismic methods are used for subsurface investigation and imaging. The study includes a 40 km long two-dimensional active seismic-reflection survey using vibroseis. The vibroseis data provide a medium-resolution overview of the subsurface architecture including continuous reflection intervals and major discontinuities. Parts of the vibroseis survey were re-investigated using an electric vibrator to evaluate the potential of this environmental friendly seismic source. Extracted refraction data allowed to calculate a velocity model for the shallow subsurface. Additionally, passive seismic data were collected prior and during times of active surveying in the wider study area; linear data was used to optimise the station spacing for the area set-up and for the acquisition of seismic data perpendicular to the active survey. “Passive” area data were used to gather 3D insights. Geological interpretation of the various seismic reflection and refraction data integrated with subsurface knowledge from boreholes documented a major impedance contrast in the shallow subsurface caused by a prominent unconformity between Palaeozoic basement rocks covered by soft, partly consolidated Upper Cretaceous sediments. The soft-sediment cover effectively dampens surface-induced sounds in the target depth. This hampers the quality of subsurface imaging but is considered as beneficial for the operation of the ET in the Palaeozoic basement. With the collected passive seismic data, the main directions of surface generated noise and its denudation with distance from the respective sources can be identified.

Technology critical elements (TCEs) are widely understudied in aquatic systems. Many unknowns particularly are linked to the mechanistic understanding of TCE transport mechanisms in contrasting river systems. In this work, we aim at characterizing the colloidal vs truly dissolved TCE concentrations in three contrasting rivers in Germany (Rhine, Neckar and Danube) by comparing two filtering meshes (0.45 vs 0.02 µm). The seasonal component of such transport is also investigated based on monthly collections of water samples in 2023. TCEs were analysed via external calibration at the ICP-MS (iCAP series, Thermo®). Results suggest that each river has a different load on TCE concentrations, of which the colloidal transport differs even within the Rare Earth Elements and Yttrium (REEY) list. The seasonal influence is compared to water discharges and temperature ranges. These results provide further understanding of the watershed dynamics and can help identifying relevant processes that determine the unknown aquatic transport and fate of TCEs. This information can be used for developing scenarios for potential risk assessment of anthropogenic discharges from both stable and/or radioactive origin in surface aquatic environments in Germany.

Acknowledgements:

This work was funded by the Federal Ministry of Education and Research (BMBF) and the Baden-Württemberg Ministry of Science as part of the Excellence Strategy of the German Federal and State Governments. The authors also acknowledge the extensive contribution of the Landesanstalt für Umwelt Baden-Württemberg (LUBW, Germany) and the Amt für Umwelt und Energie (AUE, Switzerland) for the collection of water samples.

Iron oxide and hydroxide minerals are widespread in many aquatic environments and as such, can determine the fate of several metals of concern. Their role on metal mobility is generally studied under controlled conditions using synthetized materials. However, natural systems are complex and present a wide range of conditions, which may release metals differently to laboratory settings. In this study, we aim at understanding the mobility of geogenic, technology critical elements such as vanadium, nickel, cobalt, niobium, and tantalum from black sand sediments. These sediments from the OIB volcanic environment of the Canary Islands are the product of weathering and erosion of relatively geologically recent, ultramafic volcanic rocks composed of basanitic, phonolitic, nephelinitic and, locally, melilitic lavas and tuffs, sources of mafic heavy minerals deposited as a placer. The sediments were extracted through magnetic separation, characterized via XRD and SEM-EDS techniques, and further processed with a series of parallel selective extractions following widely applied protocols. Desorption kinetics during the extraction procedures were also investigated in order to understand the efficiency of the protocol for such sediments. Total element concentrations were quantified via XRF and LA-ICP-MS, whereas dissolved concentrations were determined via ICP-MS. Our results point towards contrasting selectivity during the extractions and different iron oxide mineral fractions in which these metals are bound. This information has a broad application for the potential environmental risk of metal mobility in aquatic systems.

Acknowledgements:

This work was funded as part of the Excellence Strategy of the German Federal and State Governments.

The GCI Rohrpassivsammler (tube-installed passive collector) is an innovative measuring device that uses the accumulation of water contaminants onto collector materials for integrative monitoring of varying concentrations, even for trace substances over long periods of time. The precise and adjustable flow and substance-specific calibration allow for a high level of sensitivity and quantitative evaluation of the collection results.

The patented measuring principle can be used with all water sources. The device has been successfully tested at production wells (installed in a bypass) and with treated wastewater, for the detection of explosives, industrial chemicals, and pharmaceuticals. Currently, applications for the detection of PFAS, Monochlorobenzene, and Lead are prepared.

In the latest design, concentrations are measured at short time intervals using substance-specific (bio)sensors, e.g. for Valsartan and Valsartanic Acid. A special design for installation in filter sections of groundwater monitoring wells is being developed which measures the concentration in-situ instead of pumping water to the surface. This design was successfully tested for detection of NSO Heterocycles. Future development is aimed at applications for surface water.

Quality and operation parameters are recorded digitally and wirelessly transmitted from the field for online access and visualisation.

Research and development are the Berliner Wasserbetriebe (BWB), the Fraunhofer Institute (IZI-BB), the Federal Institute for Materials Research and Testing (BAM), the Technical University of Applied Sciences Wildau (TH Wildau) and the Institute for Bioprocessing and Analytical Measurement Techniques (IBA). Development was funded by the German federal government (ZIM) and the state of Brandenburg (BIG ILB).

The role of clay colloids in facilitating or hampering the transport of cationic contaminants, such as heavy metal cations or radiogenic nuclides, in groundwater is well established. However, it is unclear whether this phenomenon occurs with positively charged organic contaminants to the same extent.

Laboratory column studies were conducted on water-saturated quartz sand for investigating the influence of colloids on the transport of metoprolol (MTP), a β-blocker with an acid dissociation constant (pK_a) of 9.6, under varying pH and ionic strength conditions. The experiments were carried out at pH 3, 6, and 11, with sodium concentrations of 1 and 100 mmol L^–1. Experiments were conducted with and without 0.5 g L^–1 Na-montmorillonite colloids (diameter: 100–1000 nm). The results show that the presence of colloids increases the transport velocity of MTP, particularly at pH 6 and low sodium concentrations, indicating colloid-facilitated transport as the primary mechanism. Upon reducing the pH, the magnitude of colloid-facilitated transport decreases, but the bimodal breakthrough curve still suggests some co-transport of MTP. At pH 6 and high sodium concentration (100 mmol L^–1) and pH 11, where MTP is predominantly uncharged, the presence of montmorillonite did not significantly impact the transport of MTP.

These findings highlight the dependence of MTP transport on the existence of clay colloids, salt concentrations, and the speciation of the contaminant determined by water pH. Thus, considering these variables is crucial for accurately predicting the mobility of positively charged organic contaminants in groundwater.

Groundwater in Niger represents an essential resource for survival in remote areas far from the Niger River and a reserve in areas where access to surface water is secured as in Niamey itself. The monitoring of this resource offered as a part of the technical cooperation with the Niger Basin Authority NBA enabled to obtain data on groundwater quality and observe changes in groundwater levels over the last decade. The monitoring targeted the three main aquifers existing in the area: the alluvial aquifer, the Continental Terminal aquifer and the fractured basement aquifer. Several boreholes in the first and second aquifers show high concentrations of NH₄, NO₂ and heavy metals. The boreholes belonging to the third aquifer show concentrations of NO₃ considerably exceeding the WHO recommendation value between 100-1500 mg/l making this resource unfit for water supply. Reasons behind these excessive levels were mainly explained through the direct discharge of wastewater which is common in the Sahel region into the underground. However, the increased concentrations of NO₃ in some wells during the rainy season imply a source in the unsaturated zone which mobilizes the nitrate during the infiltration.

In addition to nitrate, elevated concentrations of heavy metals such as arsenic and cadmium were detected in the basement aquifer proving the possible infiltration of contaminants from the top layers.

These results show that the monitoring tools offered within the technical cooperation framework enable to detect and trace the contaminants. however, they alarm the authorities to meet measures to protect this resource urgently.

The project “Groundwater Quality Monitoring Network Improvement 2021/2022” aimed to assess and improve the groundwater quality monitoring network of the Environmental Agency of the State of Brandenburg, Germany. This comprised six major steps:

1. Developing a catalogue of criteria for verifying the suitability of monitoring wells for representative groundwater sampling and for fulfilling specific reporting duties of the Environmental Agency (considering best practices)
2. Assessing the currently active monitoring wells regarding the suitability criteria
3. Reviewing the monitoring network in each groundwater catchment area regarding its capability to fulfil the different reporting duties
4. Identifying deficits in the network and researching further existing suitable monitoring wells in focus areas, e.g. from the Environmental Agency’s water level monitoring network or from district authorities’ networks
5. Testing the researched monitoring wells on site
6. Suggesting locations for constructing new monitoring wells where no suitable wells exist

A total of 936 active monitoring wells have been assessed. These results have been aggregated for 63 groundwater catchment areas as basis for the deficit analysis. 10 focus areas have been identified for researching and testing existing monitoring wells and for suggesting new sites.

One major project outcome is a three-page factsheet for each catchment area including detailed information on land use, hydrogeology and available monitoring wells as well as statistical analyses of the monitoring well distributions and their suitability. It also contains a prioritised list of measures (adding existing wells to the network, high and low priority new locations) to implement in the next years.

Soil moisture is a key metric to assess soil health. Water held in the shallow subsurface between soil particles enables various biogeochemical and hydrological processes indispensable to soil functions. Potential soil moisture deficit may rise the irrigation demands, which further exacerbates the stress on the water supply. The changes in soil moisture can impact climate, further amplifying the climatic anomalies and intensifying extreme weather events. Thus, understanding soil moisture and its dynamics over time are of broad scientifical interest and practical implications.

Despite the vital importance of soil moisture, it still lacks sufficient means to properly assess the parameter at a regional scale, which is an essential research dimension for addressing practical issues in the agricultural and environmental sectors.

Ambient noise seismology provides new possibilities to infer subsurface changes in a real-time, non-intrusive, and cost-effective manner. In this study, we map the temporal variations in soil moisture for the great Alpine region and the Italy peninsular with ambient seismic noise. It is the first time that the seismic method has been applied to map water resources at a regional scale using an ordinary national seismic network set-up. The seismic method helps in bridging the resolution gap between current pointwise (e.g., tensio-, electrical- and neutron-meter) and global (e.g., satellite-based remote sensing) investigations, providing complementary information for both scientific research and public decision-making.

The waterworks Briesen supply drinking water for the city of Frankfurt (Oder). The catchment of the waterworks is dominated by monoculture pine forests (Pinus sylvestris). Several forest-hydrological studies found that groundwater recharge under pine forests is lowest in comparison to other forest types. Hence, the question arose if forest restructuring could contribute to secure the drinking water supply of the region in the context of climate change and decreasing groundwater recharge.

Site classes of the forestry mapping were researched for all relevant forest restructuring areas. The Ministry of Environment of the State of Brandenburg published a recommendation of tree species mixtures which are suitable for the local conditions and for resisting climate change. Based on this recommendation, five tree species were selected. The tree mixture was set as percentage of these five tree species for each forest site class in the catchment.

The groundwater recharge below five tree species was calculated in a soil-water-balance model separately. Then the groundwater recharge was calculated for the forest site classes based on the percentage tree composition of each site. Finally, several scenarios of forest restructuring were developed, considering complete and partial restructuring as well as climate change. The resulting distributions of groundwater recharge were assigned as boundary conditions in a groundwater model.

The simulations with the groundwater model show that forest restructuring can increase groundwater recharge compared to current forests by 20 - 30 % and reduce the groundwater level decline and catchment expansion which is expected in the context of climate change.

The waterworks Lindau (Zerbst) are an important part of the interconnected system of drinking water supply in the region of Magdeburg, Saxony-Anhalt, Germany. The pumped water is exclusively fed by groundwater recharge. Measured groundwater heads show a continuous climate-induced decline of more than 3 meters for the last 50 years independent of waterworks management.

As basis for strategic planning of future waterworks management and optimization of the monitoring network, groundwater model based studies with climate projections were carried out. For this purpose, an approx. 1,200 km² transient groundwater flow model was set up. The present recoverable groundwater resources and their development in the catchment area until the year 2100 were modelled under changing climatic conditions. The underlying climate scenarios (RCP 2.6, RCP 4.5 and RCP 8.5) are based on the current state of global and regional climate research.

Available climate projections were statistically evaluated for the model domain. A bias correction for precipitation and evapotranspiration was applied and groundwater recharge was calculated transiently for each projection up to the year 2100 using a soil water balance model. This revealed a wide range of potential changes in groundwater recharge. The change ranges from about -35% to +50% by 2100 compared to the 1975-2020 period. The wide range results from high uncertainties of projected precipitation and spatial as well as temporal distribution patterns of precipitation.

The investigations show that in the long term further considerable changes in groundwater resources and hydrodynamics in the catchment are to be expected.

The Luneplate in Bremerhaven consists largely of nature reserves and bird sanctuaries. The soils have a thick alluvial clay horizon. Climate change threatens the region through seasonal heavy rain events, but also through the drying out of clay soils and the spread of saltwater inland due to rising sea levels. The region has traditionally been primarily agricultural, and in the northern part there is an economic area that will be complemented by a carbon-neutral GreenEconomy Park.

The planners of the new business park want to take various measures, including the use of excess rainwater, the creation of compensation areas and infiltration basins to drain surface water. This should also prevent the organic-rich alluvial clay from drying out, reducing the risk of higher CO2 release. This pilot project on the Lune Plate will explore, as part of the Interreg Blue Transition project, how the region can be made more climate resilient through targeted groundwater management measures that are already planned, as well as new measures such as infiltration wells. Infiltration wells can reduce saltwater intrusion and dissipate heavy rainfall. A high-resolution 3D groundwater model is used to simulate the effects of these measures and estimate their impact on climate resilience. The aim of the project is to enter into a dialog with investors and project managers in order to realistically assess the impact of measures and make a meaningful contribution to climate resilience.

The groundwater is a main issue in sustainable development of the Sinai Peninsula, Egypt. Because of extensive groundwater abstraction, the Quaternary coastal aquifer system in the study area is now facing a serious salt water intrusion problem. Seleem (1996) has developed a saltwater intrusion numerical model by using MOCDENCE software which is developed by Sanford & Kinikow (1985). He found that the saltwater intrusion increases the salinity of groundwater in the wells over time. The isohytal map of Sinai Peninsula also shows that the isohyetal contour lines increase towards the northern direction in the Northern Province of Sinai peninsula where the annual rainfall rate is 104.7 mm/year at El-Arish station and 304.1 mm/year at Rafah station.

In the presented study, we suggest a network of rainfall harvesting units to collect the amount of high intensity rainfall water from the cities in the study area. The harvested rainfall water could be injected in the frame of a managed aquifer recharge (MAR) project into the calcareous sandstone (Kurkar) aquifer to attenuate the salinity of this aquifer and to prevent the progress of freshwater-saltwater interface.

For the suggested scenario, the SEAWAT software is applied to simulate the three dimensional variable density groundwater flow and solute-transport in the Quaternary aquifer system in the northern Sinai, Egypt. SEAWAT was developed by the USGS based on MODFLOW and MT3DMS packages. The numerical study with the SEAWAT software allows to investigate the potential impact of MAR on the movement of freshwater-saltwater interface in the study area.

The study area, Erbil Central Sub-Basin, is located within the foothill zone in the stable shelf tectonic unit of Iraq (northern Iraq) on the Arabian plate. Recently, groundwater demand has increased significantly due to insufficient surface water resources for agricultural, industrial, and domestic water uses depending on ever-increasing socio-economic development and population in the study area. Sampling studies were carried out in two different periods, May 2020 (wet season) and September 2020 (dry season), to determine the water quality in water resources located throughout the sub-basin. For this purpose, a total of 30 samples, including 27 groundwater wells, and 3 wastewater samples from channels, were collected and analyzed. The general hydrochemical analysis indicates that overall well water quality is suitable for drinking purposes except where elevated NO₃, COD, and BOD5 concentrations are found. Most trace metal analysis results (except for Fe) in wells and wastewater channels show that they are below the permissible limits (0.3 mg/L) from IQWS (2010) and WHO guidelines (2011). The results of the factor analysis for the wet and dry season hydrogeochemical indicate that the first five and six-component extracted have eigenvalues>1 and correspond to approximately 94.844 and 96.26 % of the total variance, respectively. The factor analysis indicated that groundwater quality in the wet and dry season are significantly associated with anthropogenic pollution sources such as leaching from soil layers, cesspools wastes, industrial wastes, and agriculture activities rather than natural, geogenic processes such as reverse ion exchange, the weathering of carbonate minerals from geologic formations outcropping throughout the Erbil Central Sub-Basin.

The Kallar Kahar area falls in the sub-Himalayas. The structural geometry of the area has been assessed using geological mapping and structural analysis. At the surface the study area comprises of the rock units ranging in age from Precambrian to Pliocene with several major unconformities. The Precambrian Salt Range Formation is exposed in the form of diapiric intrusions. The strike slip Kallar Kahar Fault (KKF) controls the structural fabric of the area. It is a NW-SE trending structure characterized by an overall transpressional tectonics with a right lateral strike slip component. An en echelon pattern of NW-SE trending folds, a back thrust and a couple of fore thrusts occurs in the immediate south of the Kallar Kahar Lake. These thrusts are out of sequence thrusts cutting up section the thrust sheet of the Salt Range Thrust (SRT). The fore-thrusts represents a relatively younger phase of deformation than the back thrust as the former cross cut the later one. These folds and faults formed as a result of transpression associated with a left step over along the KKF. The rigorous compressional structures in the southeastern portion of the mapped area, and a clear discontinuity on the Landsat images are in line with the presence of a left step over along the KKF. The restraining along this stepover during ramping along the SRT, resulted in salt diapirism in the area. The KKF is believed to have formed to accommodate the variable stresses generated during the differential propagation of the SRT’s thrust sheet.

Tridacna shells feature macroscopically visible bands (at mm scale) as well as microscopically visible daily banding (at µm scale). To evaluate the lifespan of an individual, the presumably seasonal macroscopically visible bands can be counted, or stable oxygen isotope analysis can be used to identify seasonal cycles. However, these approaches may not always be conclusive, especially for Tridacna which at times display irregular seasonal growth patterns and often grow in equatorial areas with low seasonal SST variability and heavy seasonal precipitation, influencing δ¹⁸O seawater values. Counting the daily bands (manually or with software-based image analysis) gives a more accurate internal age model with high temporal resolution, but daily banding is not always visually retrievable in fossil specimens, hampering the production of a precise age estimate. We show that daily geochemical cycles can be measured with highly-spatially resolved laser-ablation inductively coupled plasma mass spectrometry (LA-ICPMS; 3 x 33 µm laser slit) in our Miocene (~10 Ma) specimen, even in areas where daily banding is not visible. We present a python script Daydacna, in which we use wavelet transformation on the measured daily geochemical cycles to quantify varying daily growth rates throughout the shell. This provides a robust alternative to visual band counting. The resulting age model can be used to quantify seasonal growth rate variability over several decades and provide a basis for time resolved sub-seasonal paleoenvironmental proxy evaluation.

The aim of the research was to produce a microbiologically safe, modified mineral material with increased sorption parameters, enabling use in the cosmetics industry as an active substance in the line of dermocosmetic products. Samples of selected kaolin (from the Jegłowa deposit, part of Silesia, Poland) were subjected to thermal (at 600 ℃) and chemical activation (using 2 or 4 M HCl). The modified material was characterized using the XRD, SEM and gas porosimetry methods (the specific surface of the samples was determined based on the assumptions of the BET model). The microbiological purity of the newly manufactured materials has been tested in accordance with the applicable standards ISO 21149:2017-07 (for bacteria) and ISO 16212:2017-08 (for yeasts). The results showed that both modifications affected the structure and properties of the tested samples. The acid activation caused the displacement and increase in the intensity of XRD reflections of kaolinite, which is the result of the removal of poorly crystalline mineral phases from the sample, present in unmodified samples. SEM imaging confirmed the change in the morphology of kaolinite plates. The measured surface properties of the samples (specific surface area, micropore area) were significantly higher in the case of acid activation and increased with the use of a stronger acid (4M HCl). Microbiological tests have shown that both the thermally and acid-activated samples meet the quality requirements for materials used in the dermocosmetics. The conducted research proves that kaolin from Jegłowa can be an attractive raw material for the cosmetics industry.

Leaf-wax n-alkane concentrations and average chain lengths (ACL) significantly vary among extant gymnosperm groups. When investigating deep-time archives, further plant groups need to be considered that since went extinct. Also, entirely aquatic plants, as known in the angiosperm clade, are not known to be amongst any fossil or extant gymnosperm group. The Middle to Late Jurassic macroplant assemblage preserved in the volcanic lake deposits of the Haifanggou Formation in Inner Mongolia, China, and attributed to the Yanliao Fossillagerstätte, reflects such a gymnosperm-dominated environment, amongst which the extinct Bennettitales constituted the dominant seed-plant component, with ginkgophytes and cupressoid conifers as additional major components. This fossil environment existed c. 35 million years prior to the rise of the angiosperms. The current study examines the relative n-alkane concentrations preserved in 33 samples from two excavations in the Haifanggou Formation. Despite the high age of the sampled strata, n-alkane preservation is excellent. In addition, the two excavations yield mean ACL_25–37 values of 28.2 and 27.8, respectively, and the n-alkane distributions are dominated by n-C₂₇ alkanes and, in some samples, by n-C₂₅ alkanes. Thus, given that Bennettitales were the dominant plant group in the assemblage, we hypothesize that bennettitalean cuticles were composed of n-alkanes with relatively short chain lengths compared to extant gymnosperm groups. To corroborate this hypothesis, further verification through direct analysis of well-preserved fossil cuticles of Bennettitales is warranted.

The Little Ice Age was a period of colder climate and extended glaciation mainly observed in Europe and North America between the middle of the 14^th and the end of the 19^th century. However, the climatic impact of the Little Ice Age on tropical regions is still unclear. In this study, we sampled two short (1m), dated sediment cores (MJ17-01A-G and MJ17-01B-G) that were taken in 2017 within Lake Maninjau for leaf wax compound-specific analysis. Lake Maninjau is a 99.5 km² caldera lake located at the equator in the Padang Highlands on the Island of Sumatra, Indonesia. Here, we extracted leaf-wax compounds of 34 samples – so called n-alkanes – measured their concentration and calculated the average chain length (ACL) and carbon preference index (CPI) of the individual samples. The ACL is a first-order proxy for overall humidity/precipitation and ranges between carbon numbers of C₂₆ and C₃₁ with a trend to lower values towards the top of the section. We interpret this shift from higher to lower ACL-values to represent a shift from dryer to more humid conditions between 1550 and 1850 AD in the period of the Little Ice Age and into the modern. We interpret that the Little Ice Age in Europe and North America indeed also affected tropical regions like Southeast Asia.

Rare earth elements (REE) are essential for various modern "green" technologies. However, conventional mining and extraction methods for REEs are energy-intensive, environmentally harmful, and call for the evaluation of alternative extraction procedures for these critical raw materials. Bioleaching processes have been successfully employed in the industrial extraction of metals and offer a promising and eco-friendly approach to enhance the sustainability of REE extraction. This study evaluates the potential of bioleaching REEs from unprocessed carbonatitic and alkaline bulk rocks.

Batch and supernatant leaching experiments were conducted on a Carbonatite sample from the Fen-Complex (Norway) and two nepheline syenites (a Grennatite and a pegmatitic Grennaite from Norra Kärr, Sweden), utilizing the heterotrophic organisms Yarrowia lipolytica and Tea fungus Kombucha. The influences of bulk mineralogy on microbial growth and metabolite production, as well as leaching rates and applicability of the different approaches were assessed.

The results demonstrate varying recovery rates based on mineralogy and leaching methods, with preferential leaching of light or heavy REEs depending on the selected organisms. Notably, the highest leaching efficiency of 54% REE recovery was achieved with Y. lipolytica supernatant leaching on pegmatitic Grennaite during a 19-day experiment. Carbonatite and Grennaite samples exhibited lower maximum leaching rates of 5% and 8%, respectively.

The findings demonstrate the proof-of-concept feasibility of bioleaching REEs from unprocessed bulk rock materials and highlight its strong potential, especially in providing a sustainable solution for utilizing low-grade ores and mine waste.

Determination of particle size distribution of sediments and soils is a crucial property in several fields of industry and geoscientific research. The consequence of improper analyses can result in poor product quality, high rejection rates, or incorrect research data.

Most currently used particle sizing methods such as laser diffraction, sieve analysis or microscopy, are established over decades or even centuries and have been deployed in many different fields. However, their significance is often limited due to low resolution, limited capabilities in terms of quality control requirements or simply the lack of particle shape information. The concept of imaging particle analysis is a relatively new technology, dating back to the late 1970s as CCD sensors for capturing and computers for processing image data began to evolve. Further developments such as Dynamic Image Analysis (DIA) based on one or two high-speed cameras provided enhanced access to morphological particle size and shape information in high-resolution and with statistical robustness by a simple measurement of usually less than three minutes.

Here we introduce two new technologies in the context of dynamic image analysis. Designed as a hybrid-laser diffraction particle-analyzer, the Microtrac Sync provides conventional laser-based optics, equipped with a digital camera for precise particle size and shape information.

Another ground-breaking technology comes with the new Camsizer3D. It uses particle tracking technology, allowing to follow each particle of a sample in up to 30 different orientations. The resulting high-resolution 3D dataset provides digital size and shape information of real morphological particle geometries.

A major goal in exoplanet science is the search for planets with the right conditions to support liquid water. The habitability of a planet depends strongly on the composition of its atmosphere. Interiors and atmospheres of rocky planets are linked through feedback processes and evolve as a coupled system. In particular, volcanic outgassing shapes the atmospheric composition, but the exact composition of outgassed species not only depends on the volatile content and redox state of the mantle, but also on the current state of the atmosphere.

In an extensive parameter study of rocky exoplanets, we investigated the emergence of habitable surface conditions for a wide range of initial conditions, including the planet mass, interior structure, volatile content and redox state. The model accounts for the main mechanisms controlling the long-term evolution of stagnant-lid rocky planets (i.e. bodies without plate tectonics). It includes a large number of atmosphere-interior feedback processes, such as a CO2 weathering cycle, volcanic outgassing, a water cycle between ocean and atmosphere, greenhouse heating, as well as escape processes of H2.

We find that only a narrow range of the mantle redox state around the iron-wüstite buffer allows forming atmospheres that lead to long-term habitable conditions. At more oxidizing conditions, most planets instead end up in a hothouse greenhouse state (akin to Venus) due to strong CO2 outgassing. On the other hand, on planets with more reducing mantles, the amount of outgassed greenhouse gasses is often too low to keep the surface above the freezing point of water.

Internal heating in rocky bodies shape their interior and surface characteristics as well as their evolution. Among internal heat sources, tidal dissipation is a key one. The most striking evidence in the Solar System is the case of Io, archetype of tidally-heated world hosting extreme volcanism.

Io’s internal dynamics is complex due to the large and tidally-produced heat flux, leading to widespread melting in the interior. For Io-like bodies, the dissipation and heat transport models have thus to incorporate interactions between solid and liquid phases. Io’s mantle is commonly modelled either as a solid convective mantle, adapting models of terrestrial planets, or as a fluid magma ocean, adapting models of fluid water oceans of icy moons. However, neither of these two classifications likely accurately describes Io’s partially molten interior.

In that context, we model Io's mantle thermal evolution following the work of Sanchis et al (2022, EPSC), who developed a magma ocean modelling, using the CHIC convective code (e.g. Noack et al. 2013, Infocomp). In addition, we take into account heat generated by tidal dissipation accounting for the effect of melt presence on the viscous and elastic parameters of the mantle following Kervazo et al. (2021).

Our study provides valuable insights into the role of a large amount of melt in the thermal evolution of rocky planets and moons, and our modeling approach is applicable to other rocky planets with hot interiors, including the Trappist-1 planets and various known rocky exoplanets.

On 26^th of September 2022, NASA’s DART spacecraft impacted the secondary of the Didymos system, Dimorphos [1]. Its impact shortened the orbit of Dimorphos by 33 minutes to 11.37 h [2]. The change of the orbit is caused by a change of Dimorphos’ momentum due to the impact. A fraction of the momentum-change related to the transfer of the spacecraft momentum. The more important fraction of momentum is caused by the ejection of material from Dimorphos. The momentum-enhancement-factor β for vertical impacts is defined as β=1+p_Ej/p_Imp, with the ejecta and impactor momentum p_Ej and p_Imp, respectively, and was predicted to fall between ~2 and 5, based on impact simulations into homogeneous materials, [3,4,5]. The estimates for β depend on Dimorphos’ properties. For a density of 2400 kg/m³, the estimate is β = (1σ) [6]. Recent studies have shown that heterogeneities in the target (e.g. boulders) affect material ejection and β [7, 8]. In this study, we use impact models to simulate the DART impact with 1-10m-sized boulders, and we test the influence of a potential stronger and denser subsurface layer on β. We find an increase of beta by ~5% for such a subsurface layer in 5m depth, so that we conclude that heterogeneities in >5m depth do not affect β.

We acknowledge the computing time provided for our project bek00041on the supercomputer Lise and Emmy, part of the NHR infrastructure.

[1]Daly et al.(2023),Nature616,443.[2]Thomas et al.(2023),Nature616,448.[3]Raducan et al.(2019),Icarus329,282-295.[4]Stickle et al.(2022),PSJ 3:248.[5]Luther et al.(2022),PSJ3:227.[6]Cheng et al.(2023),Nature616,457.[7]Ormö et al.(2022),EPSL594,117713.[8]Raducan et al.(2022),A&A 665,L10.

Convective mantle flow in terrestrial planets is governed by a temperature- and pressure-dependent rheology. This results in a stagnant-lid regime observed on most terrestrial planets. Plastic deformation can lead to breaking of the strong upper lithosphere, which resembles plate tectonics on Earth. Most efforts to model mantle convection with self-consistent plate tectonics combine Newtonian diffusion creep with a stress-dependent pseudo-plastic rheology in the form of a yield criterion. However, in the uppermost mantle, where stresses are high, deformation is thought to be driven in large parts by deformation via dislocation creep. As numerical models get more robust and capable of more complexity, viscoplastic models should therefore include non-Newtonian dislocation creep.

In our models we employ a composite viscosity, combining both Newtonian and Non-Newtonian power laws in a viscoplastic approach. We study the influence of varying rheologies on plate tectonics simulations, by testing several internal and external parameters, such as grain size and surface temperature. In a 2D-spherical annulus geometry we employ an interior structure model for an Earth-like planet to obtain local information on thermodynamics properties of the main minerals present in Earth’s mantle. We evaluate the models by computing common diagnostic values used to recognize plate-like surface deformation. The goal of this study is to identify key planetary factors for the occurrence or absence of plate tectonics.

The Cenozoic of Borneo consists of thick clastic sedimentary rocks that were deposited in various fluvial-lacustrine, shallow marine and deep-marine settings. From the Eocene onwards, the sedimentary successions play an important economic role. Onshore, Eocene sediments comprise coal seams of commercial interest, while Miocene deposits offshore are important hydrocarbon reservoirs. In principle there are two main sediment sources that have contributed to the successions. The Cretaceous arc-related Schwaner Mountains in the south of the island, and the Triassic tin belt granites from the Malay Peninsula. Characteristic detrital zircon U-Pb ages and heavy mineral signatures reveal a change of these sources through time, related to major tectonic developments, such as the opening of the South China Sea. The Miri Zone in NW Borneo consists of Eocene turbidites of the Rajang Group, unconformably overlain by tidally-influenced delta deposits of the Oligocene Nyalau Formation. The Rajang Group turbidites overall reveal a provenance related to the Schwaner Mountains, while the Nyalau Formation indicates a Malay tin belt source, bypassing southern Borneo. The Miocene deposits of the Baram Delta form the youngest successions of the Miri Zone, and comprise fluvial, tidal, deltaic and shallow marine deposits. They are the analogue for the hydrocarbon reservoir offshore Brunei and northern Sarawak. In contrast to the underlying Nyalau Formation, the Baram successions were sourced directly from uplifted Rajang Group tubidites from the interior of Borneo. Thus, studying compositional variations and provenance characteristics help to understand sources and sedimentary routing pathways.

In the Badenweiler-Lenzkirch Zone (BLZ) of the southern Black Forest, lower Paleozoic metasedimentary rocks of the Sengalenkopfschiefer Formation contain intercalations of diamictites which have been linked to the Hirnantian glaciation. This interpretation is based on lithological arguments and rare palynological remains showing Ordovician to Devonian Acritarch and Chitinozoa associations. This interpretation is challenged by new results of U-Pb dating of detrital zircon grains from four samples of diamictites and associated fine-grained schists. The diamictite layer consists of strongly elongated clasts up to 5 cm in diameter, comprising vein quartz, volcanic detritus, pelites, and minor magmatic pebbles. In total 509 detrital zircon grains were dated by LA-ICP-MS at KIT. These reveal similar age spectra for all four samples, characterized by significant age peaks at ~ 380 Ma, ~ 400 Ma, ~ 480-500 Ma, ~ 600-620 Ma, ~ 700-750 Ma and ~ 1.8-2.2 Ga, and ~ 2.6 Ga, and very small peaks at 0.9-1.1 Ga. The pre-Silurian age populations correspond to the spectra of West Gondwana with minor Mesoproterozoic and very minor Grenville zircons (ca. 1.0 Ga). The two younger age populations fit to a subduction model with an active magmatic arc and published ages for the adjacent Randgranite nappe. The youngest zircon grains reveal maximum depositional ages of ca. 360 Ma, which is close to the Devonian-Carboniferous boundary. This discards the former assumption of Hirnantian glaciation. Instead we hypothesize that the diamictites are linked to the Upper Devonian glaciation which affected North America, South America and West Africa.

As we are risking to exceed the 1.5-degree target in the next decade, effective measures to cut back greenhouse gas emission are necessary. Methane became the focus of attention as the target to mitigate global warming, since the mean atmospheric lifetime of this strong greenhouse gas is at least an order of magnitude shorter than carbon dioxide. Here we will focus on the oil and gas sector, which represents the second largest anthropogenic methane source after agriculture. Abandoned oil and gas wells are seen as important targets, since they can (in some cases) emit up to several tons of methane per day. However, only about a dozen countries have measured data on methane emissions and even less include it in their yearly greenhouse gas inventory. Germany has about 20,000 abandoned wells, which are generally filled and buried, however, it is unclear, whether they are emitting methane or not.

Here, we present an overview of methane emission and microbial methane turnover at about 50 onshore oil and gas wells in Northern Germany covering both abandoned exploration and production wells. Using isotopic methane composition we were able to link the methane emissions at three well sites in an active peat-cutting area to methanogenesis. Furthermore, elevated potential methane oxidation rates suggest that the majority of the microbially formed methane was oxidized before reaching the atmosphere. Our data demonstrates the necessity for detailed knowledge on methane cycling and background emissions to assess abandoned wells, particularly in areas where natural methanogenesis is present.

Inverting forward models to constrain output against data is critical for predicting and understanding sedimentary systems. We present an open-source workflow using SciPy functions to invert a Python Badlands model with spatially variable tectonic and rainfall parameters.

Tectonic uplift and rainfall maps are input to model surface uplift, erosion, transport and sediment deposition across the model grid. A SciPy function optimises against an objective function to calculate error and invert the model to find the optimal tectonic and rainfall parameters required to reproduce key aspects of the observed strata.

The workflow has four steps:

1. Collate paleoDEM’s, paleogeographic, thermochronological and climatic data to create initial topography, tectonic uplift and rainfall input maps

1. Run the Badlands forward stratigraphic model to calculate evolving topography and basin-fill strata

1. Use an objective function to calculate error from the comparison of model output and observed stratal properties

1. Use SciPy to iteratively optimise parameters through steps 2 and 3 to minimize model error

This approach generates a useful series of best-fit models for the Bengal Fan source-to-sink system. The nature of the objective function reveals important aspects of the model behaviour and indicates that climatic factors increasing erosion and sediment yields were the main forcing of Miocene deep-water sedimentation in the Bengal Fan.

The Kuboos-Bremen Line (KBL) is an alignment of intrusions that extent for 250 km in South Africa and Namibia. Its deepest exposed parts occur near Alexander Bay (RSA) and it continues into the continent trending SW-NE, with the higher intrusion level at the Great Karas Mountains (NAM).

The KBL complexes are divided in three sections: Western KBL is predominantly granitic; Central KBL is composed of granites, syenites, foid-syenites and carbonatites; and Eastern KBL is composed of a field of more than a hundred small carbonate-bearing intrusions (carbonatite dykes, sills and breccia pipes, and lamprophyre and alnöite dyke swarms).

The project aims to understand the genetic relationship between the variety of lithologies at the KBL by: investigating whether the behavior of HFSE and REE in carbonatitic magmas is influenced by source contamination and silicate wall-rock interaction; investigating the cross-cutting relationships of individual complexes and their age data, to understand the progressive evolution from granitic to foid-syenitic/carbonatitic compositions with time and location; and study the rock associations to establish if different magma suites derived from one or variable sources and also if they used the same zone of weakness for ascent and emplacement.

After field work and sample collection from all main complexes the first results from geological mapping and petrography show an even broader variety of lithologies than expected. Individual units from individual complexes share textural and mineralogical similarities and also provide us hints of the role of crustal assimilation in the genesis and magmatic to hydrothermal evolution of these rocks.

The Mesozoic to Cenozoic intraplate to rift-related magmatic activity in central Europe spawned both, intrusive and extrusive carbonatites. Located within the intersection of the Regensburg-Leipzig and Gera-Jachýmov fault zones, the eroded diatreme of Ebersbrunn provides a unique opportunity for mineralogical and petrographic investigations to explore the magma genesis and its lithospheric evolution. Electron microprobe analyses on several mineral phases were acquired to obtain thermobarometric estimations and unravel the internal textures. Moreover, detailed microscopic studies on juvenile fragments are used for the characterization of volcanic facies. Here, the compositional variation in amphibole (with Mg# from 0.804 to 0.932) and mica (Al-rich phlogopite and eastonite) can be linked to the presence of lamproite components in the generation of supplying magma system and show a multi-episodic crystallization history. Thermometric estimations for the carbonatitic magma showed a wide range from 450 to 672°C (obtained on low- and high-Mg calcite and dolomite). The joint presence on high-T amphibole (872 to 965 °C) and mica ( ca. 950 °C) suggests the contemporaneous crystallization from a single magma storage and the presence of mid-crustal magma storage at 15 to 21 km.

The petrographical studies on circular/ ellipsoidal juvenile fragments revealed different populations of peletal lapillis, with either dry or wet silicate, Fe-Ti-oxide, and/or carbonate phases in the kernel and a carbonatitic and/or silicic shell composition. This indicates the influence of hybrid magma and emphasizes the multi-stage layering process. The oriented prolate-shaped apatite crystals at the rim of pelletal lapillies are addressed to turbulent motion during magma ascent.

The Eocene (49 Ma) Dicker Willem carbonatite complex represents an “Inselberg” (5 km²) forming a subvolcanic intrusion in southern Namibia. It consists of several stages of carbonatitic intrusions including, alvikite, sövite, nepheline sövite as well as carbonatite breccia. Associated silicate rocks (ijolite and nepheline syenite) are rare but found as xenoliths of various sizes embedded in carbonatite (sövite and alvikite). To decipher the genetic relation between carbonatites and silicate rocks and the formation of nepheline sövite (which is seen as a transitional lithology), we investigated a center-margin profile within a silicate-rich carbonatite xenolith (Ø 7 m) enclosed in fine-grained calcite-carbonatite (alvikite). Detailed observations show systematic mineralogical and mineral chemical variations depending on the contact proximity. Multiple element diffusions and transformation reactions can be traced. Mineralogically, feldspathoids are increasingly replaced by K-feldspar. Secondary biotite crystallized at the expense of feldspar and clinopyroxene close to the contact. Clinopyroxene compositions develop from a Ca (Mg, Fe) dominated to a Na (Fe) bearing variety. Excess iron (Fe³⁺) not being incorporated in biotite crystallized as hematite. With closer proximity to the host rock the dominant mineral within the xenolith becomes calcite (up to 95 modal%). These besides other indications suggest that a magmatic replacement of a silicate xenolith resulted in the successive transformation into a carbonatite, that is barely distinguishable from a coarse grained sövite. This process thus reflects the origin of the nepheline sövites rather than the liquid immiscibility that was thought to follow the genetic link between silicate rock and carbonatite at depth.

The examination of more than 500 samples of worldwide carbonatites on the basis of Sr-Nd isotope systematics allows dividing them into three groups which do not follow conventional grouping. Carbonatites with a mantle signature and variable amounts of incorporated sedimentary material form the first two groups. The carbonatites in the third group have resolvedly lower ¹⁴³Nd/¹⁴⁴Nd signatures at a given e_Sr(i) value that cannot easily be explained by crustal contamination but rather by derivation of carbonatite parental melts from the mantle source metasomatized by 2-6% of slab-derived melts with low Sm/Nd during the late Archean (~2.7 Ga).

As a consequence of high concentrations of Sr and Nd, this system is more resilient to overprint compared to Re-Os elemental and isotope systematics. Overall, 44 carbonatite samples were investigated for Re–Os compositions; of these, 15 samples were excluded due to modification by late-stage hydrothermal alteration. The remaining carbonatites still yield a wide range of gOs from ~4 to 4000. Whether this wide range is a result of the presence of recycled crust or originates from previous carbonatite metasomatism remains unclear.

Extremely low concentrations of highly siderophile elements (HSE) in carbonatites and common nugget effects observed are the result of the behavior of sulfur-bearing phases as the main HSE carrier and oxygen fugacity. Carbonated silicate melts are capable to host significant amounts of PGE but during ascent, S-rich magma will separate from carbonatite melts leading to the sequestration of PGE due to higher distribution coefficients, leaving carbonatite melt depleted in PGE.

Strong local REE enrichment is observed in Mesoproterozoic ankerite carbonatite exposed at Swartbooisdrif, NW Namibia (Drüppel et al., 2005). The carbonatite dykes transect older anorthosites of the Kunene Complex and are themselves surrounded by sodalite-rich Na-metasomatic aureoles. The magmatic assemblage of ankerite, magnetite, pyrochlore, burbankite, and apatite indicates that the carbonatite magma was rich in Fe, Nb, P, Na, Sr, and LREE. Primary REE hosts are euhedral burbankite, pyrochlore, and apatite, which can be enriched in irregular layers formed during flow-banding.

Along cracks burbankite is altered to secondary burbankite and carbocernaite. With progressive alteration, burbankite and carbocernaite were partially to completely replaced by complex intergrowths of fluorcarbonates (mainly bastnaesite, hydroxylbastnaesite, parisite and synchysite), ancylite, monazite, barite, strontianite, celestine, calcite, fluorapatite, and/or hematite. Similar mineral assemblages also occur as discrete REE-rich pods and schlieren, suggesting fluid-related remobilization of REE and P. These zones are mainly restricted to the ankerite carbonatite, indicating locally restricted REE mobility.

The composition of early metasomatic and later hydrothermal fluids was determined by microthermometry and synchrotron-micro-XRF analysis of primary fluid inclusions in sodalite and secondary fluid inclusions in ankerite. Early high-temperature (> 550°C) sodalite-forming fluids were highly saline alkaline brines (19-30 wt% NaCl eq.) containing minor Sr, Ba, LREE, Nb, S, K, and Fe. Secondary fluid inclusions in ankerite, entrapped at lower temperatures of c. 400-500°C, are NaCl-poor (4-6 wt% NaCl eq.) and strongly enriched in Sr and REE. These fluids are presumably related to the late REE remobilization.

Drüppel et al. 2005, J. Petrol., 46, 377–406.

The Chatham Islands, situated on the eastern Chatham Rise ~800 km east of New Zealand, comprise two main (Chatham and Pitt) and many smaller islands. Collision of the oceanic Hikurangi Plateau with the Chatham Rise jammed the long-lived subduction system, causing Zealandia to separate from Gondwana. The breakup was accompanied by volcanism on the South Island of New Zealand, Hikurangi Plateau (Hikurangi seamounts) and Chatham Rise and islands, many of which were formed by the volcanism. The Late Cretaceous volcanism is characterized by HIMU (high time-integrated μ=²³⁸U/²⁰⁴Pb Mantle) endmember composition, which sensu stricto is defined by oceanic islands associated to deep-rooted mantle plumes. Consequently, an heritage of the HIMU source from the lower mantle transferred to the surface by a mantle plume is debated, but numerous alternative models have been proposed to explain the HIMU volcanism in Zealandia, including sub-continental lithospheric mantle modified by subduction or interaction with the partly subducted Hikurangi plateau. Our major and trace element analyses of 52 Cretaceous whole-rock samples from the Chatham Islands display characteristic HIMU trace element compositions, but the major element (MgO vs. CaO) and olivine composition indicate a predominantly pyroxenitic (or phlogopitic) rather than peridotitic source, which is usually associated with HIMU lavas. Further investigation on the composition of primitive melts, melting conditions and source lithologies will be used to evaluate the potential role of a mantle plume causing HIMU end member volcanism and separation of Zealandia from Antarctica in the Late Cretaceous.

The eastern margin of Asia formed an active Andean-type margin from the Triassic until the Cretaceous. SE Vietnam and West Borneo were located at the southern end of this subduction zone. Triassic igneous rocks in Indochina are usually interpreted to be related to the closure of the Paleo-Tethys. However, in West Borneo Triassic I-type granitoids and associated fore-arc volcaniclastic turbidites can be attributed to west-directed subduction of the Paleo-Pacific. The arc can be traced through the South China Sea to SE Vietnam and Hainan with magmatism continuing into the Jurassic, although with a diminished intensity. Thus, West Borneo can be correlated with the Indochina basement. With the beginning of the Cretaceous and docking of the Banda block (which consists of SW Borneo) with West Borneo, large Paleo-Pacific subduction-related magmatic provinces formed in southern Borneo and SE Vietnam. Lower Cretaceous I-type granitoids are thereby dominant in Borneo, while in SE Vietnam Upper Cretaceous I-type rocks are more abundant. At around 80 to 85 Ma magmatism changed from I-type to A-/S-type affinities, suggesting cessation of the Paleo-Pacific subduction and a switch to post-orogenic magmatism that lasted until the end of the Cretaceous. The Mesozoic igneous record of the West Borneo and SE Vietnam provinces is remarkably similar and indicates a common tectonic history associated with the various stages of Paleo-Pacific subduction beneath eastern Asia.

The Muskau Arch (MA) is located in the border area of the federal states of Brandenburg and Saxony and Poland.

The Muskau Arch is part of the main Warthian terminal moraine in Germany. With its U-shaped form, it is the southernmost extension of the Warthe glaciation in Germany. The width reaches c. 20 km and the arc depth c. 22 km.

The morphology of the Muskau Arch is characterized by compression, folding and overthrusting of Tertiary strata. Including special features, such as a multitude of Gieser structures or folded Pleistocene channel deposits. The so-called Gieser (Wendish Jeser/ jezero: swamp) are terrain furrows with a maximum depth of 20 m, a width of 10 m to 30 m and a length of up to several kilometers. Thus they represent a characteristic geomorphological element. They were formed by weathering and oxidation of the tertiary lignite seams, which were folded by glacial deformations.

In addition to these structures, there are further glacial forms in the area of the Muskau Arch, which are partly visible in the morphology and partly can only be mapped as glacial structures by geological exploration.

In this Study glacitectonic structures (i.e. diapirs, rupture structures, folding and faulting) are analysed and reconstructed focussing on scales, depth range characteristic shapes. These structural geological investigations were based on geophysical methods (near-seismic, gravimetry, geoelectric soundings and mapping as well as borehole geophysical measurements).

Formation of Early Permian rhyolites in the Schwarzwald postdates the exhumation of Variscan granites and gneisses. Although similar Permian volcanics are recognized across Central Europe, little is known so far about their source(s), precise ages, magmatic evolution, and later alteration. To answer these questions, we investigated 68 rhyolite samples (lavas, tuffs, ignimbrites, diatremes) from five different localities in the Northern Schwarzwald.

Most rhyolite samples contain phenocrysts of quartz, K-feldspar, and biotite set in a fine grained groundmass rich in secondary illite and hematite. Igneous zircon, monazite, Fe-Ti oxides, apatite, and uraninite are common accessories. All samples are peraluminous high-SiO₂ rhyolites with calc-alkaline compositions. Mantle-normalized trace element patterns show negative Ba, Sr, Eu, and Ti anomalies, indicating plagioclase and Fe-Ti oxide fractionation. REE patterns with LREE enrichment and deep negative Eu anomalies characterize them as hot-dry-reduced rhyolites, typically occurring above areas of mantle upwelling. A likely source are lower crustal dry metasediments.

Secondary alteration is correlated with increases in Al₂O₃, LOI, Li, and As. At one locality, a unique secondary REE-P-As-Th-S assemblage, comprising monazite, gasparite, thorite, xenotime, and galenite, is observed. The As-REE-rich phases presumably originated from alteration of primary monazite, zircon, and apatite by As-rich aqueous fluids.

U-Pb La-ICP-MS dating of igneous zircon, monazite, and uraninite from different localities yields consistent crystallization ages of 296.0 ± 1.3, 297.5 ± 2.9 Ma, and 296.2 ± 1.1, respectively. A later Early Jurassic alteration event is evidenced by U-Pb ages of 181.5 ± 2.1 and 173.5 ± 1.6 Ma determined for secondary xenotime.

The Early Carboniferous Saxothuringian Basin (SXB) is exposed on the northwestern side of the Bohemian Massif in Central Europe. SXB is bordered by the Mid-German Crystalline Zone (MGCZ) to the NW and N, by the Lausitz block and the Elbe Zone to the NE and E and the Tepla-Barrandian to the SE. Basin boundaries are defined based on the structural, metamorphic and stratigraphic observations of the exposed Variscan and pre-Variscan units in the Bohemian Massif. However, to the SW across the Franconian Fault System (FFS), Permian-Mesozoic sedimentary rocks cover the Variscan units including the possible SW extension of the SXB.

In this study we integrate geophysical (gravity, magnetic and seismic reflections) and well data to investigate the SW extension of the SXB and discuss implications for the Variscan tectonics. Our observations and forward modeling results show that the remnant of SXB extends about 60 km to the W-SW from the present-day FFS and terminates near the NE part of the Kraichgau Terrane. We also show that SXB units are most likely preserved below the Permo-Mesozoic units farther south, west of the Fichtelgebirge area. Based on our study, we discuss that the SXB developed as a low-strain and isolated area in the Saxothuringian Zone, receiving erosional material from the surrounding high-strain and uplifted areas during the Variscan tectonics in early Carboniferous, before being overfilled by the Middle Mississippian (Visean) time.

We investigated a SSE-dipping reverse fault zone of the ENE-striking Gernsbach-Neuenbürg flexure within c. 325 Ma old coarse grained two-mica granite. The fault zone consists of a hematized, cataclastic 15-20 cm thick, damage zone, predominantly developed in the hanging wall, and a c. 1 cm thick greyish-greenish clay-rich fault core. We took two gouge samples, spaced c. 1 m apart from each other.

Both samples were fractionated into three grain sizes (<0.2 µm, <2 µm and 2-6 µm), all of which yielded ages between 198 Ma and 171 Ma. The fact that these ages are much younger than the age of the faulted host rock, and that both samples exhibit variations between the different fractions of a few tens of Myr at most, indicates efficient authigenic clay growth. This authigenic crystallization probably occurred between 200 °C and 300 °C, based on the illite “crystallinity” Index and the predominance of the 2M₁ illite polytype in the samples.

The Gernsbach-Neuenbürg flexure plunges to the ENE beneath deformed Triassic strata of the ENE-striking, c. 100 km long „Neckar-Jagst-Furche“, which is yet kinematically poorly understood. Its large strike length and apparent low bulk displacements are consistent with reactivation of the southern boundary fault zone of the Permocarboniferous Kraichgau basin as suggested by mapping of the Gernsbach-Neuenbürg flexure. The widespread Jurassic radiometric age data in southern Germany indicate major hydrothermal activity and a structurally complex, yet poorly resolved, deformation pattern, most likely associated with oblique rifting that developed into formation of the North Penninic ocean.

As demonstrated by the Saxo-Thuringian Ocean, some regional geological models originated prior the advent of plate tectonics and evolved little since. Despite the abundance of facts that neither prove nor need the existence of such an ocean, this plate tectonic scenario is still widely used. The Saxo-Thuringian and Moldanubian zones represent classical areas of the Central European Variscides. The Saxo-Thuringian Zone originally was defined as a narrow marine basin with Paleozoic lithologies overlying a Precambrian basement. Early mobilistic models proposed an allochthonous origin of the Münchberg Massif, representing remnants of the Moldanubian Zone, thrusted onto a southeastern ramp of the autochthonous Saxo-Thuringian Basin. With the advent of plate tectonics, the Saxo-Thuringian Zone was reinterpreted as an independent microplate that is surrounded by oceanic lithosphere. In such a view, the subduction of a so-called Saxo-Thuringian Ocean beneath a Moldanubian microplate is necessary to transport Moldanubian crust onto the autochthonous Precambrian / Paleozoic units of the Saxo-Thuringian microplate. Over the last decades abundant new geoscientific data, including the results of the continental deep drill hole (KTB), challenged the Saxo-Thuringian Ocean hypothesis. Today there exist ample evidence (i) that the allochthonous units of the Saxon Granulite Massif and the Fichtelgebirge-Erzgebirge nappe pile experienced pervasive and prolonged Variscan tectono-metamorphic overprint and do not represent an older Precambrian ramp and (ii) that early Paleozoic Saxo-Thuringian marine lithologies were deposited on a vast contiguous Peri-Gondwana shelf. Incomplete recycling of extended continental crust during prolonged Gondwana Laurussia collision can explain the geological record of the Saxo-Thuringian Zone.

The Digermulen Peninsula in eastern Finnmark has attracted renewed research interest in recent years due to discoveries of new Ediacara-type fossils, marking the rise of macroscopic life on Earth. The entire upper Ediacaran and Cambrian sedimentary succession was considered to be siliciclastic. However, carbonates were discovered within the 2nd cycle of the Manndrapselva Member of the Stáhpogieddi Formation of the Vestertana Group (Meinhold et al., 2019, Precambrian Research, 328, 99-110). These carbonates occur as calcareous siliciclastic beds, lenses, and concretions, some with calcite spherulites and cone-in-cone calcite, in a mudrock to fine-grained sandstone succession approximately 40 m below the Ediacaran–Cambrian boundary. The calcite spherulites were probably formed at the sediment–water interface or a few centimetres below, either in a coastal littoral environment or in situ in the sublittoral zone under high alkaline conditions. In situ calcite U−Pb isotope data from an upper Ediacaran carbonate concretion provide timing constraints for depositional, diagenetic, and potentially metamorphic processes, overlapping and confirming previous estimates based on relative bracketing of events (Meinhold et al., 2020, Geological Magazine, 157, 1367-1372). The cone-in-cone calcite formed during burial diagenesis and clearly before low-grade metamorphism and cleavage formation, the latter being caused by the Scandian Orogeny.

The Lahn-Dill-Area, the Kellerwald and the Lindener Mark in the southeastern Rhenish Massif (Germany) are part of the Rhenohercynian Zone of the Central European Variscides. They contain various Devonian and Lower Carboniferous sandstones and greywackes, which differ significantly in their facies circumstances and fossil-content from surrounding autochthonous materials. U-Th-Pb- and Lu-Hf-analyses on detrital zircons of these allochthonous siliciclastic sediments indicate a provenance in the Saxothuringian zone and thus a Gondwanan hinterland. They show U-Pb-age clusters of ~530–700 Ma, ~1.8–2.2 Ga, ~2.5–2.7 Ga, and ~3.0–3.4 Ga. In contrast, samples from the autochthonous and par-autochthonous units of these areas show a provenance representative of Laurussia with debris primarily derived from Baltica and Avalonia with age clusters at ~400–450 Ma, 540–650 Ma, 1.0–1.2 Ga, ~1.4–1.5 Ga, ~1.7–2.2 Ga, and 2.3–2.9 Ga. These results, combined with own thin section analyses and geochemical data on volcanic rocks as well as revised biostratigraphy and paleobiogeography of Lower Devonian from the literature, led to the interpretation that the southeastern Rhenisch Massif is a nappe stack of Rhenohercynian and far transported Gondwana-related nappes. They were thrusted onto the autochthonous part of southern Laurussia during the Variscan orogeny by closing a wide Rheic Ocean.

High-grade metamorphic and plutonic rocks in crystalline complexes are of increasing interest as host rock for geothermal plays and for understanding plate tectonics. In this regard the Pretzsch-Prettin Crystalline Complex (PPCC, Saxony-Anhalt) as a part of the Mid German Crystalline Rise is one prominent example of a late-orogenic intrusion in the former Rheic Suture Zone. Former 2D geophysical investigations focussing on the setting and outline of the PPCC remained ambiguous and suggested a combined interpretation with other geoscientific disciplines.

Recently, we applied a 3D geophysical and geological modelling to the PPCC incorporating well data, seismic depth maps and gravity data. 3D gravity modelling revealed important information on the general geological setting of the overburden and basement depth, but did not allow detailed interpretation in areas of similar basement density. Limiting the generally ambiguous gravity modelling results required incorporation of petrographic data like rock composition from thin sections and density measurements at rock samples, which were linked to the modelled density zones of the basement.

This approach revealed first evidence of a northward extension of the comparable low density monzogranites to granodiorites of the PPCC into the North German Basin. Quartz monzonites and monzodiorites with up to 25 % biotite and amphibole agree with up to 0.15 g/cm³ higher basement densities in the surrounding of the PPCC. Generally, incorporating petrographic data into the gravity modelling process enabled us to better confine zones of different crystalline compositions, which might be applicable to other areas.

The Ouansimi copper mine is located south of the Kerdous inlier in the Western Anti-Atlas in Morocco. Neoproterozoic and Lower Cambrian sedimentary rocks record recurring transgressive and regression cycles by deposition of limestones, algae matts, or clastic rocks like conglomerates. The rocks are overprinted, likely due to the Variscan orogeny, resulting in an anticline formation showing internal large- and small-scale tectonic elements like folds, shearing, normal and reverse faults, as well as bend and drag folds.

The sedimentary rocks host mainly NW/SE striking veins with copper mineralisation, comprising e.g., chalcopyrite, chalcocite, sulfidic minerals, in combination with carbonates or quartz, as well as copper oxides (e.g., malachite) at the present-day surface. Processes, which lead to vein and ore formation and the possible tectonic influence are still not clearly understood. So far, the copper-bearing veins are mainly associated to the Variscan orogeny and hydrothermal influence. Field observations and structural measurements of stratigraphic bedding, fractures, and veins surrounding the Ouansimi mine are complemented with subsurface data, as well as transmitted and reflected light microscopy. Furthermore, microstructural observations are supplemented with cathodoluminescence microscopy.

This study will help to understand, if tectonic events beside the Variscan orogeny influenced the formation of veins and faults, as well as folds. Thus, the understanding of the regional geologic and tectonic processes of the Western Anti-Atlas region will be complemented.

The Late Paleozoic continental rift in the area of central Europe set the stage for intense magmatic activity, apparent in plutonic complexes (e.g. Brocken, Pretzsch-Prettin), large subvolcanic bodies (e.g. Halle laccoliths, Wurzen porphyries), and recorded by voluminous pyroclastic sheets in numerous caldera systems (e.g. Wurzen, Rochlitz, and Flechtingen ignimbrites). Since up to now, their petrogenetic evolution often remains veiled in mystery or is still under debate. Focussing on this post-Variscan magmatic flare-up, the obtained geochemical and mineralogical data set depicts selected magma reservoirs, their evolution, and storage.

The different compositions of the Cadomian to Variscan basement and the longevity of magma chambers set within these particular regions have a decisive influence on the geochemical characteristic. In detail, metasedimentary rocks (e.g. metamorphosed graywacke, mica schist) are most often directly responsible for Al₂O₃-supply and subsequently lead to corundum-normative magmas. The highest amount of normative corundum (up to 3.1 wt%) can be found in the Flechtingen ignimbrite, which magma system was capable of crystallizing almandine garnet (Ca_0.03Fe_0.84Mg_0.13)₃Al₂Si₃O₁₂) in lower crustal levels (>7 kbar ≙ 25 km). A similar picture emerges within the subordinated diopside-normative parts of the Wurzen volcanic rocks (up to 3.28 wt%), where crystallization of calcic clinopyroxene took place at 6 to 10 kbar (≙ 22 to 36 km). Here, it is proposed that parental diopside normative alkaline to tholeiitic and garnet-bearing magmas are fast ascending and mingled into upper crustal magma bodies.

The Elbe zone constitutes a complex fault zone on the northern edge of the Bohemian Massif. As part of this zone, the Elbtalschiefergebirge is juxtaposed with the Lausitz to the northeast and the Osterzgebirge to the southwest. The tectonic boundary with the Osterzgebirge is traditionally defined by the Mid-Saxon-Fault. In the course of a tunnel project for the railroad line Dresden-Prague structural geological investigations were carried out. Here first results are presented. The entire area was overprinted by the Variscan orogeny and can be divided into three principal units. (i) The northeastern section consists of very low-grade metamorphic lithologies representing the remnants of an early Carboniferous synorogenic basin. The adjoining unit (ii) is predominantly made up by phyllites that differs from unit (i) by its stronger tectonic and metamorphic overprint and partly inverted stratigraphy. Mylonites on both sides of the Mid-Saxon-Fault reveal the existence of a ductile shear zone (iii) affecting high- to medium-grade metamorphic units of the Osterzgebirge as well as low-grade units of the Elbtalschiefergebirge. This Elbe-zone parallel, i.e., NW-SE striking shear zone suite is characterized by dextral strike slip tectonics and the transition from ductile to brittle-ductile material behavior. The existence of ESE-WNW to E-W stretching lineations on both sides of the Mid-Saxon-Fault , however, indicates a more complex tectonic evolution. Furthermore, the mylonites adjacent to the “Tourmaline-granite” of the Elbtalschiefergebirge resemble the shear zone rocks of the Erzgebirge. Thus, the traditional view of the Mid-Saxon-Fault as a strict tectonic boundary between both units must be questioned.

The Holstein interglacial is classified as the period between the end of the Elster glaciation to the beginning of the Fuhne glaciation. The deposits in Brandenburg are supplied by limnic to fluviatile sedimentary regimes. Thus, the deposits consist of organic mud and silt as well as bituminous peat. Related to higher energetic levels, the fluvial associated deposits are made up of sand. The stratigraphic classification is based on palynostratigraphy and on the occurrence of the index fossil Viviparus diluvianus.

In this study, a new map is constructed that focuses on the distribution of limnetic sediments. Contrary to this, the existing maps summarise the limnetic and fluviatile deposits including the sediments of the lower Saale. Two sets of maps have been published since 1971 (Lithofazieskarte Quartär - scale 1:50 000 and Zwirner & Ziermann 2010 - scale 1:1 000 000).

Based on more than 400 palynostratigraphically proven locations (via drillings), a map will be published that achieves a significant extension and clarification of the distribution of the limnetic Holstein. The accumulation area of these deposits can be associated with numerous channel systems and paleo-basins initiated during the Elster glaciation. Furthermore, transgressive pathways are revised in this study. These were derived from Holstein Stage sea-level changes that resulted in transgressive and regressive successions with brackish to marine facies in northwest Brandenburg.

Zwirner & Ziermann 2010. „Verbreitung und Tiefenlage der Holstein-Warmzeit und frühsaalezeitlicher Ablagerungen“ in Stackebrandt, W. (Hrsg.). Atlas zur Geologie von Brandenburg. Landesamt für Bergbau, Geologie und Rohstoffe Brandenburg, 53.

New palynological and geochemical data from the KB Rehburg-2 core covering the German Wealden (W1-4) illustrate the unique development of this depositional setting. Despite the temporary isolation of the Lower Saxony Basin (LSB) from the open ocean, several marine flooding events into the basin were detected. Marine ingressions are suggested to have entered from the west via the East Netherlands High, supporting the existence of an - at least temporary - seaway to the Boreal Realm. In the central and eastern parts of the LSB, indicators of marine influence are less prominent. In this study, we use a combined approach including palynofacies analysis, sedimentological and geochemical data in order to improve the understanding of the highly variable German Wealden depositional environment. The new data provides evidence for marine ingressions into the isolated LSB, insights into vegetation dynamics and palaeoenvironmental conditions.

A total of five different types of palynofacies were distinguished, which indicate changes in the oxygenation state of the water column as well as variations in salinity. Based on changes in continent-derived particle abundance, the proximity to the Deister-Hils Delta can be estimated. The most proximal palynofacies type stems from palaeosols, which are described for the first time in the German Wealden. Marine ingressions were identified using ecological preferences of aquatic palynomorphs (dinoflagellates, acritarchs, prasinophytes, Botryococcus) across the studied sedimentary sequence. Based on changes in palynofacies and geochemical proxies, ingressions already postulated in other studies were identified and a new, previously unknown ingression is observed.

Here we present published and new age data of plutonic and volcanic rocks from Saxothuringia obtained by the high-precision CA-ID-TIMS U-Pb zircon dating method. This method has an uncertainty of ca. 0.1-0.2 % (corresponding to < ± 0.5 Ma) that is ca. 10 times smaller than all other recently established dating methods. Consequently, the application of this method allows better establish the exact sequence of magmatic processes in time and space. We show that magmatism in the Erzgebirge and in the Lausitz mainly occurred during two larger magmatic phases and that volcanic rocks first appeared in the Eastern Erzgebirge. We present also dating results from several volcano-sedimentary basins in Saxothuringia that allows a better comparison of their temporal evolution.

Near-surface geothermal energy as a key technology for the sustainable provision of heating and cooling is increasingly coming into focus as renewable energy and alternative to fossil fuels. In Saxony-Anhalt with an estimated 6,000 geothermal systems operational, several hundreds are being installed annually, incresasingly also in public and commercial buildings.

Areas, where water-soluble rocks carry the risk of karstification and sinkhole occurrence, are clustered in places of the Zechstein outcrop on the Harz Mountain rim, on the contours of the Halle Permo-Carboniferous complex and the Flechtinger Höhenzug. Near-surface Upper Buntsandstein, Middle Muschelkalk and Gipskeuper karstable rocks occur in the Weferlingen-Schönebecker Scholle, in the Hakel, Huy, Fallstein, the Oschersleben-Egelner salt axis, and in the Subherzyn.

Karst areas often contain particularly concrete-aggressive waters, so that special measures must be taken to protect geothermal probes. In addition, in the often cavernous or fissured rock, mud losses are to be expected, or the proper backfilling of the borehole is problematic. Further aspects can be the reduced thermal conductivity.

There is a risk of volume increase due to the transformation of anhydrite into gypsum after contact with water, which can lead to uplift of the terrain above evaporite lithologies. Building ground hazards can occur in the area of salt mining and near-surface salt deposits.

Permitting practice shows that for site-specific projects in the karst areas of Saxony-Anhalt sensu lato, heat recovery from the ground via geothermal collectors is recommended in order to avoid scoring, dissolution and hydration of the rock at risk of subrosion.

Das Geologische Landesamt Hamburg wird in diesem Jahr 75 Jahre alt. Die Tätigkeiten der Vorläuferinstitutionen reichen über 100 Jahre zurück. Die heutige Kernaufgabe des GLAHH ist nach GeolDG die Sammlung, Digitalisierung, Interpretation und Veröffentlichung von geowissenschaftlichen Daten. Inzwischen sind ca. 315.000 Bohrungen bis in eine Tiefe von mehr als 3.000 m digital erfasst und zum Großteil veröffentlicht. Das Bohrdatenportal des GLA-HH bietet zusätzlich zahlreiche Kartendarstellungen zu geologischen, geothermischen und hydrogeologischen Themenbereichen, z.B. die Geologische Karte 1:5.000, Präquartär-Karten, ca. 65 Profilschnitte bis in ca. 400 m Tiefe, Wärmleitfähigkeit und Temperaturen für verschiedene Teufenbereiche und hydrogeologische Profiltypen. Ein wichtiger, und von Dritten intensiv angefragter Arbeitsbereich des GLAHH ist die 3D-Modellierung. Während das tiefe 3D-Strukturmodell gemeinsam von den norddeutschen Ländern entwickelt wurde, wird in Hamburg ein „mitteltiefes Modell“ mit Schwerpunkt auf den wasserwirtschaftlich genutzten Bereichen von Quartären und Neogenen Einheiten bis in ca. 400 m Teufe dargestellt. Das dritte Hamburger Modell stellt das Quartär dar, differenziert in Grundwasserleiter und -nichtleiter, wobei bei letzteren Tills und Beckenablagerungen unterschieden werden. Auf Grundlage der gewonnen Erkenntnisse aus Landesaufnahme und der 3D-Strukturmodellierung werden auch wasserwirtschaftliche Grundwasserströmungsmodelle aufgebaut, um aktuelle Fragen der Trinkwasserversorgung im Ballungsraum Hamburg zu beantworten. Zukunftsthemen, wie eine erfolgreiche Umsetzung der Wärmewende mithilfe der oberflächennahen, mitteltiefen und tiefen Geothermie nehmen einen immer größer werdenden Raum ein und werden von den Bürgerinnen und Bürgern sowie von Unternehmen in Hamburg stark nachgefragt. Die Arbeiten zu Geogefahren umfassen die Themenbereiche Verkarstung (Erdfallbildung; Mikroseismik), Massenverlagerungen (Rutschungen am Elbhang) und Bauwerksschäden durch wasserempfindliche Böden (u.a. Sackungen über austrocknendem Lauenburger Ton).

Continuously growing demands for exploitation and storage in the near subsurface require up to date information on the setting of the unconsolidated Cenozoic rocks. Of special relevance are depth information on the base Quaternary for mapping Pleistocene tunnel valleys to answer hydrogeological questions and for preparing 3D subsurface models. Current studies in Saxony-Anhalt still incorporate the results of the map series “Lithofazieskarte Quartär” (LKQ), which was prepared between 1968 to 1984. However, newly available evidence from digitized seismic depth maps and drilling results suggest an update of the depth information of the base Quaternary in Saxony-Anhalt.

In a first step, wells penetrating the Quaternary were exported from the well database of Saxony-Anhalt and their stratigraphies were simplified. Relevant wells were subsequently selected by unambiguous stratigraphy, similarity of well elevation with DGM height, cross validation and comparison to the well database of the LKQ. The remaining 85.000 relevant wells were combined with newly stratified wells and digitized isobaths of the base Quaternary from seismic data and former studies to a new base map. Subsequent quality control comprised tests of different gridding algorithms and profile drawing.

The new depth map of the base Quaternary reveals updated pathways of Pleistocene tunnel valleys of up to 500 m thickness in the Altmark region and in Eastern Saxony-Anhalt. Here, changes to the LKQ are largest. Minor differences are observed in the western and southern parts of Saxony-Anhalt with thicknesses usually less than 50 m.

The publication and accessibility of geological data is one of the main tasks of geological surveys. Provided data helps to understand the local geology, facilitates exploration of natural resources and thus benefits state services, businesses, and the public alike. The State Geological Survey of Saxony-Anhalt (LAGB) uses its database from decades of geological exploration to provide information of the subsurface geology. Past interpretations existed but provided only simple presentations of the three-dimensional space. More recently, huge datasets were used for the development of largely enhanced 3D models. So far, regional 3D models have been prepared for the deep subsurface comprising the Altmark region in the north, the Subhercynian Basin in the middle, and the South-Eastern Harz Foreland in the south of Saxony-Anhalt. These models are based on existing maps from subsurface exploration, seismic profiles, and borehole information. ArcGIS and SKUA-GOCAD were used as data management and modelling tools. Some challenges consist of low data density in some regions, contradictory or incorrect source data, as well as in achieving a coherent 3D model by smooth integration of modelled layers from different authors. The resulting three-dimensional geological models of Saxony-Anhalt illustrate the structural setting and the geology of the Earth's subsurface and will become subsequently filled with further lithological and petrophysical parameters. To publish the models for a broader audience, we use the GST (Geosciences in Space and Time) framework. This toolkit eventually enables the creation of customized sections, virtual borehole profiles, and the export of parts of the models.

Geological mapping represents an important qualification within the framework of geoscientific programmes of study. The GeoMoDiM project, funded by Bonn University, aims to firmly integrate digitally supported geological mapping into the curriculum. In particular, the tablet- and cloud-based data collection in the field is to be prepared, carried out and evaluated with GIS support. This approach saves numerous work steps and avoids sources of error, allowing live communication and data exchange in the field.

This new procedure is already in practice, involving the students in the optimizing and streamlining process. Here we show that using tablets with QField the process of mapping can be improved through the ability of gathering all the data in one application compatible with the current workflow of QGIS, saving time and simplifying use. On top we integrate photogrammetry in the didactics, incorporating 3D models of outcrops into the subsequent analysis.

A second aim of this digital approach is to integrate students, who cannot participate in the fieldwork, into the process through video communication and live data exchange with partners in the field. Controlling of the fieldwork can be done online from a base station, evaluating, exchanging datasets and interpretative approaches with the participants in the field. Additionally, we focus on participants with disabilities, who are unable to join the field experience, they will benefit from this new didactic approach. The next step of this project is to open this new perspective to other research areas as botany and soil sciences.

Promoting quality education implies that teachers are reflective professionals, agents of innovation and change leaders, able to train students with critical thinking skills, problem-solving, creativity, collaborative work, and communication. In this conscious reflection, it becomes fundamental to shift the focus from teaching to learning, including the teacher himself, leading to developing new skills and attitudes, given the imperative of change. Thus, it is essential to establish teachers' continuous training relevant to initial training, which enhances their professional performance and, consequently, educational improvement. However, the pedagogical practices implemented in training must reflect congruent teaching with what is recommended as desirable in the professional version of future teachers, making the articulation between theory and practice a practical reality. In this action-research process, a pedagogical intervention programme was implemented in the course unit Didactics of Geology II of the master’s degree in biology and geology, according to an inquiry-based methodology focused on the active participation of the students and collaborative work among peers. With a holistic view of the Earth system for understanding the geological phenomena and processes, practical work was done. The laboratory and experimental geosciences activities were adapted from Orion’ previous work and contextualised according to the Portuguese Curriculum of the K7 grade. It was possible to collect evidence showing that pre-service teachers were encouraged to change their visions about how (geo)science can be learned and taught. Results reveal that the practical activities promoted (geo)science reasoning, meaningful learning, and professional development.

The concern with teaching centred on the characteristics and students’ needs is one of the reasons why the Multiple Intelligence (MI) theory is emerging and has become a trend in educational settings at the elementary, secondary, and higher education levels. Especial literature considers that intelligence is no longer restricted to cognitive talents but rather the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. These characteristics are based on eight types of intelligence Musical, Linguistic, Logical-Mathematical, Spatial, Bodily-Kinesthetic, Interpersonal, Intrapersonal and Naturalist intelligence. Exploring students' learning styles through their MI type allows teachers to identify their strengths and weaknesses and explore these styles in teaching methodologies. Additionally, teachers must understand students’ learning styles and MI to define activities that fit the different bits of intelligence by promoting better educational environment processes. In a pedagogical intervention program implemented in classes of the curricular unit of Didactics of Geology II (that integrates the curriculum of a master to train students to become biology and geology teachers), activities were carried out to teach and consolidate knowledge about Rock Cycle. After the intervention program, students presented the Rock Cycle in accordance with their style of learning. A content analysis was done on twenty-one “snapshot reports” done by the pre-service teachers. As in several studies that refer to the success of using the MI in the teaching process, our study gathered evidence of students' increased motivation to learn and a more active engagement.

The Science/Technology/Society perspective in promoting scientific literacy in metal recycling becomes fundamental for adopting good behaviours in our society that contribute to the independence of Europe on critical raw materials and, therefore, to the transition to greener technologies and circular economies. In this regard, researchers must develop recycling routes, manufacturers must design for recycling, and our society needs to become aware and educated about recycling and responsible consumerism. Teaching Natural Sciences to pupils from middle school is an opportunity to awaken and strengthen the student's curiosity about the world around them. Through an appealing and dynamic discussion exercise, the student’s learning process can be promoted by motivating them to understand the importance and impact of scientific problems, relating them to social issues and technological innovations in their daily life. The research reveals that storytelling is an enjoyable, meaningful, effective, and creative way to enhance teaching and promote learning. As a powerful education multidisciplinary strategy, storytelling should be promoted in Geoscience teaching, encouraging environmental sustainability behaviours and students' civic education. The created storytelling "Gil broke his mobile phone! Now what?" is a playful-sensorial animation for K7 students whose setting is a Natural Science class. Faced with the challenge “How can I contribute to sustainable development when my cell phone is no longer useful?” the plot appeals to students' awareness of behaviour change towards sustainable development. At the same time, it also addresses the issue of bullying in the school context.

Governmental and scientific institutions often have a problem communicating their data treasure to people outside their community. Presenting geospatial data in an appealing and accessible way is a challenge, especially when non-scientific people are the target audience. The app "UmweltNAVI Niedersachsen" sets out to do just that and demonstrates it using institutional environmental data. A person can discover the data in the immediate vicinity or in other locations. The data can be displayed either as polygons or as map layers (e.g. geotopes, noise and radiation pollution, flood areas, occurrence of wolf and lynx). When opening a dataset, the person receives various detailed information combined from different sources, like Wikipedia or Observation.org.
The app was designed for a broad user community of education, interested individuals or experts. Easy navigation, understandable operation and various functions that invite to discover are here to appeal to people of all ages. A knowledge area deepens the topics and allows dedicated viewing of individual datasets. Other functions, such as "geo-caching" of datasets, a quiz or the possibility to upload own photos to the data, are intended to motivate people to engage with the topics.
The project was initiated by the Lower Saxony Ministry for the Environment, Energy and Climate Protection/Germany and was implemented together with the companies Bearingpoint and wemove digital solutions. The principle of presenting geodata can also be applied to other areas. The software is basically available for subsequent use.
The poster shows essential aspects of the app and intends to arouse interest.
https://umwelt-navi.info/

GEOWiki@LMU is a constantly growing open platform for the promotion of practical and research-oriented knowledge acquisition. Its major objective is to provide information on methodologies relevant to geosciences, with focus on fieldwork, sample preparation and analytical methods. It offers students a quick overview including helpful practical tips and references to relevant literature. In addition, there are various new developments which are presented here:

OPEN-VHB: The GEOWiki@LMU team developed the course “Geosphere” on the platform of the “Virtuelle Hochschule Bayerns – VHB” to provide non-geoscientists an introduction into geoscience. Interactive tools are used to show how determination of minerals and rocks works, it also gives a short introduction in earth history or applied geology.

Moodle: This concept will be expanded to create a moodle based training-platform to provide interactive exercises not only for students but also for pupils and interested people.

The most fascinating aspect of GEOWiki@LMU is that it is elaborated by students of earth sciences. The contents are developed by students in courses or on their own initiative in interdisciplinary teams. The activity of the students is essential for the development of GEOWiki. It gives decisive impulses for the selection and structure of the topics, writing the articles and acquisition of funding. All topics are discussed in weekly editorial online-meetings and revised in close collaboration with lecturers and scientists. All graphics, icons and videos are created by the students. The website is also programmed by students, according to the motto: what doesn't fit is made to fit.

The annual Summer School on Vulcano, Sicily will take place at the end of June 2023. This poster gives an impression and an overview of the highlights of this successful field-activity based summer school. This two-week summer school, is being held for the 7th time, and provides an important training ground for students, scientists, researchers, and technicians by exposing them to a variety of disciplines from geology, volcanology, geophysics, astrobiology, to planetary sciences. This year's additional theme is going to be robotics and agriculture - how our advances in robotics, especially from the space sciences, can aid and support agriculture and food production. In addition to lectures, a number of scientific experiments are planned on Vulcano, such as geoelectrics, astrobiology, spectroscopy, robotics, and intelligent drone-based mapping for agriculture. The summer school participants get the opportunity to work in teams on the above topics and are involved in the data acquisition, processing, visualization, and presentation. Lunchtime lectures, evening social events such as poster sessions, astronomy, and GIS classes complement the field-based activities. The interaction and collaboration between researchers is encouraged to foster inter- and transdisciplinary learning and understanding.
In addition to institutional funding, the summer school would not have been possible without generous funding by the Helmholtz iFOODis project and EUROPLANET.

A pilot plant for an aquifer thermal energy storage (ATES) system in a contaminated aquifer is under construction at the scientific park of Leipzig. The research at this pilot plant is focused on developing and testing technologies to simultaneously store energy from shallow aquifers through an ATES system and remediate the contaminated aquifer.

For this purpose, investigations will be conducted in an approximately 10-meter-deep sandy/gravelly aquifer which is contaminated with chlorinated volatile organic compounds (Cl-VOCs). The main contaminants are trichloroethene (TCE, up to 6.0 mg/l) and cis-dichloroethene (cis-DCE, up to 0.4 mg/l).

With a two-well system that runs cyclically, the proposed ATES system will inject up to 80 °C heated water. This has a greater impact on the chemical composition of the groundwater than ATES systems that operate at lower temperatures. A previous field project revealed a considerable change in hydrogeochemistry and the microbiological community at temperatures of 45 °C and 60 °C.

As a result, this study investigates the hydrochemical and biological interactions that occur in the extraction and injection wells, the thermally affected aquifer as well as in the aboveground system. Cl-VOCs will be removed from groundwater using an on-site regenerable zeolite absorber (Fe-zeolite) and in situ degradation with persulphate.

Furthermore, these investigations will be supported by stable isotope biochemical and abiotic migration investigations of Cl-VOCs as well as microbiological and geochemical analyses including trace elements. It is anticipated to enhance the carbon footprint of urban energy management by the ATES operation, including groundwater remediation.

Within the KONATES project, an Aquifer Thermal Energy Storage (ATES) system is planned in the scientific park of Leipzig, where the groundwater is contaminated with chlorinated volatile organic compounds (Cl-VOCs). Supported by the SpeicherCity project, corresponding numerical model is being further developed and applied to study the environmental impact of ATES operation.

From the regulatory perspective, the operation of ATES system in the urban area should not induce temperature changes beyond a few degrees Celsius at the boundary of the properties. The challenge faced in the KONATES project is that this temperature limit will be quickly exceeded, as the injection temperature is planned to be ca. 80°C. This requires a careful planning on the timing, duration, and location of the injection, as well as the pumping rate.

To satisfy the regulatory requirements and facilitate the understanding of such impacts, a 3D numerical model has been constructed, simulating both hydraulic and heat transport process in the aquifer. The model is capable of predicting the propagation of the thermal plume in response to different design of injection temperature and flow rate. Due to the high groundwater velocity, it shows that at a pumping rate of 600 l/h, injection can only be carried out for 12 days continuously without increasing the groundwater temperature more than 2°C at the boundary.

The next step of model development is to include feature that reflects the elevated mobility of the Cl-VOCs, which is relevant to the quantification of extracted contamination in the surface treatment facility.

Aquifer Thermal Energy Storage (ATES) is a highly promising technology for storing excess energy due to its high storage capacity and small surface footprint. Despite its numerous advantages, planning, approval, and application are not yet widespread in Germany. Mineral precipitation and biofilm formation can lead to clogging of wells and aquifers. In addition, changes in the physico-chemical conditions may trigger the mobilization of toxic trace elements such as arsenic. The BMBF-funded joint project UnClog-ATES aims to investigate biogeochemical processes in the subsurface that may reduce the efficiency and long-term performance of ATES systems.

Sterile and non-sterile flow-through experiments are conducted under anoxic conditions, using both siliciclastic sediments and groundwater from a potentially ATES-suitable saline aquifer in Berlin. Through laboratory studies, the project investigates the effects of temperature changes, variations, and temporary oxygen input, and analyzes changes in the chemistry, mineralogy, and microbial community of both the groundwater and aquifer. Numerical models, including reactive transport and batch models, are developed using PHREEQC. Sensitivity analyses aid in the calibration and validation of models. They provide valuable insights into the geochemical behavior of the aquifer system and its response to different scenarios or conditions, by identifying the most influential parameters. Another key objective is to determine biogeochemical indicators that can be used to forecast clogging and define practical countermeasures to prevent or mitigate adverse effects in the aquifer.

Here we present our experimental setup and first modeling results for an ATES-suitable formation located in Berlin, Germany.

Microbial processes such as biofilm formation (clogging) and mineral precipitation (scaling) can affect the effectiveness of ATES systems. They can reduce the permeability of potential reservoirs and compromise the efficiency of ATES facilities on the long term. In addition, microbial processes can influence dynamics of toxic trace elements in the subsurface e.g. by releasing arsenic through iron mineral dissolution. Hence, it is crucial to identify microbial key players and metabolic processes to estimate the microbial impact on ATES and the clogging potential.

Here, we analyze the microbial abundance, community composition and their functional potential in relation to the thermo-hydrogeochemical conditions of bulk sediment and formation water of a Mesozoic sandstone aquifer of the North German Basin. The study focusses on the application of DNA-based approaches such as qPCR, high throughput sequencing and metagenomics. Bulk sediments and fluids were obtained from Jurassic sandstone in Berlin, Adlershof from a depth of 200-450 m.

The aquifer is characterized by an in-situ temperature of 17-22°C, Na and Cl dominated fluids (TDS ~20 g L^-1) and DOC including acetate (~3.5 mg L^-1), propionate and valerate. First results show that the fluid microbial community is adapted to saline and alkaline conditions. The community is highly dominated by the two taxa Alkaliflexus and Defluviitaleaceae UCG-011, but also contains sulfate reducing bacteria.

Results of this study together with a flow-through experiment analyzing geochemical, hydrochemical, mineralogical and microbiological processes under different conditions typical for ATES, will help to develop prediction tools for potential system operational failures and appropriate countermeasures.

The energy concept for the VW library in Berlin, which was built in 2004, centers on a ground foundation absorber (GFA) that uses concrete core temperature control to freely cool the building in the summer and cover the building's base heating load in the winter via a heat pump. Due to unexpectedly high subsurface temperatures beneath the building, as well as difficulties in controlling the concrete core temperature control system, the GFA has been largely decommissioned in recent years. The goal of this research is to work with building engineers and engineering geologists to determine the cause of the elevated temperatures and to transition the GFA to optimized seasonal operation. To this end, detailed thermal models were created for the building and the subsurface, validated with measured data, and coupling approaches between the models were investigated. This should ensure a better evaluation of the interaction between the subsurface and the building during operation. Model-based parameter studies will then be used to determine an optimally adjusted operation of the GFA. In addition, the temperature development of the subsurface of the study area will be investigated to ensure sustainable operation. Optimized reactivation of the GFA shows significant ecological and economic potential with annual savings of 15% of the building's CO₂ emissions and €23,000 in energy costs compared to the current building operation. The developed adjustments to the operating and control parameters will be tested and monitored in the building during the coming heating periods.

The University Campus Charlottenburg/Berlin will be used as an example to show how geothermal energy can make a decisive contribution to a climate-neutral university campus. In combination with heat pumps, geothermal energy offers the possibility of a secure heat supply for the campus, which is in the process of transformation. The investigation addresses the geological horizons Muschelkalk and Buntsandstein at depths of 900 - 1250 m. Temperatures of 45 - 63°C and an extraction capacity of 1.2 to 4.7 MW are expected. Depending on the outside temperatures, direct use for heat supply can take place. The ongoing renovation process on campus significantly increases the direct use potential of geothermal energy. In the retrofitted state, the maximum supply temperature drops to 60°C with an outside temperature of -10°C. This demonstrates that the geothermal use of the underground can provide a reliable heat source for the transformation process on campus or in city quarters in general. An essential aspect of this utilization is the redesign of the heating network to allow a differentiated supply of buildings with different temperature levels. The example of the location's south campus shows that the use of geothermal energy enables a CO₂ savings potential of up to 64%. In addition, the use of geothermal energy for cooling supply via ad- and absorption chillers is investigated. This approach opens up new perspectives for the holistic use of geothermal energy and helps to increase efficiency and conserve resources in campus operations.

While the share of renewable energy in the electricity sector is steadily increasing, it has stagnated in the heat supply, despite the fact that in Berlin, for example, more than 40 % of the CO2 emissions are caused by the heating sector. Due to its ability to store large volumes in the underground while at the same time taking up little space on the surface, HT-ATES is particularly well suited for use in urban areas and can therefore contribute to the reduction of CO2 emissions. However, clogging of aquifer pores thus reducing the permeability, corrosion and mobilization of trace elements may be undesirable effects of HT-ATES.
Here, the Triassic limestones and the Jurassic sandstones were investigated as part of two Berlin ATES studies with the aim of (a) simulating the effect of HT-ATES operation on the carbonate aquifer by geochemical modelling, (b) identifying reactive mineral phases by systematic elemental analysis using a handheld XRF and (c) estimating the permeability and mobilization processes by column and batch experiments at elevated temperatures.
The results show that rapid analysis of drill cores at the drilling site provides important information on the presence of reactive mineral phases such as iron minerals, clay and carbonate content, and can therefore assist in filter placement. The mobilization of organic matter and trace elements has been observed in laboratory tests with siliciclastic sediments. The simulation of the HT-ATES operation in the saline carbonate aquifer, on the other hand, indicated carbonate precipitation due to temperature increase and degassing.

Sustainable development of enhanced geothermal systems (EGS) requires a comprehensive understanding of the in-situ stress conditions. Among several techniques developed in the last decades, Hydraulic Testing of Pre-existing Fractures (HTPF) is a common practice to quantify the normal stress acting on hydraulically isolated fractures. To better understand the hydromechanical coupled mechanisms involved during HTPF as well as validation of HTPF analysis methods, a decimeter-scale true triaxial testing (TTT) apparatus was utilized that allows HTPF measurements on fracture planes under anisotropic stress conditions.

This work is primarily focusing on the experimental setup, calibration, and boundary conditions of the TTT apparatus. The apparatus contains three sets of oil-filled flat-jacks, which independently control the stress boundary conditions in the (horizontal) x, y, and (vertical) z directions. Contained within a steel frame, the flat-jacks exert pressures onto loading plates, which transfer and distribute pressure onto the sample’s surfaces. The 30*30*45cm cuboidal granite sample contains a vertical saw cut fracture, oriented 45° in respect to the x and y axis. Boreholes, drilled through the sample to the fracture surface, allow high-pressure fluid injection and monitoring of the fracture fluid pressure. Thirty-two acoustic emission sensors, mounted in the loading plates, allow for active and passive seismic measurement. The deformation of the rock sample is captured by 16 linear variable differential transformer (LVDT) displacement sensors mounted externally to the loading plates. The test procedure and preliminary results of the HTPF tests can be found in Osten et al. (2023; this conference).

The deep geothermal reservoir potential in North Rhine-Westphalia was assessed in Devonian carbonates (Massenkalk) in the Steltenberg Quarry in Western Germany. The karstification phenomena of the carbonates were recorded utilising drone images in the quarry. Rocks at the karst chutes were examined by polarisation- and cathodoluminescence microscopy regarding karstification phenomena and carbonate cements. X-ray diffraction and inductively coupled plasma analyses were carried out to gain mineralogical information about different carbonate phases in various samples. Carbon and oxygen isotopes were analysed to understand the formation conditions of the carbonates. The examined rocks at the karstification structures show that the host rock (Massenkalk) has average marine δ¹³C_mean values of 3.7 ‰ VPDB and -4.7 ‰ VPDB for δ¹⁸O_mean. At the karstification surfaces and leaching zones, the isotope analyses revealed values of meteoric overprinting in the form of increasingly more negative δ¹³C values down to -8.5 ‰ VPDB and -5.9 ‰ VPDB for δ¹⁸O. These changes in the formation conditions are strengthened by cathodoluminescence results. The narrowing of karstification observed by drone with increasing depth in the quarry walls and the siliciclastic sediments in these structures indicate near-surface karstification. These dissolution structures have presumably developed in cracks caused by tectonism. It can be assumed that karstification at greater depths is also possible due to fault associations, which could be caused not only by meteoric waters but deep hydrothermal CO2-bearing fluids

Deep geothermal power plants are baseload-capable and can serve as substitutes for fossil fuel power plants. In the Ruhr region of Germany, a densely populated area with high energy demand, potential deep geothermal reservoirs have been limited to a few sedimentary layers, specifically Carboniferous and Devonian strata. These reservoirs have not been explored with hydraulic field studies for geothermal purposes so far. Deep boreholes for geothermal research are non-existent, so shallow boreholes provide an analogue for evaluating the potential of deep reservoirs.

For this study, a naturally-fractured Carboniferous sandstone and a karstic dolomitic limestone reservoir of the Devonian were investigated using geophysical borehole measurements, hydraulic and hydrochemical experiments, and acoustic/optical televiewer recordings.

The sandstone formation (investigated depth: 20 – 305 m) showed a low hydraulic conductivity, and it is probably necessary to drill into fault zones or to enhance the permeability via stimulation in future geothermal projects. Chemical enhancement of permeability was attempted using CO₂ to dissolve carbonate fillings in fractures, but further research is needed to evaluate the effectiveness of this method.

The dolomitic limestone formation (investigated depth: 10 – 224 m) exhibits exceptional permeability due to enlarged fractures, cavities and vuggy porosity resulting from karstic processes, making it a promising reservoir overall. However, further confirmation is required at reservoir depths (e.g. 2500 – 4000 m).

In summary, deeper geothermal reservoirs in the Ruhr region have not been explored enough so far, and further field studies are necessary to evaluate their potential for geothermal energy production.

Groundwater temperatures (GWTs) vary based on the local geothermal heat flux, the energy budget at the surface, and land cover. With subsurface temperature data being scarce, standard techniques for the spatial interpolation often produce unrealistic representation of shallow GWT. It has been shown that utilizing remote sensing data can reproduce shallow GWT at an error of roughly 1 K. In our contribution, we apply such a technique to the state of Saxony-Anhalt, Germany. The estimation is trained and validated with a set of over 600 observation wells. The data used comprises data from the Landesbetrieb für Hochwasserschutz und Wasserwirtschaft Sachsen-Anhalt (LHW) as well as own monitoring campaigns for the cities of Magdeburg, Halle (Saale), and Dessau. Together with different satellite datasets, such as land surface temperature and building density, we use this measured GWT data to derive spatially resolved estimated GWTs (eGWT) for Saxony-Anhalt. The measured and estimated GWTs are then correlated to the land cover at the location. Thus, this study aims to (1) present measured GWT and eGWT distribution for Saxony-Anhalt, (2) assess the application of satellite data for estimating shallow GWT, and (3) research the correlation between GWT/eGWT and land cover.

To extract heat from tight deep subsurface formations, hydraulic stimulation is used to create efficient heat exchangers in the context of enhanced geothermal systems (EGS). Successful geothermal reservoir initiation requires detailed characterization of the regional in-situ stress field and local stress field variations of heterogeneous, i.e. fractured and faulted rock masses, which is often achieved by hydraulic fracturing (HT) and hydraulic testing of pre-existing fractures (HTPF).

To further develop and validate these field-scale in-situ stress determination techniques, decimeter laboratory scale HTPF tests into saw-cut and polished fracture planes are performed in a true triaxial testing apparatus (see Cadmus et al. 2023, this conference for details). Tests are carried out under various anisotropic stress boundary conditions to analyze normal opening and shear behavior. Results of two rock samples with different fracture roughness are analyzed and compared in terms of the injection pressure and flow rate evolution, shear displacement and acoustic emissions. The results indicate that both shear displacement and hydraulic jacking initiate as the injection pressure exceeds the fracture normal stress, which is attributed to heterogeneous fluid pressure distribution in the fracture plane. Future experiments on a fracture surface of intermediate roughness with additional observation boreholes aim to further assess the effects of fluid pressure distribution and fracture plane roughness in the context of stress measurement and induced seismicity.

Hydrothermal systems offer significant potential for green energy and heat production. The Buntsandstein Formations provide aquifers that are applicable for hydrothermal heat (or power) production. The Geological Survey of Brandenburg (LBGR) will improve its data base on Middle Buntsandstein aquifers using machine learning algorithms on archived exploration data.

Data stored in the archive of the LBGR contains drilling information for some 200 boreholes penetrating the Buntsandstein Subgroup. The LBGR has access to some thousand 2D seismic profiles from exploration surveys, typically reaching the Zechstein Group or the deeper-lying sandstone aquifers in the Upper Rotliegend Subgroups.

Drilling logs such as gamma ray or density logs provide valuable information for stratification and petrophysical rock property analysis. Available drilling logs will be digitized, and machine learning algorithms will be trained on exemplary data sets such as drilling E Hr 1/68. Machine learning algorithms will help to stratify the Buntsandstein sections of the available drillings. The stratification based on machine learning is further validated on newly interpreted seismic and drilling results, such as the cores stored at the drilling core and sample archive of the LBGR. The base will be in consideration of depositional gaps and tectonics. Also, a well-to-seismic-tie is performed at selected locations, and synthetic seismic profiles are generated.

If possible, seismic lines are (semi-)automatically evaluated to identify Hardegsen, Detfurth, and Volpriehausen Formations. Interpretation results are integrated in a 3D-geological model to build a regional-scaled Buntsandstein model of Brandenburg, allowing parameterization and calculation of reservoir temperature or heat in place.

The subsurface of the Aachen-Weisweiler area with its Carboniferous and Devonian carbonates is a green-field target location for testing and developing deep geothermal energy systems in North Rhine-Westphalia, Germany. Despite subsurface mining, surface mapping and isolated deep exploration wells and crustal seismic data, only sparse information on the deeper structures (down to 4,000 m), the spatial distribution of the reservoirs and reservoir properties has so far been recorded and/or published. Therefore, the complex structures of the faulted and folded Paleozoic layers remain unknown requiring further investigations. With the “Field Scale Laboratory for Deep Geothermal Energy Rhineland”, we aim to characterize the subsurface of the Aachen-Weisweiler area including its structural uncertainties, to quantify the reservoir properties of the carbonates and their associated parametric uncertainties to better describe the geological risk in exploring the reservoirs. Firstly, we constrain a geological model based on the publicly available surface and subsurface data and quantify its structural uncertainties. The model and the uncertainties are revised after the integration of vintage and newly acquired seismic data. Planned deep exploration wells will provide further constraints for the structural model but also deliver in-situ measurements of reservoir properties and geomechanical properties for subsequent thermo-hydraulic-mechanical modeling. The investigations contribute to the characterization of the potential geothermal reservoirs in this region, aid in the exploitation of the reservoirs, finding drilling locations for wells, and expand geological knowledge of the carbonates from other regions into Germany, hence, de-risking the geothermal plays in the Aachen-Weisweiler area.

The Opalinus Clay is the chosen host rock for the Swiss deep geological disposal of nuclear waste, and it is also investigated in Germany. For the long-term integrity of the disposal site, temporal and spatial stable geochemical conditions are essential. The identification of mineralogical and geochemical alterations in the Opalinus Clay and surrounding formations gives insights on their stability in the past, and thus enables an assessment for the future.

To detect the mobility of chemical elements and associated mineralogical changes, a 58 m long borehole was drilled at the Mont Terri Rock Laboratory (Switzerland). Drilling was conducted from the Opalinus Clay through the entire underlying Staffelegg Formation, which includes two water-bearing sections. The rock members and their transitions were characterised with a variety of analytical methods.

The results show that many trace elements are particularly enriched at the upper transitions of the water-bearing sections. At the top of the Rietheim Member (Posidonia Shale), this enrichment is accompanied by an increase in pyrite, which can be interpreted differently. On the one hand, the depositional conditions may have led to enhanced pyrite formation and the associated pyritization of trace metals. On the other hand, the overlying rock layers could have acted as cap rock for mobile elements in the pore water, leading to the observed accumulations. Consequently, to distinguish between depositional or diagenetic and alteration or mobilisation features is crucial for the interpretation of the analytical results in order to assess the long-term stability of Opalinus Clay and surrounding formations.

Geothermal systems in crystalline basement rocks require fractures and faults to allow economic heat production. Sufficient permeability of these flow paths is vital and affects the lifetime of such systems. As fluids are produced and reinjected, the resulting flow, fluid mixing as well as related pressure and temperature changes affect the geochemical equilibria between fluids and host rock. Disequilibria of fluids and rock then potentially drive geochemical alteration (e.g., dissolution, precipitation, illitisation). Such changes can affect the hydraulic properties of the major flow paths of the fault zones. Cornwall in SW England hosts several granitic plutons that are subject of current geothermal projects (United Downs Deep Geothermal Power and Eden Projects). These projects target fault zones in crystalline rock as pathways for fluid flow.

To study the effects of geochemical alterations on fracture permeability in granites, we conducted a series of long-term reactive transport experiments in our unique flow-through reactor setup. Carnmenellis granite samples from central Cornwall have been collected of which small, artificially fractured plugs (15 mm length, 10 mm width) and powders (< 125 μm grain size) were prepared. We injected water with different fluid composition, representing brines encountered around geothermal systems, into the fractured granite plugs and pulverized gouges at 80 °C and 20 MPa confining pressure. The development of sample permeability and effluent composition are analysed. CT-scans are used to analyse changes in fracture and gouge structure. To complement the experiments, we model our system with GeoChemFoam [Maes and Menke, 2021], an OpenFOAM-based reactive-transport modelling code.

Migration of neptunium, i.e. ²³⁷Np, a minor component of high-level nuclear waste, is in focus regarding the safety of nuclear waste disposal sites due to its long half-life and radiotoxicity. Opalinus Clay, the preferred host rock in Switzerland and also an option in Germany, is regarded as a reference formation with diffusion as the dominant transport process additionally retarded by sorption. One-dimensional diffusion simulations are conducted with PHREEQC to quantify neptunium migration. Sorption on clay minerals is integrated using surface complexation models. Numerical simulations are based on two diffusion experiments with the same setup, but one order of magnitude difference in transport parameters attributed to the core samples which stem from different rock facies. In the laboratory experiments, Np(V) was applied via a synthetic oxygen free pore water with neutral pH. The redox conditions are controlled by pyrite, while the pH of the system is buffered by calcite. The experiment of Fröhlich et al. (Radiochimca Acta, 2013, 101, 553-560) defined the numerical setup applied to the experiment of Wu et al. (Environmental Science & Technology, 2009, 43, 6567-6571). Our results indicate that neptunium migration is mainly controlled by pyrite oxidation and the associated reduction of Np(V) to Np(IV), while clay mineral quantities have only a minor impact. Since neptunium speciation and hence migration is very sensitive to oxidation and reduction reactions, redox conditions need to be accurately controlled and monitored in the laboratory if transport parameters are determined to be applied in the context of safety assessments.

The poster presents the framework of the modeling part of the BMWi-funded project "Li-Fluids" (grant number: 03EE4034A). It introduces PHREEQC modeling approaches for simulating lithium-bearing minerals in geothermal reservoirs. By integrating lithium sources into PHREEQC, the release of lithium can be simulated. Additionally, a 1D dual-porosity approach is used to define reservoirs and calculate time-dependent depletion.

However, there are challenges. The accurate calculation of brines requires the Pitzer approach, which is limited in the number of minerals considered and does not include aluminum. Li-Mica, a modified form of K-Mica, appears to be an important primary source of lithium in the host rock. To address these limitations, other databases like the SIT database can be extended to include lithium-bearing aluminum silicates.

Saturation experiments were conducted up to 200°C using pure H₂O, approximating the observed Li⁺ concentrations from gold capsule experiments conducted by the project partner BGR. These concentrations ranged from a few mg/l Li⁺. Since Al³⁺ is necessary for calculating the saturation indices of Li⁺-bearing aluminum silicates, the use of pure H₂O was necessary to combine the BGR's laboratory experiments with PHREEQC's capabilities.

The next step involves implementing reservoir properties and developing an approach for modeling transport using concentrated saline waters frequently encountered in deep sedimentary basins in Germany. Van Genuchten's (1985) approach, which incorporates dual porosity similar to sedimentary rocks, will be utilized in PHREEQC. This hydraulic extension, combined with deep saline waters (e.g., the North German Basin), facilitates the extrapolation of findings from pure water experiments to a quasi-reservoir.

In the context of the energy and mobility transition, operators of geothermal power plants and associated industries spotlight the potential to combine the production of sustainable energy with the extraction of strategic raw materials (SRM) (e.g., lithium) from geothermal fluids. Brine mining of SRM requires a comprehensive understanding of the related geothermal fluid system.

In southwest Germany, the Upper Rhine Graben (URG) represents a reservoir with great geothermal and SRM potential (thermal gradient up to 120°C/km; Li ~170mg/L). Data about the reservoir rocks and the thermal fluid at different depths is provided by ~1300 oil and geothermal wells as well as thermal water wells. Chemical data of sampled fluids indicate variations in the trace element distribution that are related to the Cl/Br-ratio, and trends of stable isotope systematics of the water.

The results show that in the northern URG evaporites are dissolved (Cl/Br>1200), while in the central URG the thermal waters have almost seawater composition (Cl/Br=290). Independent of the Cl/Br ratio, Li concentrations in the thermal waters vary between 3-43 mg/L. At nearly the same Cl/Br ratio of ~300 the geothermal fluids have ~170 mg/L Li. Stable isotope systematics imply that all thermal fluids have a meteoric component. The results indicate a modification of the fluid chemistry through time and depth, resulting from fluid mixing and water-rock interaction with various reservoir rocks. To investigate the fluid evolution, additional element tracers to determine the origin and raw material potential of Li and other trace elements, are established.

Petalite was the first mineral in which lithium was detected, but its economic importance is less than that of the lithium-rich spodumene. Both minerals occur in pegmatitic deposits (LCT pegmatites), which were explored in the past mainly for tin and tantalum. Nowadays, lithium-bearing minerals are the focus of mining. Although both minerals are similar in the processing and extraction of lithium, their mineralogical properties differ. Through roasting, petalite undergoes a phase transformation to β-spodumene, producing quartz as an excess. Subsequently, the roasted material can be fed into the established converter process to produce lithium hydroxide or lithium carbonate.

In order to cover the increasing demand for lithium for use in lithium-ion batteries as a contribution to the energy transition and the associated turn away from fossil fuels, investments in mining projects away from the particularly lucrative spodumene pegmatites are necessary. Petalite is one such alternative.

Using petalite deposits in Namibia as an example, we will show whether it is possible to determine the mine of origin based on mineralogical and geochemical properties to contribute to possible lithium fingerprinting as proof of origin. The approach is based on the combination of different analytical methods, such as EDX, electron microprobe and trace element distribution using ICP-MS. Lithium fingerprinting can then be used as a tool for material-based control of ESG criteria upstream in the lithium value chain.

Lithium is a critical raw material for the EU, being strategic for the energy transition, especially for battery production. Solutions are needed to reduce the EU dependency on the whole value chain and the geopolitical risks associated with the growing Li demand in a concentrated market. The deep geothermal reservoir in the Upper Rhine Graben (URG) along the German-French border not only show good conditions for direct energetic use but also high Li contents (160-200 mg/L). In this context, the deep geothermal reservoir has generally very similar geothermal and hydrochemical characteristics. An innovative lithium extraction process developed on Argentine brines by ERAMET and IFPEN was therefore installed directly on an extraction unit at the reinjection branch of an existing geothermal plant in the ORG. In the course of pilot-scale tests, the possibility of extracting lithium from geothermal brine was demonstrated in early 2021 in collaboration with Electricité de Strasbourg in the frame of the EUGELI project.
The extent to which lithium extraction can maximize the utilization of geothermal resources by combining lithium extraction with electricity and/or heat production via a single well will be shown in this poster presentation at an economic sensitivity assessment by evaluating the various key parameters and then subjecting them to a specific variation. Ultimately, this combined use of geothermal resources at an existing facility will demonstrate the extent to which environmental and social impacts can be avoided compared to conventional mining, or conventional brine lithium production.

The Hils Syncline is located in the south of the Lower Saxony Basin, Lower Cretaceous and Jurassic rocks crop out in its center. The Cretaceous and Jurassic sedimentary sequences in northern and southern Germany are known to be largely composed of clay-rich shales suitable for nuclear waste storage. Highly variable thermal maturity increasing towards the northwest characterizes the Hils Syncline, which makes it a natural laboratory to study the effects of burial and thermal maturation on petrophysical properties of shales at different levels of thermal maturation, which is our focus.

We reconstructed the burial and thermal history of the Hils Syncline resulting from a 3D-thermally-calibrated numerical model to better understand its geodynamic evolution, constrain maximum paleo-depths, –temperatures and erosion amounts, and evaluate their influence on the present-day petrophysical properties of Cretaceous and Jurassic units.

The basin experienced continuous subsidence interrupted by the Upper Cretaceous major phase of erosion. During the latest Early Cretaceous, deepest burial and maximum temperatures of Jurassic and Cretaceous rocks occurred showing an increasing northward trend. These units' porosity and vertical permeability decreased while the vertical thermal conductivity increased during burial. The Late Cretaceous inversion caused severe uplift and erosion that was stronger towards the northwest where up to 3,200 m of sediment was eroded compared to only about 1,200 m in the south. The petrophysical properties were not affected by the inversion according to the model. Calibration is currently performed based on new cores of Pliensbachian shales; thus, model results and experimental data will be compared.

In the context of the site selection procedure for a high-level radioactive waste repository in Germany, the fluid content in salt rocks is an important parameter to evaluate their barrier properties (i.e. gas formation potential and fluid pathways). Moreover, it can affect hydraulic conductivity, heat resistance, rock mechanical properties and it can be used for the spatial characterisation of the host rock. Fluids in rock salt (halite) are typically present in small, unconnected inclusions located within crystals or arranged along crystal boundaries and fissures, and can consist of brine, minor amounts of gases and hydrocarbons. When estimating the fluid content of rock salt, the main challenges are the low fluid content, the low permeability of the bulk rock preventing fluid extraction and the spatial heterogeneous fluid distribution. In summary, the measurements are time intensive and the results are highly dependent on the sample selection and preparation.

Nuclear magnetic relaxation (NMR) relaxometry is an established petrophysical method for a non-invasive characterisation of hydrocarbon host rocks and its fluids but it has not been used for rock salt so far. We present first results obtained from steeply inclined Zechstein rock salt (z2HS2) and compare them with a water content estimated by an extensive grinding of the salt samples in dried acetone and a subsequent analysis of the extracted fluids using infrared-spectroscopy. First results show, that NMR has promising features including a low limit of detection, non-destructive and quick measurements, no need for extensive sample preparations, and averaging over a large sample volume.

This study investigates sealing properties of Jurassic claystones, specifically Lias and Dogger mudstones of the Lower Saxony Basin, in the context of the disposal of high-level radioactive waste. Within the repository, the occurrence of various mechanisms such as corrosion, radiolysis, and microbial degradation may lead to generation of gases including hydrogen, methane and carbon dioxide. It has been reported through experimental studies that claystones possess hydraulic conductivities ranging from 10^-12 to 10^-15 m/s, indicating that the primary mechanism to dissipate the generated gases away from the repository is diffusive transport. Excessively high diffusion coefficients may compromise seal integrity, while overly low diffusion coefficients could result in localized overpressure zones, free gas formation, and interconnected gas transport pathways. Therefore, it is imperative to conduct a comprehensive investigation of gas diffusion in the context of nuclear waste disposal.

In the present study we assess the use of the pressure decay technique to measure gas diffusivity through water-saturated claystones. The experimental approach involved conducting radial gas diffusion into the pore space of core plugs that were sealed at both ends. Gas diffusivity was determined using a mathematical model that couples the analytical solution of the diffusion equation with the real gas law. Experiments were conducted on deionized water and water-saturated Boom Clay to determine hydrogen and methane diffusion coefficients, and the results are highly consistent with literature data obtained from other techniques. Currently, the measurement of hydrogen, carbon dioxide, and methane diffusion coefficients through water-saturated Lias and Dogger rock specimens is underway.

Middle Jurassic Opalinus Clay (OPA) is considered as host rock for the disposal of heat-generating high-level radioactive waste. For the present study, samples from the Mont Terri rock laboratory (Switzerland) were analyzed using sedimentological, mineralogical and geochemical methods. Thereby, the ordering of irregular illite-smectite interstratified clay minerals (I-S) was of particular interest as it is responsible for sorption of radionuclides and swelling properties.

Results support the classification of OPA into five main facies instead of the well-established threefold division, and further into six subfacies. The clay fraction present in the samples varies according to these facies, consistent with variations in cation exchange capacity. X-ray diffraction analyses of this < 2 µm fraction revealed a homogenous composition of the main constituents, namely R1-ordered I-S, illite and kaolinite. Crystal-structure based Rietveld refinement indicates strong similarities in the nature of disorder of the interstratified illite-smectite minerals. In all facies and subfacies the amount of illitic layers in the I-S varies from 73 - 85 % for all refinements and ordering types. Collectively, results point to (1) a homogenous overprint of the clay assemblage during burial and/or (2) a uniform siliciclastic sedimentary supply throughout the sedimentation period of the OPA.

This uniformity will facilitate the calibration of mineralogical models and the extrapolation of geophysical logging data where no data is available. However, the transferability of these calibrations to both other OPA locations and claystone formations should be critically examined.

According to the ‘Repository Site Selection Act’ (Standortauswahlgesetz – StandAG), the German site selection procedure is an iterative process and consists of three phases with increasing levels of detail in which the assessed area is continuously reduced during the process. Starting with an empty, so-called ‘white map of Germany’, BGE (implementer of the German site selection procedure) completed Step 1 of Phase I in September 2020 with the submission of the Sub-areas Interim Report (BGE 2020). In the report, BGE identified 90 individual sub-areas (in claystone, rock salt and crystalline rock), where favourable geological conditions for the safe disposal of high-level radioactive waste can be expected.

In Step 2 of Phase I, BGE aims to localise siting regions within the 90 sub-areas by applying preliminary safety assessments and other scientific criteria. Within the preliminary safety assessments, subsurface data are interpreted and the results documented. The workflow comprises the detailed characterisation and interpretation with focus on the host rock formation that acts as the main geological barrier, but also considers the surrounding rock formations.

This contribution describes some of the compulsory geoscientific interpretation steps (e.g. well log interpretation, subsurface modelling) that are required during the preliminary safety assessments, focusing on sub-areas with flat bedded rock salt. The assessment of the spatial geometry of potential barrier rocks as well as the interpretation of their internal configuration (e.g. facies) and the understanding of relevant geological processes affecting the safety of a potential repository site are important characteristics.

Rock salt is one of the three potential host rocks for the final repository for high-level radioactive waste in Germany. For the site selection procedure and for safety assessments, the content and composition of trapped fluids can be crucial to evaluate the potential of gas formation. Certain salt formations in northern Germany are known to contain gases and hydrocarbons as fluid inclusions. Fluid inclusion studies can provide information on their composition or temperature- and pressure conditions of fluid migration. Investigating individual fluid inclusion assemblages has certain advantages compared to bulk analyses: (1) the possibility to differentiate between different fluid sources and/or (2) the reconstruction of a complex fluid history. Among the suitable methods for the analyses of the fluid inclusion composition is Raman spectroscopy. Here we used a Renishaw inVia QONTOR Raman spectrometer attached to a Leica microscope (DM3000) equipped with a 100x objective and a 532 nm laser. Raman spectra were obtained with a 2400 grating, at ~5 mW, 180–240 s acquisition time and 2 accumulations in the spectral range of 300–4000 cm^-1. The analyses of the hydrocarbon phase show peaks at ~940, at 2500–2700 and 2900–3100 cm^-1 indicating C-H stretching modes, potentially of alkanes and their derivatives (Dollish et al., 1974; Orange et al. 1996).

The selection procedure to identify the site “best possible” to host Germany’s repository for the final disposal of its high activity nuclear waste considers claystone, rock salt and crystalline rock as potential host rocks. Preliminary considerations estimate the area required for a claystone-hosted repository to be 10 km². There are nine “sub-areas” (i. e. areas with conditions expected to be favourable for the safe final disposal of high activity nuclear waste) having claystone formations as potential host rock. Their sizes range between 943 and 62,885 km², which is roughly 90 to 6000 times the size considered necessary for a claystone-hosted repository. Consequently, reducing sub-area size sophisticatedly constitutes a major challenge to the site selection procedure.

The project SEPIA aims to apply a sequence stratigraphic approach to characterize and correlate barrier properties of Aalenian rock formations, namely the Opalinus Clay (OPA), in Southern Germany. Therefore, four drillcores constituting an approx. 330 km long transect have been acquired to derive the spatial distribution of clay-rich and -poor horizons across the sedimentary basin, eventually leading to a paleofacies map. In addition, correlation with results from similar investigations in Switzerland adds another 100 km to the transect. This will allow assessing to which degree results from the OPA characterization carried out in the Swiss site selection procedure can be transferred to Southern Germany. Overall, the approach used in SEPIA appears to be a promising one to identify potential siting regions of reasonable size out of the large sub-areas for detailed exploration.

The characterization of potential host rocks for the final disposal of high-level radioactive waste is of great importance in the site selection procedure. For clay-rich host rocks, hydraulic and geomechanical characteristics often depend on the burial history determining the maximum effective stress and temperature (i.e., maturity), and the associated compaction as well as transformations during diagenesis. Therefore, the direct transferability of host rock properties between different regional-geological sites is challenging and requires detailed quantitative knowledge about host rock property variations at different maturity levels.

We present the first results of the “Maturity” research project that deals with a Lower Jurassic clay rock via field and laboratory investigations. The target formation of Pliensbachian age (182–190 Ma) is located in the Lower Saxony Hils Syncline and the neighboring Sack Syncline. Whereas the mineralogical composition can be considered similar, the clay rock is characterized by a large thermal maturation gradient over a relatively short lateral distance. The project involves shallow core drillings at five locations along the sequence of changing maturities and an extensive testing program. We explore the influence of thermal maturity on the i) hydraulic rock mass properties using in-situ single-hole and cross-hole hydraulic tests within fixed packer intervals, and ii) petrophysical and hydromechanical properties by conducting a variety of laboratory tests on core material. In this contribution, we present preliminary results of our field and lab testing campaigns including thermal maturity-dependent hydraulic rock mass and geochemical characteristics as well as porosity and mechanical strength determinations of the clay rock.

The numerical modelling of the in-situ stress state is commonly performed for reservoir management or subsurface applications such as nuclear waste repositories. Modelling is required due to the sparsity of available stress magnitude data records in addition to the uncertain underground structures and heterogeneous material properties. Even though, geomechanical models provide an increase in confidence and allow an interpretation of the in-situ stress state, the associated uncertainties are very high.

We present an approach where, instead of just one model scenario that is a best fit to all available data (but necessarily has a poor fit to some data records), a wide range of model scenarios that each satisfies at least one data record perfectly is estimated. Then, additional indirect data on the stress state or other manifestations are added in order to assess the predictive quality of each model scenario. These can be for example Formation Integrity Tests or Borehole Breakouts. While model scenarios that have a good agreement with indirect data are preferred, those that are largely in contradiction are neglected.

Eventually, this approach can be used to increase the knowledge on the subsurface. Of all things, remaining contradictions help to identify anomalies or geographical and lithological areas where the model is not representative (yet). This allows to improve and evolve the model in a data-based way not only based on geomechanics. Thus, adding uncertainties and further indirect data to the standard toolbox empowers the significance of a model.

The NdFeB magnet world demand has doubled since 2005 to reach above 120 kton in 2020 [1]. The growing demand for REEs prompts their recycling. Sintered NdFeB permanent magnets are usually composed of above 20 wt.% Nd and a few wt.% of Pr and Dy. There are two main recycling ways for REE-based magnets. In the “short-loop process”, the main alloy is maintained in the valorized magnets, meaning that the microstructure and magnetic properties directly arise from the end-of-life product. In the “long loop” recycling process, one tries to extract the REEs from the alloy, which is the purpose of the present work.

The chemical separation of REEs from each other is difficult due to the similarity of their chemical properties. Following the encouraging results obtained by [2] in recovering REEs from NdFeB by hydrothermal treatment, we developed a geochemical approach of aqueous fluid – REE-compounds interactions based on the use PHREEQC software with the implementation of relevant REE-phases in the database. The database is tested against hydrothermal experiments on NdFeB powders with in-situ solution sampling. When reacted at 250°C and 100 bar, NdFeB powders transform into Nd(OH)₂, magnetite and Nd-borates along with large amounts of H₂. The low Nd solubility measured in the experiment is likely controlled by Nd-borates. The database will allow to investigate the effect of chlorine or CO₂ on the REE behaviour.

[1] Yang, Y. et al. (2017). J. Sustain. Metall., 3, 122-149.

[2] Maât, N. et al. ACS Sustain. Chem. Eng., 4, 6455-6462.

In the BMBF-funded project PyroLith, a methodical approach for the recovery of Li from NMC type LIB via a combined pyro- and hydrometallurgical process route is being developed. For this purpose, the cooling conditions and the chemical composition of the battery slags are optimized in the pyrometallurgical process step so that the whole Li content of the melt is enriched in the artificial, Li-rich compound lithium aluminate (γ-LiAlO₂). After comminution of the slags, the γ-LiAlO₂ is separated from the largely silicate slag matrix by flotation. The lithium is then leached out by hydrometallurgical processes and recovered as Li₂CO₃.

In order to achieve the project goal, extensive chemical and mineralogical analyses of the process samples are required, which are carried out as part of a method development at BGR. Because Li cannot be directly measured by conventional wavelength- and energy-dispersive X-ray spectroscopic investigation procedures, and amorphous components are only given as a sum in X-ray diffraction analysis, the use of several complementary analytical methods for sample characterization is necessary.

In the work presented here, it is briefly outlined how a Li- and Mn-rich slag from the simplified battery slag system Al₂O₃-SiO₂-CaO-MnO-Li₂O can be fully characterized chemically and mineralogically using QXRD, SEM-MLA, EPMA, XRF and ICP-MS. Furthermore, a rapid analytical tool based on UVC radiation or alternatively on µEDXRF is presented to determine distribution, crystal size, crystal morphology and relative content of the target phase γ-LiAlO₂ in the slags within a few seconds (UVC radiation) or within 3 hours (µEDXRF).

Zn-Pb deposits are host to a large proportion of worldwide resources of Ge and other critical metals. The Black Angel district in central West Greenland hosts several Zn-Pb occurrences, including the historic Black Angel mine, South Lakes and Kangerluarsuk, that show a previously unrecognized endowment of Ge and Bi (± Te) respectively. The carbonate-hosted MVT deposits at Black Angel and South Lakes show strong deformation and associated ore remobilisation at Upper Greenschist facies conditions (ca. 470°C), as indicated by graphite thermometry. Germanium occurs in tectonised and remobilised ore in the form of briartite, which is hosted in sphalerite and galena matrix. We studied how rock deformation and related remobilisation processes in these ore bodies lead to the redistribution of Ge and formation of briartite. Germanium was most likely exsolved from sphalerite as nanoinclusions of briartite during recrystallisation. Subsequent solid-state and fluid-assisted processes lead to formation of micrometre sized grains of briartite in sphalerite matrix, as well as up to millimetre-sized briartite aggregates. However, the nearby clastic-hosted SEDEX deposit at Kangerluarsuk shows native bismuth and tellurides hosted with galena, and no briartite or other Ge enrichment. Thus, two contrasting Zn-Pb systems with a different critical metal endowment are in close proximity to one another.

Laterite ore deposits in Brazil and other tropical countries contain approximately 70% of the world’s Ni and Co resources. High energy and/or reagent costs, accompanied by expensive equipment costs, are generally incurred when recovering Ni and Co via pyrometallurgy or high pressure acid leaching. Considering economic efficiency, the development of an integrated low-energy and environmentally benign biohydrometallurgical process for the recovery of these metals from laterite ores in Brazil is the aim of the German-Brazilian project BioProLat. Several acidophilic bacteria are able to use sulfur (S) as electron donor and couple the oxidation of S to the reduction of ferric iron, and are thereby capable of reducing the insoluble metal compounds to a water-soluble form. During this process sulfuric acid is generated, providing the acidic conditions that are needed to keep iron and other metals soluble. Stirred-tank bioreactor and percolation column laboratory experiments were used to optimize parameters including pH, temperature, aeration and a most suitable bacterial consortium for the bioleaching of Ni and Co. Stirred-tank laterite bioleaching at a start pH 1.5 under aerobic conditions with a consortium of different Acidithiobacillus thiooxidans strains resulted after 15 days in maximal 83 % extraction for both, Co and Ni, for 10 % (w/v) pulp density of a laterite sample from Barro Alto mine, Brazil. Eventually, the optimized process will be upscaled and reach pilot scale, transforming unexploited ores and limonite stockpiles into valuable resources, unlocking new reserves of raw materials through increasing recovery of metals from existing mines.

Epithermal ore deposits are important resources for various precious (e.g. Au, Ag) and base (e.g. Cu, Pb, Zn) metals. They form within the uppermost 1.5 km of Earth's crust by circulation of hydrothermal fluids through fractured and porous rocks in geothermal and volcanic systems. Many hydrothermal veins in epithermal deposits show evidence for pulsed ore formation events with high metal contents limited to distinct growth zones. As a particularly efficient mechanism for metal enrichment to economic grades, transport and precipitation of precious metals has been proposed to occur by isochemical contraction of a magmatic vapor phase from an underlying magmatic-hydrothermal system, where fluids can phase separate, followed by a second phase-separation event of near-surface boiling. Numerical models can provide unique insights into the temporal and spatial relationships of ore-forming processes. We use a model for magma reservoir growth to investigate the impact of sill injection rates on the hydrothermal system. The simulations with more episodic, low injection rates (<1.3 x10^-3 km³/y) result in a highly variable fluid plume which allows almost pure magmatic fluids to migrate to shallower and cooler regions, where they can phase separate and potentially form epithermal ore deposits. The modelling results point towards a relatively short time span of potential ore formation of a few thousands of years until the magmatic fluid plume retreats. Long-lived magma reservoirs which are forming at higher injection rates hamper the formation of high-grade epithermal deposits, but are more favourable for high-grade porphyry Cu deposits.

The Erzgebirge-Vogtland metallogenic province covers a wide variety of tin mineralization (greisen-, vein- and skarn-type) and represents one of the classic Sn regions in the world. The Gottesberg Sn(-W) greisen deposit is located on the western rim of the Eibenstock granite pluton. The multistage Sn mineralization of Gottesberg is closely spatial and temporal related to multiphase intrusions of subvolcanics and brecciation, controlled by a crosscutting area of major deep fault zones. For this work, lamprophyric dikes from latest drill core of Saxore Bergbau GmbH were sampled. Microscopic investigations were supplemented by the method of MLA (Mineral Liberation Analysis). Geochemical analyses of major and trace elements were performed. Previous work focused primarily on the Gottesberg Subvolcanic Suite (rhyolites and microgranites) whereby this work provides the first modern study of lamprophyres from the deposit and their age relationship to other magmatic events and the Sn(-W) mineralization. The porphyritic lamprophyres occur in dikes up to 3.5 m thick, carry xenocrysts of the granite, microgranite and rhyolite, and are partly strongly altered. Amphiboles were replaced by biotite. In the contact with the granite, the dikes form a chilled margin consisting mainly of biotite. Alteration phenomena on the groundmass and xenocrysts were studied. Cassiterite-quartz-sulfide veinlets and enclaves of granite and rhyolite in lamprophyric dikes provide information on the age position of the rocks. Overprinted lamprophyres show Sn and Rb contents >1,000 ppm and F contents up to 1.10 wt.%. Lamprophyre samples with high Zn contents (2.090-3640 ppm) show relatively high In contents (5-15 ppm).

The magmatic-hydrothermal transition is an important but poorly-understood process in the formation of Sn-W, Nb-Ta and Li deposits associated with evolved granites and pegmatites. Theory predicts that boron isotopes will fractionate between magma and fluid, so the magmatic-hydrothermal transition may be recorded in the borosilicate mineral tourmaline, which is widespread and common in these kinds of deposits. The key information needed to interpret the tourmaline record is the B-isotope fractionation between granitic melts and the fluids derived from them but former experimental studies on B-isotope fractionation between the relevant phases are not in agreement (e.g. Kowalski and Wunder, 2018, Maner and London, 2018).

This study fills this gap by an experimental, multivariant approach. We synthesized a glass of haplogranitic composition (Ab₄₀Or₂₅Qtz₃₅) and produced variants of water content (0, 4 and 6 wt%), aluminum saturation (ASI 0.7, 1, 1.3) and boron concentration (2 and 5 wt%). For each composition we determined the coordination environment of B in the glass and the fractionation of B isotopes between the respective melt and aqueous fluid at near-solidus temperature. The first part of the study was the chemical characterization and analysis of B coordination in the glasses. The NMR analysis of ¹¹B indicates that the coordination of ¹¹B is dominantly trigonal in all glasses, but there is an increase of tetrahedral coordination with increasing boron concentration and water content. Fluid-melt fractionation experiments are ongoing and first results will be presented.

South Harz Potash Limited (SHP) is a publicly listed company on the Australian Securities Exchange (ASX). Through its wholly-owned subsidiary Südharz Kali GmbH, the Company holds the Ohmgebirge mining licence in the north-western part of the Thuringian Basin, a region with more than 100 years of history of mining Permian potash deposits.

Based on the available historical exploration data, the potash resource at the Ohmgebirge was categorised by Micon International Co Limited in 2019 as an Inferred Mineral Resource in accordance with the guidelines of the Australasian JORC Code (2012).

In order to increase the level of geological knowledge and the confidence in the existing drill hole and assay database and to advance the project, two confirmation holes were drilled in 2022. The successful drilling demonstrated a good comparability of lithostratigraphic, mineralogical and geochemical data with the historic exploration data. Combining the existing and new data sets, the geological model has been updated, allowing an upgrade of a substantial proportion of the Ohmgebirge Mineral Resource estimate from the Inferred to the Indicated classification.

Currently, SHP is collaborating with experienced consultants to prepare a feasibility study which will consider all relevant technical, economic, social and environmental aspects of the project in order to transform the Mineral Resource to a Mineral Reserve according to JORC (2012). To increase awareness of the importance of mining local raw materials, we communicate transparently and regularly with the regional public and all stakeholders on our project advancements.

The United Nations Framework Classification for Resources (UNFC) is an assessment tool for mineral resource endowments, originally developed for side-projects concerning geogenic resources, such as mines. Given the integration of UNFC into the Critical Raw Material Act, it is crucial to develop a standardized classification method for secondary raw materials. However, the current framework lacks concrete guidance and primarily relies on mining sector definitions. This leads to the inconsistent use of various factors and methods in case studies, resulting in diminished comparability. To understand the requirements and challenges of the application on secondary raw material projects and address the recent assessment of aluminium as critical, a pioneering case study is conducted on a novel aluminium sorting plant using laser-induced-breakdown-spectroscopy to enable alloy specific sorting of old scrap.

The UNFC assessment bases on three criteria: "Environmental-Socio-Economic Viability," "Technical Feasibility," and "Degree of Confidence in the Estimate”. In this study the criteria are evaluated with newly developed and existing factors such as quantity, quality, supply continuity, technology, infrastructure, and socio-economic, legal and environmental aspects, using assessment methods like technology readiness level and material flow analysis. This results in a concrete guidance covering data demand, data sources and assessment tools.

The study's results will highlight the distinct requirements that differ from those of the mining sector and contribute to the development of a modified methodology. These advancements aim to enhance the applicability of UNFC, enabling comprehensive evaluations of different types of resources and projects and promoting informed decision-making towards a circular economy.

With its long mining history, Germany is a country with an important tradition in the field of mining science. The "Working Group on Geoscientific Aspects in Mining Areas" has been dealing with the remnants of mining and the resulting subsequent uses since it was founded in 1995. The task of the working group is to bring together geoscientists and other experts from the mining industry, from mining and geology-related administrative departments and research institutions for an interdisciplinary exchange of ideas and experience.

The first meeting of the Working Group on Mining Consequences took place in Upper Lusatia on the landscapes resulting from lignite mining. The thematic range of further events expanded to include ore, salt, uranium, hard coal and earths and stone mining, oil and natural gas extraction, and the search for a final repository for radioactive waste.

The meetings of the working group combine theory and application in a very practical and illustrative way. Thematically diverse technical presentations and a full-day excursion to geological outcrops, historical or operating mining facilities and post-montane landscapes are the basis for intensive exchange among the participants.

In 2023, the Working Group on Mining Consequences looks back on 51 successful meetings in different mining regions of Germany, attended by about 5,000 professional colleagues from the geo- and mining sector, nature and geotope conservation, geoparks and many other disciplines. A conference volume with excursion guide is published for each meeting in the EDGG series.

The transition towards renewable energy sources has led to a growing need for effective energy storage systems to ensure a stable and reliable power supply. Solar and wind power, although abundant, are intermittent, causing fluctuations in electricity generation. To mitigate this issue, energy storage solutions are required to store surplus energy during periods of low demand and release it during times of high demand. This research focuses on repurposing abandoned open pit coal mines as Hybrid Pump Hydropower Storage (HPHS) systems, where the mine pit functions as the lower reservoir.

The stability of the slopes in these repurposed mines is a critical factor for the successful implementation of HPHS. The presence of water in the lower reservoir and the potential inflow of groundwater play significant roles in determining slope stability. An analytical and numerical model has been developed to assess the slope stability in the selected mines for HPHS operations. Various factors, including fluctuating groundwater levels, reservoir filling levels, and different loading conditions, have been considered in the analysis.

The findings of this study contribute to a better understanding of the impact of these factors on slope stability in HPHS applications.

Nachdem die Kalidüngemittelproduktion in den 1860er Jahren in Staßfurt, im nördlichen Harzvorland, ihre weltweite Premiere erlebte, sich zunächst auf das sogenannte Nordharz-Kalirevier beschränkte, begann auf Betreiben des preußischen Bergbeamten Pinno - und entgegen der damaligen akademischen Lehrmeinung Ochsenius’ - schon in den 1880er Jahren die Erkundung der südlich des Harzes gelegenen Kalivorkommen. Die erste Bohrung Hochstedt wurde westlich Nordhausen bei Günzerode platziert und im November 1888 eingestellt ohne Kalisalze erreicht zu haben. Die zweite Bohrung bei Kehmstedt traf im Juli 1889 ein 63m mächtiges Kalisalzlager an. Bis November 1897 folgten weitere 64 Erkundungsbohrungen in über 50 Gemarkungen bis das erste - vom Preußischen Staat finanzierte - Bohrprogramm im November 1897 mit dem Nachweis der großflächigen Verbreitung bauwürdiger Hartsalz- und Carnallitit-Vorräte erfolgreich abgeschlossen wurde.

Bereits kurze Zeit nach der ersten fündigen Kalibohrung im preußischen Hoheitsgebiet des Südharz-Revieres startete auch die erste privatrechtliche Kapitalgesellschaft die Bohrerkundung auf Kalisalze im August 1891 bei Jecha, Fürstentum Schwarzburg-Sondershausen. Die Bohrung erreichte in 626,20m Teufe ein über 12m mächtiges Carnallitit-Lager, was für den Markscheider, Bergbauunternehmer und Brauereibesitzer Brügmann aus Dortmund als hinreichender Bauwürdigkeitsnachweis genügte, so dass bereits im Mai 1893 mit dem Teufen des ersten Kalischachtes im Südharz-Revier begonnen wurde. Die bergmännische Gewinnung der Kalisalze begann ab 1896 auf dem nach ihm benannten Brügmann-Schacht der Gewerkschaft "Glückauf" in Sondershausen, worauf rasch weitere Bergwerke folgten. Bereits 1914 verfügte das Südharz-Revier über 33 Schächte, zum Jahreswechsel 1924/25 waren es bereits 50 vollendete Schachtanlagen mehrerer Kaligesellschaften, die in der Folgezeit verschiedene, auch staatlich gelenkte Konsolidationen und Stilllegungen erfuhren.

Die Südharz Kali GmbH, eine 100%ige Tochtergesellschaft der South Harz Potash Ltd., eine in Australien gelistete Aktiengesellschaft, hat 2017 das Bergwerkseigentum (BWE) Ohmgebirge erworben und beabsichtigt dort die Gewinnung von Kalisalzen. Das BWE Ohmgebirge grenzt im SW bzw. W an die Grubenfelder der ehemaligen Kalibergwerke Bischofferode und Sollstedt. Dort wurden bereits Ende des 19./Anfang des 20. Jahrhunderts, zwischen 1956 und 1965 und in den 1980er Jahren in mehreren staatlich finanzierten Erkundungskampagnen wirtschaftlich interessante Kalisalzvorräte nachgewiesen. In den Jahren 2017 und 2019 erfolgte zunächst die Neubewertung dieser historischen Erkundungsdaten. 2022 wurden zwei neue Tiefbohrungen abgeteuft, durch die die Resultate unmittelbar benachbarter historischer Bohrungen aus den Jahren 1906 und 1983 bestätigt wurden.
Im Posterbeitrag werden die Erkundungsstrategie und die Resultate der jüngsten Bohrerkundung im Südharz-Kalirevier vorgestellt.

Field observations across the globe show that drainage reversal toward a cliff is a common type of drainage reorganization. Drainage reversal occurs when a channel reverses its flow direction by 180 degrees while exploiting its antecedent valley. In these settings, fluvial deposits of the antecedent, pre-reversal drainage potentially record valuable information about the process of drainage reorganization. However, such fluvial deposits are rare because they are typically eroded by the reversed channels.

We present a spectacular case of a reversed channel in the Negev desert, Israel, that forms a narrow canyon with several-meters high vertical walls exposing a sequence of fluvial deposits that reflect the reversal process. At the base of the sequence, a <1 m thick conglomerate layer is characterized by clast imbrication consistent with the westward flow direction of the antecedent drainage. Overlying the conglomerate, reddish fine-grained sediments (~1-2 m thick) indicate a decrease in flow energy, reflecting the reversal of the flow toward the current eastward flow direction. Paleosols and scattered calcite nodules within the sediment imply phases of soil development, most likely during a more humid climate than today. The uppermost layer (<1 m thick) consists of sediments of alluvial fans fed from the neighboring hillslopes, that play a key role in the development of the reversed channel through their avulsion cycling. Using geomorphic mapping based on high-resolution DEMs and preliminary dating results, we propose a holistic approach for better understanding the relationships between sedimentary systems, climate changes, and erosional processes in landscapes experiencing drainage reorganization.

Alluvial river adjustment occurs in response to altered sediment and water inputs, driven by both natural and anthropogenic climate change, changes in land use and/or land cover, and/or imposed by tectonic boundary conditions. This river response is ultimately reflected in the geometry of the bankfull channel, the planform characteristics of the river, and the longitudinal profiles of the mainstem river and its tributaries. This study utilizes analyses of river longitudinal profiles and provides a powerful tool to detect the change and extend it to long-term landscape evolution. Wickert and Schildgen (2019) developed the model, GRLP, to compute transient and steady-state solutions for the long-profile evolution of transport-limited gravel-bed rivers with self-forming channel-width adjustments. Following an analogous approach to that taken by Wickert and Schildgen (2019) and linking sediment transport and river morphodynamics, we developed a model describing the long-profile evolution of a transport-limited sand-bed river. This sand-bed model allows for planform adjustments as a function of excess shear stress (following Parker, 1978, and Dunne et al., 2018) thereby linearizing the sediment-transport response to changing river discharge. Ultimately, the resultant equations suggest a diffusive form for sand-bed river long-profile form and evolution. Both models were further built to work with the Landlab component library. Here, with these Landlab compatible models, we further present examples of sand- and gravel-bed river long-profiles under a variety of water- and sediment-supply boundary conditions, and present the transition into models of linked tributaries reproducing river-network evolution over both human and geological time scales.

The width of fluvial valley-floors is a key parameter to quantifying the morphology of mountain regions. Valley-floor width is relevant to diverse fields including sedimentology, fluvial geomorphology, and archaeology. The width of valleys has been argued to depend on climatic and tectonic conditions, on the hydraulics and hydrology of the river channel that forms the valley, and on sediment supply from valley walls. Yet, so far, a physically-based model that can be used to predict valley width is lacking. Here, we derive such a model and test it against three different datasets. The model applies to valleys that are carved by a river migrating across the valley floor, and includes the effects of uplift and lateral hillslope sediment supply. Valley width is controlled mainly by the mobility-uplift number, which is the ratio between lateral channel mobility and uplift rate. At high values of the mobility-uplift number, the valley evolves to the channel-belt width, which is the width of the area actively reworked by the river in an unconfined setting. At low values of the mobility-uplift number, valley width corresponds to channel width. Between these limits, valley width is linked to the mobility-uplift number by a logarithmic function. We compare the model to independent data sets of valleys in experimental and natural uplifting landscapes and show that it closely predicts the first-order relationship between valley width and the mobility-uplift number.

Any keen observer has noticed that valleys show a large variability in their shapes, explained by the incision and widening processes. However, valley widening processes and rate are still poorly documented while valley evolution has a key role in geomorphological processes (contribution to the formation of abrasion terraces and establishment of ecosystems) and global geochemical cycles (increase of carbon storage in wide valley and buffering sediment fluxes transported to the oceans). Given these issues, it is becoming truly necessary to better understand valley widening rate and its controls.

For that, we focused on several river valleys (in the Arequipa Province, Peru, and in the plateau of Valensole, France) and we have used and further developed the approach tested in northern Chile by Zavala et al. (2021). We collected samples from valley flanks to measure the millennial erosion rates, by using in-situ produced Beryllium-10 and Aluminium-26, and analysed 10-Be and 26-Al concentrations to estimate the local valley flank erosion rate.

We also extracted different factors that may control widening rate (valley width, slope of flanks and valley floors, incision and drainage area, etc) in order to compare these factors to 10-Be and 26-Al concentrations. Our preliminary results show comparable 10-Be concentrations along a single stretch of valley, except for several outliers, for different valleys in the Andes and France, indicating some robustness in the sampling method. These results are promising and will provide new answers, by integrating more metadata, about what controls the widening rate of valleys and how.

The depositional architecture and geomorphology of alluvial fans that have evolved in response to similar regional environmental conditions can differ strongly, implying that autogenic processes may play an important role and lead to similar cycles of fan aggradation and incision that may be difficult to be distinguished from the effects of tectonics or climate change. Here we present new data from two different Late Pleistocene (33-18 ka) alluvial fan systems in northern Germany. These fans formed under similar climatic and tectonic conditions, but differ in size, type, and drainage area allowing to estimate the role of climate and autogenic controls on flow processes, facies architecture, and fan-stacking patterns.

Sand-rich, sheetflood-dominated fans are related to larger, low-gradient fan catchments. Steep depositional fan slopes (5°-17°) favored supercritical flow conditions. Steep, dip-slope catchments enhanced stream gradients and promoted the transport of coarser-grained sediments. These fans have lower gradient slopes (2-6°) and are dominated by channelized flows, alternating with periods of unconfined sheetfloods. Fan onset and aggradation occurred in response to climate change at the end of MIS 3. Meter-scale coarsening-upward successions are characterized by sandy sheetflood deposits at the base and overlain by multilateral or smaller single-story gravelly channel fills are related to high-frequency climatic fluctuations or seasonal fluctuations in water and sediment supply. In contrast, the recurrent pattern of multistorey, multilateral, and single-storey channel bodies with a lateral offset to vertical stacking pattern most probably was controlled by autogenic switch in an avulsion-dominated system.

Reconstructing sea water temperatures from carbonate derived δ¹⁸O_C is a widely used approach in paleo-environmental studies. However, converting δ¹⁸O_C to water temperatures requires information about the isotopic composition of the sea water (δ¹⁸O_SW), which usually can only be estimated for paleo-environments. Especially in shallow marine settings δ¹⁸O_SW can potentially be altered by a strong seasonal variability of fresh water supply. Dual clumped isotopes (Δ₄₇+Δ₄₈) can be employed to determine seawater temperatures independent of δ¹⁸O_SW, as isotopic clumping is independent of the bulk isotopic composition of seawater.

In the current study we aim to resolve the seasonal variability of δ¹⁸O_SW by the combined measurement of δ¹⁸O_C and dual clumped isotopes (Δ₄₇+Δ₄₈) in Eocene bivalve shells (Venericor planicosta) from the Paris Basin. To determine seasonal variations and to detect annual extrema, δ¹⁸O_C was measured along the shell. Based on the δ¹⁸O_C record, annual extrema were resampled for dual clumped analysis.

The analysed bivalve revealed a pronounced seven-year seasonal cycle in δ¹⁸O_C, yielding an average annual amplitude of 2.5‰. Translating this seasonal range to sea water temperatures, applying a constant δ¹⁸O_SW, results in an annual temperature amplitude of ~11°C. The dual clumped isotope measurements, however, point to a more damped seasonal temperature range (~4°C) and a variable δ¹⁸O_SW with a seasonal difference of ~1‰.

The Δ₄₇+Δ₄₈-based seasonal temperature amplitude agrees with an Eocene warm-house climate and a considered weaker latitudinal thermal gradient. Reconstructed δ¹⁸O_SW exhibits high seasonal variability, indicating the periodic influx of isotopically lighter fresh water into the Paris Basin.

Sedimentary archives from marine sinkholes enable long-term reconstructions of past storm activity. In the last years, numerous cyclone-frequency reconstructions have been obtained from sediment cores collected in blue holes located in the circum-Caribbean region. Such structures work as sediment traps for allochthonous particles, mobilized through storm waves and surges from adjacent areas by passing cyclones. The 320 m wide and 125 m deep Great Blue Hole (Lighthouse Reef, Belize) is an outstanding cyclone-frequency archive worth exploring due to anoxic bottom-water conditions and the opportunity to recover annual deposits spanning the Holocene interglacial and even parts of the late Pleistocene. In June 2022, a 30-m-long sediment core (BH8) was extracted from the sinkhole and dated to 12.5 ka BP at its base. Sedimentological and palynological analyses point to an initial cenote-like setting that experienced a rising marine influence starting around 7.2 ka BP, which led to brackish and restricted marine conditions until 5.7 ka BP. Afterwards, full marine conditions have persisted in the Great Blue Hole to present day. Our sediment-core analysis resulted in a 12000-years-long paleoenvironmental reconstruction at annual resolution. Several warm climate periods of this timeline represent past equivalents for the current situation of rising ocean temperatures. In the SW Caribbean, cyclone frequency changed from a rather variable and less active stage (12.5-3.5 ka BP) to a more stable and active state (3,5-0 ka BP). This bipartite pattern is surprisingly best explained by latitudinal changes of the Intertropical Convergence Zone (ITCZ) from a northern towards a southern location.

The Layla Lakes (300 km S Riyadh) had been fed by fossil groundwater until they dried up in the 1990s due to agricultural water abstraction, revealing a series of 22 sinkholes. At their walls, well stratified to laminated sediments became exposed, unlocking a hitherto unexplored paleoenvironmental and paleoclimatic archive in the center of the Arabian Peninsula.

In November 2022, sedimentary logs were recorded, including on-site spectral gamma-ray and magnetic susceptibility measurements. From four sinkholes, >600 samples were taken to unravel the geochronological, mineralogical, geochemical, and palynological evolution of the lakes at high resolution. Lithofacies analysis shows changes between laminated lake sediments and weakly stratified sebkha deposits composed of sulfates (gypsum, anhydrite), carbonates, siliciclastic components, and bioclastic remains (shells, chironomidae tubes).

Initial radiocarbon dating indicates that the laminated lake sediments comprise a time interval from recent to 300 a A.D., suggesting at least partly varve-type sediments. The sebkha facies with short lacustrine intervals covers the entire Holocene. Different sections can be stacked together by high-resolution 3D-models, generated from a drone survey (cooperation with KAUST, Saudi Arabia). Based on field observations and first data analysis, a multi-stage paleolake model is suggested: Triggered by faults in the underlying Lower Jurassic Hith, anhydrite converts into gypsum, forming a topographic bulge and a sebkha environment. During fall of the groundwater level, sinkholes collapsed in its center due to phreatic dissolution, forming the groundwater-fed lakes. All sections show a pronounced cyclicity which will be further analyzed by high-resolution multi-proxy analyses.

Anthropogenic warming is predicted to increase the frequency and intensity of tropical cyclones, leading to severe damage and loss of life. However, projections based on historical observations are limited due to the lack of longer-term and spatially-resolved data. Here, we use the Toarcian Oceanic Anoxic Event (T-OAE) as a case study to investigate the link between tropical cyclone patterns and climate change. The T-OAE is a well-studied example of intense global warming and environmental change in Earth's history, characterized by a 7°C increase in sea-surface temperature and the common occurrence of tropical cyclones recorded in sedimentary deposits.

We collected sedimentary outcrop data along a 60 km-long transect, comprising 10 detailed sections along the paleo continental shelf in the central High Atlas in Morocco. We used sedimentary characteristics such as grainsize, texture, sedimentary features, and ichnofossils to identify storm-generated strata in offshore to lower shoreface settings, and extract paleo-tropical cyclone parameters. To constrain the age model, we used a cyclostratigraphic approach based on magnetic susceptibility datasets. By comparing the results to pre- and post-T-OAE time intervals, we gained insights into the frequency and intensity of tropical cyclones during this event and how they may have been affected by climate warming.

Our study highlights the potential of outcrop data to extract past storminess characteristics and test current model predictions on tropical cyclone patterns. By improving our understanding of how climate change affects tropical cyclones, we can better prepare for and mitigate the damage caused by these extreme weather events.

The last deglaciation is an ideal time interval to investigate the effect of climatic and oceanic disturbances occurring at high latitude on the hydrological regimes of the Mediterranean Sea. In particular, a series of disruptions of the Atlantic Meridional Oceanic Circulation (AMOC) has punctuated the transition from glacial to interglacial conditions, with the so-called 8.2 ka event being the youngest one. After the publication of recent results showing the existence of instable climatic conditions in the Dead Sea during the Younger Dryas (Müller et al., 2022), we examine here the environmental record during the 8.2 ka event to illuminate the effects of the background climate (colder to warmer) on hydrological distrubances linked to AMOC disruptions. We performed a coupled limnological and geochemical analysis of sediments deposited in the deeper part of the Dead Sea (ICDP site 5017A), which showed the occurrence of repeated mass wasting deposits related to intense erosive activity in the watershed of the Dead Sea. Newly-acquired neodymium and strontium isotopes also show a rapid change in sediment provenance and a hiatus in outcrop sequences from western lake shores suggests a drop in lake level at that time (Migowski et al., 2006). Ongoing classification of mass wasting events and the integration of other well-dated regional records and paleoclimatic simulations will provide additional insights on the erosional processes operating at that time, as well as the climatic regimes associated.

DeepStor-1 is the exploration well to the Helmholtz research infrastructure “DeepStor”. DeepStor focuses on the investigation of high-temperature heat storage marginal to the former oil-field “Leopoldshafen“. It is located about 10 km north of the city of Karlsruhe (Germany).

The DeepStor-1 well will probe marine to continental syn-rift sedimentary successions. It is planned to reach the Pechelbronn Group at 1‘460 m. Seismic investigation reveal a structurally undisturbed section that below 200 m depth covers the Landau, Bruchsal, Niederrödern and Froidefontaine Formations. Cores will be taken from the entire section below 820 m resolving about 6 Myr (about 26-32 Ma) of the Oligocene (about 23-34 Ma) and revealing an important geoarchive on regional and global signals, evolutionary trends of plate tectonics, paleolife, and paleoclimate. In addition to coring, the logging program is planned to include besides technical logging, a caliper-, self-potential-, temperature-, dual latero-, natural gamma spectrometry-, neutron-gamma porosity-, sonic-, elemental capture spectroscopy-, as well as image-logs in the sections 215-820 m as well as in the cored 820-1460 m section. Drilling of DeepStor-1 is planned between 2023 and 2024. Besides the interest of the Helmholtz Association in

1. the characterization of the subsurface by logging and coring,
2. the evaluation of the structural, hydraulic, and hydro-chemical set-up and the boundary conditions of the reservoir, and
3. short and long-term testing of hydraulic and thermal performance of the reservoir,

the well offers opportunities for more fundamental investigations on the climatic and geological conditions during deposition of the reservoir rocks.

We report abundant small calcareous mounds associated with fossilized kerogenous microbial mats in tidal-facies sandstones of the predominantly siliciclastic Moodies Group (ca. 3.22 Ga) of the Barberton Greenstone Belt (BGB), South Africa and Eswatini. Most of the bulbous, internally microlaminated mounds are several cm in diameter and formed at the sediment-water interface contemporaneous with sedimentation. They originally consisted of Fe-Mg-Mn carbonate which is now largely silicified; subtle internal compositional laminations are composed of organic matter and sericite. Their presence for >6 km along strike, their restriction to the inferred photic zone, and the internal structure suggest that mineral precipitation was induced by photosynthetic microorganisms. Similar calcareous mounds in this unit also occur within and on top of fluid-escape conduits, suggesting that carbonate precipitation may either have occurred abiogenically or involved chemotrophic metabolism(s) utilizing the oxidation of organic matter, methane, or hydrogen, the latter possibly generated by serpentinization of underlying ultramafic rocks. Alternatively or additionally, carbonate may have precipitated abiotically where heated subsurface fluids, sourced by the intrusion of a major Moodies-age sill, reached the tidal flats. In summary, precipitation mechanisms may have been variable; the calcareous mounds may represent “hybrid carbonates” that may have originated from the small-scale overlap of bioinduced and abiotic processes in space and time. Significantly, the widespread occurrence of these stromatolite-like structures in a fully siliciclastic, high-energy tidal setting broadens search criteria in the search for life on Mars while their possible hybrid origin challenges our ability to unambiguously identify a biogenic component.

We studied two fine-grained calcite hardgrounds (Hg1, Hg2) from the upper part of the Early to Late Cretaceous Natih Formation. Both hardgrounds occur in a 60-m-thick succession of limestones, comprising the Natih members C, B and the basal part of A. The hardgrounds of interest are positioned in the members C (Hg1) and B (Hg2) and typified by abundant borings of homogenous distribution, filled with dolomite. They occupy the upper part of a mudstone to wackestone bed (Hg1) and a wackestone bed (Hg2), respectively, above which the grain size increases. Field work, petrographic, microfacies and cathodoluminescence analyses, allowed us to shed light on the their unusual great thickness (75 and 100-120 cm, respectively) as the thicknesses of such fine-grained horizons may generally represent barriers for calcite-precipitating fluids. The logged section represents a protected/lagoonal environment with a relatively low sedimentation rate as indicated by the hardgrounds, peloidal limestones and bioturbation-related nodular bedding. The hardgrounds contain sponge spicules, which we did not encounter elsewhere. The two hardgrounds formed by minor sediment aggradation of locally produced mud-rich sediment, in which near-surface cementation was able to keep pace with aggradation. These conditions were met due to the Cretaceous calcite sea water composition, tropical climate, relatively low relative sedimentation rate and relative sea-level rise shifting the depocenter landward. Episodic sea-level rise was caused by regional plate convergence. Slab-pull and pulsed thrust-loading caused down-bending of the platform twice and formation of the two hardgrounds. Temporary down-bending events were followed by isostatic rebound.

Understanding ancient climate changes is hampered by the inability to disentangle trends in continental ice volume from records of relative sea-level change. As a unique coastal deposit in tropical and subtropical regions, beachrock has been proved to be reliable for constraining the glacial meltwater signal and, thus, the total volume of land-based ice in the Quaternary. However, beachrock is rarely recognized in the fossil record due to (a) the 2-dimensional distribution of beach deposits, as opposed, for example, to extended platform sediments, and (b) the fact that specific environmental conditions are required in order to lithify sediments directly at the beach.

By combing the stratigraphic architecture with petrography of characteristic cements, we show the first Ordovician beachrock from the Tarim Block, northwestern China. According to biostratigraphic data, a middle Katian (Upper Ordovician) palaeokarst surface is capped by a carbonate conglomerate beachrock, indicating a significant late Katian relative sea-level rise.

These beachrocks can be correlated with the onlap on the widespread subaerial exposure surfaces during deglaciation and post-glacial sea level rise. They formed in northwestern Tarim Basin after a pronounced stratigraphical gap reflecting the expression of a Katian glacial. We suggest that the beachrock ‘fingerprinted’ a strong melt-water pulse in high latitudes after this short-lived glaciation, which until now did not receive much attention in the scientific literature.

The world’s largest ammonite, Parapuzosia (P.) seppenradensis (Landois, 1895), has fascinated the world ever since the discovery in 1895 of a specimen measuring 1.74 metres (m) in diameter near Seppenrade in Westfalia, Germany. Subsequent findings of this taxon have been exceedingly rare and its systematic position has remained enigmatic. We have revised the historical specimens and documented abundant new material from England and Mexico. Our study (Ifrim et al., 2021) comprises 154 specimens of large (< 1 m diameter) to giant (> 1m diameter) Parapuzosia from the Santonian and lower Campanian, mostly with stratigraphical information. High-resolution integrated stratigraphy allows for precise trans-Atlantic correlation of these occurrences, and the Tepeyac section has become Associated Stratotype Section and Point for the base of the Campanian (Gale et al. 2023). It yields a rich macrofossil assemblage (Ifrim and Stinnesbeck, 2021) which is correlated to other parts of the world by the stable carbon isotope curve, and also to the successin of the German Münsterland Basin where the World's largest ammonite originates. The high- resolution correlation allows for further insight into the palaeobiology, evolution and dispersal of worlds largest ammonite.

The early Mississippian of the Aachen region is characterized by a tropical shallow-water carbonate succession, the so-called Kohlenkalk Platform. Establishing a second phase of intensive carbonate production, it follows on the Givetian to Frasnian biostromal buildups around the southeastern edge of the London-Brabant Massif. The timing and patterns of the development of these Carboniferous carbonates were studied, based on drill core Gressenich BK1. It was sunk by the Geological Survey of North Rhine-Westphalia in the core of the Burgholz Syncline and reached a depth of 100 metres. The borehole is located in the Vygen/Gressenich Quarry, which exposed and strongly tectonized Devonian strata were previously investigated by Reißner (1990). In contrast to the nearby active Hastenrath Quarry, the Palaeozoic part of the succession shows an inverted stratification. As Holocene sediments comprise a thickness of 7.30 m within the drill core, subsequent Devonian sedimentary rocks (mostly reefal limestones) occur up to a depth of 27.00 m. Followed by 12.40 m of black shale of unclear stratigraphic age, possibly the Frasnian Matagne Shale, all formations and subformations of the drilled Kohlenkalk succession can be easily subdivided by lithostratigraphy. Considering the regional stratigraphic schemes in the Vesdre Massif of eastern Belgium and referring to the formal lithostratigraphic concept of Amler & Herbig (2006), these are the Vesdre and Terwagne formations. The latter contains the Hastenrath (= Vaughanites Oolith), Bärenstein, and Bernardshammer subformations. Unfortunately, conodonts are rare or absent. In the case of the Vaughanites Oolith, reworking processes cannot be ruled out.

In northern Germany, Lower Cretaceous sediments are predominantly represented by CaCO₃-poor mud- and siltstones of up to 2000 m thickness, which become more carbonate-rich during the Albian-Cenomanian transition and even chalkier in the upper Cenomanian. The sedimentary system can be simplified considered as bimodally controlled by carbonate and fine-grained siliciclastics; in addition, some lithostratigraphic units are characterized by a high organic carbon content (Hoheneggelsen Formation, Barremian-Lower Aptian; Hesseltal Formation, Cenomanian-Turonian).
We present a 1500-m-thick composite record of late Berriasian to middle Turonian age based on 14 drill cores and about 4500 samples. All cores and successions are located in the larger Hanover area, which represents the depocenter of the North German Lower Saxony Basin in early to mid-Cretaceous times. Beside a recently published long-term carbon-isotope stratigraphy, we generated high-resolution calcium carbonate and organic carbon data, which nicely trace the lithostratigraphic units on formation and on member level, allowing for a more detailed characterization for most of the units. Only the Albian-Cenomanian transition from the Peine to the Herbram Formation is less well developed in the geochemical data.

The Danubian Cretaceous Group (DCG; Bavaria, SE-Germany) represents the deposits of one of the most pronounced sea-level rises in the Phanerozoic. Integrated stratigraphy (litho-, sequence-, and chemostratigraphy) and (micro-) facies analysis of the Lower Cenomanian–Middle Turonian strata of the DCG based on new drill cores from the north of Regensburg and the Grub section in the Bodenwöhrer Senke provides new insights in the process linked to the early Late Cretaceous sea-level rise.

Unconformably overlying Jurassic carbonates or Variscan granites, the Cretaceous succession includes the Regensburg (Lower Cenomanian–Upper Cenomanian), Eibrunn (uppermost Cenomanian–lowermost Turonian), Winzerberg (Lower Turonian) and partly Kagerhöh and Roding (Middle Turonian) formations. All lithofacies is of marine origin and consists of glauconitic sandstones, argillaceous marlstones, silty-spiculitic wackestones to marlstones, fine-grained (marly) sandstones, glauconitites and bioclastic wackestones. Five Cenomanian–Turonian sequence boundaries and their corresponding depositional sequences have been identified. Their correlative nature on an intra-basinal scale and beyond suggests a eustatic control of the depositional processes. High-resolution carbon stable isotope-based chemostratigraphy through the Cenomanian to Lower Turonian considerably improves correlation to nearby sections and European reference sections in southern England and France. A nearly complete record of the Oceanic Anoxic Event 2 (OAE 2) allows a detailed stratigraphic calibration of the Cenomanian–Turonian boundary interval and provides new insides into the environmental processes associated with OAE 2 in the Danubian Cretaceous Basin, including the first proof of the Plenus Cold Event from the region.

The widespread deposition of Lower Toarcian (Early Jurassic) black shales throughout NW Europe has often been associated with a global oceanic anoxia event, the Toarcian Oceanic Anoxic Event (T-OAE). However, sedimentary variations within the European sub-basins suggest a significant influence of regional effects, arousing interest in investigating regional variations in the NW European basin system. At the Hils syncline (Lower Saxony Basin), black shales of the Posdionienschiefer Formation have been studied extensively in recent decades, mainly focusing on the effect of thermal maturation on organic-rich sediments. However, under- and overlaying organic-lean clay- and mudstones are sparsely studied in this region.

This study investigates a continuous profile of Upper Pliensbachian to Upper Toarcian/Lower Aalenian deposits by combining samples from two boreholes from the Hils syncline, Wickensen and BO2.0, to establish a regional model for the deposition of Lower Toarcian black shales in this region. Nearly 200 samples were analyzed using a multi-disciplinary approach, including X-Ray fluorescence, C_org isotopic composition, Rock-Eval pyrolysis, and biomarker analysis.

The geochemical results suggest that the development of anoxia was closely linked to sea level and associated water circulation variations. Upper Pliensbachian and lowermost Toarcian sediments were deposited under oxic conditions associated with increased terrestrial influx and a low sea level. The overlying black shales (falciferum zone) are characterized by prevailing anoxia and photic zone anoxia and decreased terrestrial input, indicating a sea level rise. For the overlying Upper Toarcian Jurensismergel shales, ongoing sea-level rise is suggested, promoting less restricted water circulation and dysoxic conditions.

The sequence stratigraphic and facies analyses of the Lower Cenomanian to Upper Turonian core section HG 7025 provide a new standard section of the regional facies development and stratigraphic architecture in the so-called “Faziesübergangszone” (facies transition zone) of the Saxonian Cretaceous Basin. The section covers eight depositional sequences, divided by nine sequence-bounding sedimentary unconformities (SBs). The Lower Cenomanian depositional sequences DS Ce 1+2 and DS Ce 3 comprise the lower and upper fluvial Niederschöna Formation, separated by sequence boundary SB Ce 2. Above SB Ce 3, the Middle Cenomanian Wurmsandstein (DS Ce 4) displays the first marine influence in the succession. Intensifying this trend, the marine onlap continues during the early Late Cenomanian DS Ce 5, almost completely levelling the pre-existing paleo-topography. DS Ce 5 ends at SB Ce 5, representing a subaerial unconformity. Cenomanian marine onlap is completed by the plenus transgression during DS Ce-Tu 1, culminating in the lowermost Turonian Lohmgrund Horizon. The transition from Lower to Middle Turonian is marked by the regionally correlatable Bielatal Horizon of the Schmilka Formation (SB Tu 1). Both early Middle Turonian DS Tu 2 and Middle to early Late Turonian DS Tu 3 are defined by rapid sea-level rises and subsequent pronounced progradation phases. Separated by a subaerial unconformity (SB Tu 3), DS Tu 4 comprises a trans-/regressive cycle capped by SB Tu 4, marked by a sharp grain-size increase at the base of Sandstein c3. The Late Turonian DS Tu 5 is only represented by lowstand and early transgressive deposits.

The strata of the Danubian Cretaceous Group reflect dynamic depositional conditions in a peri-continental setting at the northern margin of the Alpine Tethys. From the Middle Turonian onwards, tectonic inversion along the Franconian Lineament started, reflected by the deposition of coarse-grained and extremely immature siliciclastics of the continental, more than 466 m thick Hessenreuth Formation, comprising the mid-Middle Turonian–Middle Coniacian depositional sequences DS Tu 3–Co 2. The composite section studied consists of successions cored by the deep Friedersreuth 10/1990 borehole as well as several shallow boreholes and outcrops. The >63 m thick Glashütte Member below 312 m ASL is characterized by beige-pink, conglomeratic sandstones alternating with thin brick-red, argillaceous-silty soil horizons. The Parkstein Member (312–390 m ASL) is dominated by several-meters-thick, partly inversely graded sandstone packages, interbedded by a few thin carbonaceous silt and clay beds with plant debris. The tripartite Friedersreuth Member (390–562 m ASL) starts with a cyclic conglomeratic-brecciform debris-flow unit, followed by a chaotic mud-flow unit, and is capped by predominantly fine-grained, plant-rich siliciclastics. The uppermost ca. 153 m constitutes the Hesserberg Member, i.e., mica-rich, coarse conglomerates that include meter-scale boulders. These alluvial subunits can be correlated to the mixed marginal marine / continental succession of the Bodenwöhrer Senke, ca. 60 km in the south, and the neritic deposits around Regensburg–Kelheim. Palynoassemblages are dominated by angiosperm pollen of the Normapolles group. Below 515 m ASL, the Turonian marker Complexiopollis christae occurs, while above 555 m ASL, Minorpollis minimus characterizes the Coniacian.

A lithostratigraphic unit is a stratum or body of strata that conforms to the law of superposition and is defined based on lithic characteristics and stratigraphic position. The stratigraphic concept relies on the assumption that younger rocks are deposited on pre-existing rocks during earth's history, and that individual sedimentary layers of rather constant thickness expand laterally. This working hypothesis has been successfully applied in many sediment studies and the results have been presented on numerous geological maps. A stratigraphic approach is problematic in regional metamorphic series, since the primary stratigraphy is converted into tectonic layering during metamorphic overprint. Using the Saxon Granulite Massif as a case study, this contribution aims to demonstrate the difficulty in applying lithostratigraphic methods to high-grade metamorphic rocks. We provide a critical discussion of the arguments that favour a lithostratigraphic model for the Saxon Granulite Massif in the light of the state of the art literature. High-grade metamorphic rocks should be primarily characterized based on their macroscopic appearance and further investigated using geochronological, petrological and structural methods. Absolute age constraints can be derived from radiometric dating methods, however, it should be critically evaluated if these results reflect a protolith age, a metamorphic crystallisation age or an inherited age. Many metamorphic terrains are dominated by rocks of different ages and thus conventional principles of stratigraphy cannot be applied.

Profound climatic and environmental changes at variable timescales are documented throughout the Late Triassic to Early Jurassic (c. 210-170 Ma) and were linked to the emplacement of large igneous provinces, tectonic processes, as well as transient climate fluctuations. Climate and environmental change triggered bio- and geosphere evolution, and impacted on sedimentary archives of marine and terrestrial basins. Most severe environmental change events, involving global carbon cycle and ecosystem perturbations, occurred at Triassic-Jurassic boundary (TJB; c. 201 Ma) and during the early Toarcian Oceanic Anoxic Event (T-OAE, c. 182 Ma).

We here discuss the differential response of depositional settings and organo-facies towards secular and transient environmental change along a basin-margin transect of the NW European Epicontinental Seaway (North German Basin), an expanded and intensively structured shallow shelf sea.

Stable carbon isotope values (d¹³C_org) revealed diagnostic trends that allow the precise intercorrelation along the transect, as well as correlation with far-apart sites. The TJB and the T-OAE are indicated by prominent negative carbon isotope excursions.

Programmed pyrolysis data indicate spatio-temporal organo-facies trends that on a temporal scale occurred in response to changes in deposition, such as climate and sea level evolution, while spatial pattern reflect basin morphology and paleobathymetry. Marine organic matter is best preserved at anoxic basinal sites, while marginal settings received increased land plant contributions and/or experienced more intense oxic degradation of marine organic matter. Substantial TOC accumulations occurred only in association with the T-OAE during high sea level and were most continuous at basinal sites.

The Axial Zone of the Pyrenees represents a window into the Variscan evolution of the northern Gondwana margin. One enigma of this evolution is the origin of the many and large granitoid intrusions and gneiss domes as well as the timing of their emplacement and deformation.

New zircon U-Pb data using laser ablation ICP MS indicate that granitoid plutonism is an almost continuous process over the entire Variscan orogenesis between 360 and 285 Ma that can be statistically constrained and shown for a number of these intrusions and domes. The Bassiés pluton is a key example which shows the oldest Carboniferous intrusive units with ages of 350 - 340 Ma, followed by the main intrusion phase between 330 and 320 Ma including the magmatic peak of 321 Ma. Two further age clusters occur around 314 to 300 Ma and around 285 Ma in the early Permian.

The polyphase development and in-situ melt recycling of the granitoids can also be inferred from core-rim relationships of zircon grains. There are zircons with core and rim ages of 346 and 326 Ma or 330 and 305 Ma, respectively. According to these results, it is required to revisit the mechanisms of pluton emplacement over such a long time span as well as the definition of the emplacement age. The youngest age is clearly not the crystallization age of the pluton, but plutonism is a long-lasting process that affects the Variscan crust over tens of millions or years, i.e. during the entire orogeny.

We present new results from a fission track (FT) dating approach on zircon and apatite from the Thuringian Forest, a prominent fault-bounded basement high in central Germany, and its southwestern periphery exposing Mesozoic strata. Samples were collected from exposures of igneous rocks as well as from lower to upper Permian (Rotliegend) continental red beds and volcanics recovered from a borehole southwest of the Thuringian Forest. Apatite FT ages range between 86 and 70 Ma, suggesting rock uplift associated with a well-documented and regionally important phase of NNE–SSW-directed intraplate contraction, resulting in spatially homogeneous removal of c. 3 km of Upper Palaeozoic to Mesozoic rocks. No change in apatite FT ages was detected across the regional-scale Franconian Fault system at the southwestern margin of the Thuringian Forest. Additionally, apatite FT ages of borehole samples southwest of the Thuringian Forest from depths between 9.6 and 2.7 km range from 57 to 18 Ma, suggesting post-Late Cretaceous cooling of this peripheral region. Our data hence support recent models of a continued large-scale domal uplift of Central Germany without verifiable or detectable involvement of individual faults.

The formation of crystallographic preferred orientations (CPO/texture) in sediments is often attributed to rigid grain rotation of minerals and aggregates, plastic-brittle deformation and dissolution-precipitation processes. Especially, clay minerals have a large shape anisotropy due to their platy habit. Here, we present an experimental approach in order to quantitatively explore the influence of particle settling and subsequent compaction in an undisturbed, ideal environment.

A powder of idiomorphic kaolinite grains was mixed with a fine-ground, illite aggregates in mass proportions of 0, 30, 50, 70 and 100 % in artificial seawater. The sludges settled in 80 cm high tubes. For each composition three samples were produced: Sedimentation-only and two drained compaction experiments (30 and 60 vol-%), which were carried out in a mechanical press with uniaxial load up to 0.4 MPa and 4 - 8 MPa. The CPO of clay minerals was measured using high energy X-ray diffraction at beamline P07b at Deutsches Elektronen-Synchrotron (DESY) and pole figure data was directly extracted using single peak evaluation.

The results indicate that sedimentation alone, can yield a strong texture of the clay minerals. The increase in texture strength (TS) is decreased at higher applied loads. TS is linearly related to shortening and porosity reduction. The kaolinite TS is inversely correlated with texture-inhibiting illite aggregate content which hampers further particle rotation. It is interpreted that the initial stages of settling and early rigid body rotation during compaction are thus the most important processes in the formation of a CPO in clay rich sediments.

The topography of the Rhenish Massif is known to be affected by Late Cenozoic uplift. Recent GNSS studies imply surface uplift rates of up to 1 mm/a, likely controlled by a mantle plume beneath the Eifel. Studies on Rhine River terraces show that central parts of the Rhenish Massif have been uplifted by 140 to 250 m since 700-800 ka. These figures correspond to a very low long-term average uplift rate of 0.1-0.3 mm/a, which decrease to even lower rates towards the margins of the Rhenish Massif. There, conventional geomorphic analyses, such as K_SN values, Chi-maps and basin asymmetries, show no evidence of vertical motions.

Field observations in several valleys of the Diemel river catchment in the northeastern Rhenish Massif show steeper west-facing topographic slopes compared with flatter east-facing slopes, suggesting asymmetric bedrock incision due to ongoing surface uplift. We analysed topographic river profiles on a regional scale in five catchments (Möhne, Alme, Ruhr, Diemel and Eder) using 1 m-resolution Lidar data to see whether they are affected by asymmetric river incision Our results show that only the S-N oriented streams cutting into lithologically heterogeneous rock formations show asymmetric incision. This pattern resulted from uplift and tilting of the Rhenish Massif towards the NE, causing differential erosion.

These preliminary results will be substantiated by a more regional study comprising the entire margin of the Rhenish Massif. We aim to investigate whether the slow vertical surface movements around the Eifel Plume could have led to asymmetric bedrock incision elsewhere, too.

Fabrics in the granulites of the Saxonian Granulite Massive (SGM) are interpreted to result from deformation related to early exhumation at deep crustal conditions, followed by subsequent shearing of the granulite roof against lower grade country rocks at retrograde conditions by top-SE shearing (e.g Reinhardt & Kleemann, 1994). For structural evidence and establishment of the rheological implications of such a multiphase deformation within the felsic granulites, detailed structural fieldwork and thin section scale microstructural analyses were carried out.

In the central SGM we observed a mylonitic foliation defined by interlayered quartz ribbons (20 vol.-%) and a homogeneous Qtz-Kfs-Pl-matrix that is transposed by a second mylonitic foliation towards the SE-rim, simultaneous with boudinage and proportion reduction of quartz ribbon (6 vol-%), and growth of biotite in the polyphase matrix. A NE-trending stretching lineation progressively rotates towards a SSE-trend. Quartz in the Qtz-Kfs-Pl-(Bt)-matrix generally has no CPO. Quartz ribbon’s (0001) CPOs change from two orthogonal, peripheral maxima to a central maximum.

Transposition of the foliation and lineation results from a change in the kinematics of flow at progressively lower temperature conditions, supported by a change from <0001> to <11-20> easy slip in the ribbons. Nevertheless, due to the generally high volume percentage of the Qtz-Kfs-Pl-(Bt)-matrix we assume diffusion creep s.l. involving grain boundary sliding to be the dominant deformation mechanism in all felsic granulites, suggesting a dominant linear-viscous rheology during the exhumation path.

References

Reinhardt, J., & Kleemann, U. (1994). Tectonophysics 238, 71–94, https://doi.org/10.1016/0040-1951(94)90050-7

The King’s Trough Complex (KTC) is a major canyon-like structure in the eastern North Atlantic and consists of several deep basins: The huge King’s Trough in the west is flanked by elongated ridges, while at its eastern opening the smaller Peake and Freen Deeps are separated by the Palmer Ridge. The King’s Trough is located in an area of elevated seafloor covered with numerous seamounts, which transitions to the Mid-Atlantic Ridge (MAR) flank toward the west. Here we present major and trace element and Sr-Nd-Hf-Pb isotope data from submarine volcanic rock samples obtained during RV METEOR cruise M168.

Whereas lavas from the eastern deeps show N- and E-MORB signatures and moderately depleted isotope compositions, samples from the western King’s Trough and surrounding seamounts display predominantly enriched OIB-like compositions. This geographic transition would be consistent with involvement of a mantle plume that was located beneath or near the MAR resulting in elevated seafloor of relatively enriched geochemical composition. The troughs probably formed subsequently by rifting and/or transtension when (36 to 42 Ma) the KTC area represented a temporary plate boundary between the Iberian and Eurasian plates. In the east, the KTC cuts into older (not elevated) crust, presumably formed prior to plume-ridge interaction, explaining why samples obtained from there possesses normal to transitional MORB compositions. Age and further isotope data are pending and will reveal if the ridges on the King’s Trough flanks represent younger, plume-related excess volcanism or simply the tops of tilted graben shoulders along the former plate boundary.

The Pustertal-Gailtal Line (PGL) belongs to the dextrally transpressive Periadriatic Fault system and forms the border between Southern and Eastern Alps. Although part of the ongoing convergence between Adria and Europe appears to be accommodated by this fault system, it reveals little instrumental and historical seismicity. In our study, we attempted to find evidence for past seismic activity along the PGL by investigating pseudotachylite occurrences.

We investigated an area of c. 19 km² to either sides of the PGL around Maria Luggau (Austria). We identified cataclasites and fault gouges along the fault core zone, from which we investigated only the cohesive rocks. Cataclastic, foliated Oligocene granitoids as well as garnet-mica schists of the Austroalpine basement are crosscut by cm- to dm-scale veins containing black fault rocks, which were sampled for further analyses.

Polarisation microscopy reveals that the vein-forming black fault rocks are often optically isotropic, testifying to their origin as quenched melts. Sharp margins of mm- to cm-sized injection veins against the surrounding host rock, well-rounded quartz and feldspar clasts, the absence of hydrous minerals in the matrix, as well as spherulites are further hints at a seismogenic origin of the studied fabrics. Some of the optically isotropic veins are internally foliated; their in-situ µ-XRF analysis of major element concentrations revealed chemical composition variations in the foliation. Even if this foliation might suggest overprinting by aseismic creep, our observations indicate a seismogenic origin of the studied fabrics as pseudotachylites.

The Bathymetrists Seamounts (BSM) form a 900 km long and 200 km wide volcanic chain of about 40 volcanic edifices within the eastern Equatorial Segment of the Atlantic. They are located between the Vema Fracture Zone in the north and the 4°N Fracture zone in the south (both transcurrent faults). Like other submarine chains east of the Mid-Atlantic Ridge, the BSM trend NE-SW. Many of those volcanic chains are intensively studied and attributed to hot spot tracks above mantle plumes. However, the BSM is much broader and strongly associated with faults. Still, it remains unclear if a mantle plume, decompression melting along fracture zones, or small-scale upper mantle convection caused these seamounts. We present new insights to the BSM based on about 80,000 km² high-resolution bathymetric data with 50 m spatial resolution, and 4,000 km of 2D seismic reflection data, collected during expeditions RV Merian MSM70 in 2018 and RV Meteor M152/2 in 2019. Seismic sections across the volcanic edifices allow a simple estimation of their relative age distribution, as it is inferred by the stacking pattern of the volcanic successions. Moreover, the structural pattern includes flower structures and indicates transtension. The single seamounts are arranged along E-W to NE-SW lineaments that can be explained by large-scaling Riedel shears. This Riedel shear pattern reveals a NW-SE orientated extensional local stress field during its generation in the Paleogene. Therefore, deep mantle plumes and shallower tectonics on a lithospheric scale could play an important role in the emplacement of the volcanoes.

The Christiana-Santorini-Kolumbo volcanic field, in the Aegean Sea, has hosted more than 200 explosive eruptions in the past 360,000 years, including the 1650 eruption of Kolumbo Volcano. In this contribution, we use the first 3D seismic reflection data collected over the submarine Kolumbo Volcano to explore active faulting and its relationship to volcanism. The 3D data enable us to extract useful fault attributes (strike, dip, dip direction) which can be used to decipher local stress fields. Our results reveal clear NW-SE directed extension around the volcano, consistent with published focal mechanisms from microseismicity. The data also provide exceptional 3D imaging of the Kolumbo Fault Zone, which lies ~6 km northwest of Kolumbo Volcano. Interpreted horizons through the Kolumbo Fault Zone reveal distinct relay ramps between overstepping normal faults. We suggest that magma ascent within the fault zone likely exploits enhanced vertical permeability associated with distributed deformation within relay ramps. Further research is required to understand the range of scales over which relay ramps could affect crustal permeability, and by inference magma ascent, in the greater rift zone.

Abstract: Twinned calcite occurs in calcite-bearing metagranite cataclasites within crystalline megablocks of the Ries impact structure, Germany, as well as in cores from the FBN1973 research drilling. The calcite likely originates from pre-impact veins within the Variscan metagranites and gneisses, while the cataclasis is due to the Miocene impact. Quartz in the metagranite components does not contain planar deformation features, indicating low shock pressures (< 7 GPa). Calcite, however, shows a high density (> 1/µm) of twins with widths < 100 nm. Different types of twins (e-, f- and r-twins) crosscutting each other can occur in one grain. Interaction of r- and f-twins results in a-type domains characterized by a misorientation angle of 35-40° and a misorientation axis parallel to an a-axis relative to the host. Such a-type domains have not been recorded from deformed rocks in nature before. The high twin density and activation of different twin systems in one grain require high differential stresses (on the order of 1 GPa). Twinning of calcite at high differential stresses is consistent with deformation during impact cratering at relatively low shock pressure conditions. The twinned calcite microstructure can serve as a valuable indicator of high differential stresses and sufficient confining pressure to prevent brittle deformation. The stress conditions at relatively low shock pressures (< 7 GPa) during impact-cratering are comparable to those at hypocentral depths during seismic rupturing in the continental crust. Therefore, comparable high-stress crystal plasticity of calcite might likewise be expected from fault rocks deformed at hypocentral depths.

The Koralm Complex in eastern Austria comprises various gneisses and eclogite lenses which record high-pressure metamorphism of Late Cretaceous age, acquired in an intracontinental subduction zone. The mechanism of exhumation of the Koralm Complex is either slab extraction or wedge extrusion. The present study aims at adding structural evidence to this problem. We studied an WSW-ESE-striking shear zone with SSE-dipping foliation and subhorizontal stretching lineation in the central part of the Koralm Complex. Based on quartz crystallographic preferred orientations (CPO) in gneiss, Krohe (1987) demonstrated sinistral shearing in this shear zone. We investigate microstructure and CPO of samples from the same shear zone using electron backscatter diffraction and photometry. Microstructures indicate grain-boundary migration, subgrain rotation, and static annealing. We find sinistral as well as dextral shear sense. This may either reflect flattening in the shear zone or two phases of deformation with contrasting kinematics. These two possibilities are discussed based on the textural data.

References

Krohe, A., 1987. Kinematics of Cretaceous nappe tectonics in the Austroalpine basement of the Koralpe region (eastern Austria). Tectonophysics 136, 171–196. https://doi.org/10.1016/0040-1951(87)90024-2.

Slab fluids, which are released by the subducting oceanic lithosphere through compaction and dehydration processes, are an essential mechanism for the transfer of volatiles from the slab to the mantle wedge. However, migration processes of slab dehydration fluids are not well understood yet, particularly with regards to transport mechanisms of redox sensitive elements such as sulfur.

In this study we investigated an eclogite-facies metabasalt from the South Tianshan Orogen, NW China, which contains several omphacite-dominated HP veins. Using mineral chemical analyses combined with in situ δ³⁴S measurements of pyrite, as well as isotope analyses of C, O, Sr and Pb in mineral and vein separates, we determined the metamorphic evolution of the studied sample and the speciation of sulfur during fluid infiltration and transfer.

Mineral chemical and isotopic compositions reveal seafloor alteration, affecting the protolith pillow basalt prior to subduction. This was followed by a two stage intra-slab fluid-flow under peak to prograde metamorphic conditions, forming the omphacite-dominated HP-veins. The first HP fluid originated from dehydrating ocean floor basalts, as documented by MORB-like pyrite δ³⁴S signatures. The second HP fluid composition suggests, instead, an origin from the basalt-sediment transition with negative pyrite δ³⁴S values of about -10‰. Pathways formed by the first fluid were reused and enlarged by the second fluid, which however also formed new pathways. This sample provides detailed insights into intra-slab fluid flow and fluid-rock-interaction processes at HP/LT metamorphic conditions and allows a better understanding of fluid transfer and sulfur speciation in subduction zones.

The Liguro-Provençal Basin, situated at the junction of the Northern Apennines and the Western Alps, formed due to the rollback subduction of the Adriatic-African plate underneath Europe and the subsequent upper plate extension in the Oligocene to early Miocene time. The opening of this basin was accompanied by the counter-clockwise rotation of the Corsica-Sardinia block relative to Europe until 16 Ma, with the basin widening towards southwest. It is yet unclear if the extension ever reached seafloor spreading with the production of oceanic crust, or whether it led to anomalously thin continental crust and/or to mantle exhumation. Although considered as tectonically inactive today, the Liguro-Provençal Basin shows active seismicity, indicating compression and potential basin inversion. Thus, it is crucial to better understand the opening of the basin and the tectonic inheritance due to rifting in order to better interpret the present-day seismicity. To this end, we compile existing geological and geophysical data, including recent data from the 4DMB project (“Mountain Building Processes in Four Dimensions”), to constrain the crustal and sedimentary thicknesses throughout the basin. We also focus specifically on two profiles in the NE (Corsica-Provence) and SW (Sardinia-Gulf of Lion) parts of the basin and compare these with the results of coupled thermo-mechanical and surface process modelling using Aspect and Fastscape codes. Finally, we discuss the effect of differences in various parameters, such as pre-rift crustal thickness, rift velocities and sediment supply, on rifting processes in the Liguro-Provençal Basin.

One of the major tectonostratigraphic characteristics of foreland basins is the transition from deep marine (i.e. flysch) to terrestrial (i.e. molasse) depositional settings. Several mechanisms have been proposed to influence this flysch-to-molasse transition, including slab breakoff beneath the adjacent mountain range. However, this coupling has not yet been assessed quantitatively. We hypothesize that isostatic rebound following slab breakoff can lead to a spike in tectonic uplift of the orogen, resulting in increased sediment supply as well as uplift of the foreland basin, thereby causing shallowing.

This study aims at investigating whether slab breakoff leaves a stratigraphic fingerprint foreland basin stratigraphic architecture. To this end, we combine 2D geodynamic modelling of slab breakoff with Alpine-inspired rheologies with forward stratigraphic modelling using GPM (Geological Process Modelling) software. In this context, we extract subsidence and uplift velocities along 2D profiles during slab necking- breakoff to account for (1) fast/slow breakoff and (2) different slab bending angles. Second, the extracted velocity fields are used as input for creating forward stratigraphic models (FSM), in which eustatic sea level changes are introduced to test whether slab break-off has a first-order control on foreland basin sedimentation. Erosion, transport and deposition of sediments are modelled as diffusional processes (i.e. gravity driven).

Preliminary results indicate that a pulse in sediment supply corresponds to onset of slab necking whereas breakoff yields a small pulse instead. This could imply that already during necking the orogen is isostatically uplifted to such a degree that sediment supply towards to foreland basin increases significantly.

Major faults such as the Periadriatic Fault and the Giudicarie Fault have been active in the past, and they have even been central features of the larger-scale deformation in the Alps. It seems that these faults are not active anymore though and we investigate why this is so by inspecting the orientation of the regional stress field which loads the faults mechanically. The orientation of maximum horizontal compressive stress (SHmax) is commonly estimated from in-situ borehole breakouts and earthquake focal mechanisms. Borehole measurements are expensive, and therefore sparse, and earthquake measurements can only be made in regions with many well-characterized earthquakes. Here we derive the stress-field orientation using stress-induced anisotropy in nonlinear elasticity. We measure the strain derivative of velocity as a function of azimuth. We use a natural pump-probe approach which consists of measuring elastic wave speed using empirical Green’s functions (probe) at different points of the earth tidal strain cycle (pump). The approach is validated using a larger data set in the Northern Alpine Foreland region where the orientation of SHmax is known from borehole breakouts. The technique is then applied to the Southern Alps to understand the contemporary stress pattern associated with the ongoing deformation due to the counterclockwise rotation of the Adriatic plate with respect to the European plate. Our results explain why the two major faults in Northeastern Italy, the Giudicarie Fault and the Periadriatic Line (Pustertal-Gailtal Fault) are currently inactive, while the currently acting stress field allows faults in Slovenia to deform actively.

Anatomy and internal structure of the Alpine orogen are difficult to decipher as structural information is usually limited to surface and seismic data. Seismic results very much depend on the elastic wave velocity model of the rocks. Simple velocity models depend strongly on the rock composition. In the investigated rock samples, phyllosilicates are by far most decisive for the elastic anisotropy. We present here the first results of fabric analysis in a N-S profile of the Innsbruck quartzphyllite and the Bündner schist from the northern part of the Brenner Base Tunnel Project in order to obtain a refined anisotropy and velocity model.

Phyllosilicate-rich sections were selected from borehole and tunnel samples, from which 1.5 – 3.5 mm wide columns were drilled out from layers of different composition and structure. The CPO of phyllosilicates and graphite was measured using high energy X-ray diffraction at German Electron Synchrotron (DESY) and European Synchrotron Radiation Facility (ESRF). Pole figure data were directly extracted using single peak evaluation and compared to the optical microstructure and compositional distributions using µXRF measurements.

Texture strength is variable along the section with peak values at the transition from the Innsbruck quartzphyllite to the upper Bündner schist. The texture strength correlates positively with the content and distribution of phyllosilicates and graphite. By measuring the smallest representative volume element, we estimate the upper bound of expected intrinsic velocity anisotropies. The effect of (micro)structure-based upscaling on these anisotropies will be discussed.

Detailed crustal structures and causative kinematic processes in the Alps continue to be a matter of ongoing research. Of particular interest is the crustal structure of the Adriatic indenter, the northern tip of the Adriatic plate that collided with and significantly deformed the Eastern Alpine Orogen in the Oligo-Miocene.

As part of the “Mountain Building in 4D” (4DMB/AlpArray) project, a high-density network of seismic stations was previously used to produce 3-D models of compressional wave velocity (Vp) of the crust and upper mantle in the Eastern and eastern Southern Alps using Local Earthquake Tomography (LET). This LET model shows a thickened high velocity zone within the lower crust beneath the Periadriatic fault, which is expected to relate to the local gravity field variations.

Here, we present results of gravity modelling using the IGMAS+ software and densities derived from the P-wave velocities of the LET model. Different possible empirical relationships between Vp and density are explored and compared to previous models as well as the AlpArray Gravity measurements to further constrain the present lithological and tectonic structures in the Eastern and eastern-Southern Alps. Strengths and weaknesses of the LET model and the gravity response of the derived densities, in particular regarding uncertainties of structures at greater depths, will be discussed.

We present ¹⁰Be-derived denudation rates from modern (n = 54) and buried sediment dated to 2.0–2.7 Ma (n = 3), and exhumation rates derived from published apatite fission track (AFT; n = 296) and apatite (U-Th-Sm)/He (AHe; n = 125) thermochronology from the Kyrgyz Tian Shan. Modern ¹⁰Be denudation rates are generally higher than the long-term AFT and AHe exhumation rates. On average, the highest ¹⁰Be denudation rates are recorded in the Terskey range, south of Lake Issyk-Kul. Here, ¹⁰Be-derived denudation rates from 2.0–2.7 Ma are comparable in magnitude with the AFT- and AHe-derived long-term exhumation rates, but modern ¹⁰Be-derived denudation rates are higher. We propose that denudation in the Kyrgyz Tian Shan, particularly in the Terskey range, remained relatively steady during the Neogene and early Pleistocene and increased after the onset and intensification of the Northern Hemisphere glaciations at 2.7 Ma due to glacial-interglacial cycles. Comparison with published data from the Pamir–Tian Shan region shows a spatial trend of decreasing modern denudation rates from west to east and an increase in the difference in magnitude between long-term exhumation rates and modern ¹⁰Be-derived denudation rates, suggesting that deformation controls denudation in the Pamir and Western Tian Shan, while farther east, the denudational response of the landscape to Quaternary glaciations becomes detectable by ¹⁰Be. We also find moderate correlations between modern denudation rates and topographic metrics and weak correlation between denudation rate and annual rainfall, highlighting complex linkages among tectonics, climate, and surface processes that vary locally.

The evolution and course of Himalayan rivers when exiting the orogen is controlled by the interplay between tectonics, climate, and associated sediment flux. We investigate these interactions by studying a Late Pleistocene deflection of the Sutlej River at the southern margin of the western Himalayan. This part of the Himalaya is also referred to as Kangra Recess. Late Quaternary faulting and folding along the Main Frontal Thrust and related back thrusts has created anticlinal structures in the south and piggyback basins in the north. Combined field observations and chronological constraints have shown that the anticline evolved as multiple fault segments, which grew through lateral propagation and led to the permanent deflection of the Sutlej River by ~ 50 km to the southeast. In this work, we present new luminescence and cosmogenic nuclide chronologies combined with previously published data to better identify the sedimentation history. Most importantly, we focus on the cause and final timing of the permanent river deflection. We show evidence for widespread aggradation and sediment deposition by the Sutlej River megafan and its tributaries starting before 47 ka and continuing until ~ 26 ka. Our 10Be and 26Al results in combination with available OSL data document the last widespread throughflow of the Sutlej at ~ 30-25 ka. We argue that a combination of climate and tectonic factors, especially
the variability of monsoonal strength, led to major changes in sediment supply at short time scales and therefore affected the course of the Sutlej River system.

The Himalaya is the highest and steepest mountain range on Earth and forms today efficient north-south barrier for moisture-bearing winds. 1D-thermokinematic modeling of new zircon (U-Th)/He bedrock-cooling ages and >100 previously published mica ⁴⁰Ar/³⁹Ar, zircon and apatite fission track ages from the Sutlej Valley document a consistent rapid decrease in exhumation rates that initiated at ~17-15 Ma across the entire Greater and Tethyan Himalaya and the north-Himalayan Leo Pargil dome. We observe a rapid decrease from >1 km/Myr to <0.5 km/Myr. We explain the middle Miocene deceleration of exhumation with major tectonic reorganization of the Himalayan orogen, probably coincident with the onset of basal accretion, which resulted in accelerated uplift of the Greater and Tethyan Himalaya. The period of slow exhumation in the upper Sutlej Valley coincides with a period of internal drainage in the south-Tibetan Zada Basin farther upstream, which we interpret to be a consequence of tectonic damming. Comparison with other data from the Himalaya and Southern Tibet along strike suggests that by ~15 Ma, southern Tibet was high, located in the rain shadow of the High Himalaya and eroding slowly for at least 10 Ma, before erosion accelerated again by ~5-3 Ma, most likely due to climatic changes. Our new finding document that the location of tectonic deformation processes controls the first order spatial pattern of both climatic zones and erosion across the orogen. Therefore, we think that the rise of Greater Himalaya is linked to the deceleration of exhumation in Southern Tibet.

Most islands host an endemic biota, i.e., present nowhere else on Earth. This is the case, for instance, of Madagascar. It has been shown that different populations of lemurs, endemic to the island, are mostly distributed along the watersheds surrounding Madagascar, creating a so-called micro-endemism, while the populations living on the high-elevated watersheds, on the central plateau, are not showing this micro-endemism. Here we wish to address the question whether there exists a correlation between the evolution of the landforms (i.e., the geometry of the watersheds) of Madagascar and the hybrid evolution of lemur populations? More broadly, can the tectono-geomorphic evolution of an island be advantageous or disadvantageous to the flourishing of micro-biodiversity?

To answer these questions in a quantitative manner, we combined a Landscape Evolution Model based on the Stream Power Law and taking into account flexural isostasy, with a speciation model. We first developed a morphometric index to differentiate between islands with a central plateau surrounded by smaller basins, like Madagascar, from conical islands, like Sri Lanka. We then predicted patterns of biodiversity as a function of the index value and its time evolution. We show that for the tectono-geomorphic evolution to influence patterns of biodiversity requires a specific range of model parameter values, in particular the parameters characterising dispersal and mutation. We finally used phylogenetic observations to constrain some of these parameters.

Changing climatic conditions cause alluvial rivers to aggrade and incise, which can result in the formation of multi-generational fluvial terrace sequences. Such records can be used to investigate past interactions between climatic conditions and the fluvial system and to predict channel responses to future climatic change. To accurately assess such interactions, precise dating of terrace sequences is vital. However, established methods such as ¹⁰Be exposure dating are costly and time intensive. Thus, they are impractical for application to spatially extensive areas and for establishing patterns of along-stream aggradation or incision.

An alternative approach of dating fluvial terraces is based on the degradation of the slope (riser) between successive terraces by down-slope sediment transport. Here we present a tool for analyzing high-resolution elevation profiles across alluvial terrace risers and inferring their age since abandonment, based on linear and nonlinear hillslope diffusion models. We extend this workflow to the analysis of DEM-derived riser profiles that can provide a greater spatial extent and resolution than GNSS profiles or exposure ages. A set of ¹⁰Be exposure ages dating back to ca. 1 Myr from terraces around the Río Santa Cruz, Patagonia is used for calibration and to test the method’s viability. Preliminary results highlight the importance of post-abandonment riser disturbances and variability in hillslope sediment-transport rates.

This technique provides a low-cost, spatially extendable way of dating fluvial terraces and analyzing landscape dynamics in fluvial systems. We are currently preparing to release an open-source Python package for performing these analyses.

Slab break-off is a geodynamic process in which the lower portion of a subducting plate detaches from its uppermost one. This process changes the force balance acting on the lithosphere causing tectonic uplift that can affect the sedimentary basin architecture by reducing the accommodation space and increasing the sediment supply due to source rejuvenation. While sediment supply intensity is commonly attributed to tectonic and/or climatic factors, recent studies have highlighted that the erodibility of the source area can have a significant effect on the timing of these signals.
To investigate this hypothesis, we modify the stratigraphic forward modeling software GPM (Geological Process Modeling software provided and produced by SLB), to consider the impact of topography-dependent steady flow. The simulation involved clastic deposition in a deltaic environment and included variations in source area erodibility, sea level changes, tectonic rates, and variable water discharge. Simulations were conducted with increasing complexity to quantify the sensitivity of catchment scale depositional rates to the aforementioned changes.

Southern Patagonia hosts uniquely well-preserved fluvial cut-and-fill terraces, formed along rivers fed by glacial meltwater, recording the onset of a regional phase of net incision. However, the timing and driving mechanism of incision remain debated. Published thermochronometric dating and modelling suggest increased exhumation in the last 1–3 Myr. Radiometrically dated basalt flows establish the existence of a eastward-draining paleo-valley with flows going existing terraces by 3.2 Ma. To better constrain the timing of Pleistocene river incision and landscape evolution in southern Patagonia, we present new cosmogenic ¹⁰Be exposure ages of terraces near Tres Lagos and the upstream reaches of the Río Santa Cruz (50ºS). Preliminary terrace surface exposure ages at Tres Lagos are between 70 ka–1.02 Ma, whereas upstream Río Santa Cruz terraces are between 390 ka and 1.04 Ma. The terrace age sequence shows that a phase of net incision started ~1 Myr after the widespread emplacement of basalts, concomitant with enhanced climatic forcing following the Mid-Pleistocene Transition. Our new exposure ages are in agreement with dated fluvial terraces of other Patagonian rivers, where ages range from 400 ka–1 Ma (47ºS; Tobal et al., 2021). Moreover, our record of Pleistocene landscape evolution is similar to other records throughout the Andes, where the timing of fluvial incision has been linked to enhanced climatic forcing after ~1 Ma. Our results point to a strong influence of the Mid-Pleistocene Transition on landscape evolution at a continental scale, notably including southernmost South America.

The measurement of ^239,240Pu in environmental samples can play a key role in investigating Anthropocene Earth (sub-)surface processes. As a consequence of atmospheric nuclear weapon tests conducted in the 1950s and 1960s, Earth’s outermost skin was supplied with fallout radionuclides (FRNs), providing distinct geochronological markers. The application of FRNs is well established, with ¹³⁷Cs being most commonly measured. However, ^239+240Pu activities are more decay-insensitive (t_1/2 ²³⁹Pu: ~24.1 ka; ²⁴⁰Pu: ~6.6 ka), there is less soil inventory contamination arising from nuclear power plant accidents than reported for ¹³⁷Cs, and only a few grams of sample material can be sufficient for a measurement. Ultimately, the (separate) quantification of ^239,240Pu inventories measured by Accelerator Mass Spectrometry (AMS) represents a further evolution step towards more precise measurements than achieved by other mass spectrometry or decay counting techniques.

The development of ^239,240Pu measurement capabilities at the Centre for Accelerator Mass Spectrometry (CologneAMS), University of Cologne (UoC), has given the go-ahead to exploit the wealth of possible ^239+240Pu applications to decipher modern Earth (sub-)surface processes in different settings. Based on tailored sample processing protocols applied at the Institute of Geology and Mineralogy and the Division of Nuclear Chemistry (both UoC), we present first results from a selection of ongoing projects. The sample processing workflow applied together with the AMS measurement precision achieved allows for resolving specific activities below ~5 mBq kg^-1. Accordingly, a spatial focus is laid on study sites where ultra-high precision of measurements is required (e.g., the Atacama Desert in northern Chile).

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The weathering of silicate rocks removes CO₂ from the atmosphere-ocean system on geological timescales but the time required for weathering intensity to respond to changes in climate is poorly constrained. The radiogenic isotopes of hafnium and neodymium are decoupled during silicate weathering with the isotopic composition of river clays being offset from bulk rocks. Here we examine the decoupled Nd-Hf isotopes of clays deposited in marine sediments from the northern Bay of Bengal near the mouth of the Ganga-Brahmaputra rivers. The sediment core (SO188 17286-1) covers the last 130 kyrs and has been used to study the past intensity of the South Asian Monsoon (SAM). The deviation of the Hf isotope compositions from the array defined by global river clays (ΔεHf clay), has a pattern of variability similar to the record of SAM intensity inferred from the reconstructed δ¹⁸O of seawater and δD of leaf waxes. These variations in silicate weathering intensity occur on timescales near 20 kyrs and appear to be paced by orbital precession. This suggests a strong, and rapid (on geological timescales), link between SAM hydroclimate and silicate weathering in this region. In contrast, changes in the source provenance of the clays as recorded by their Nd isotope signatures follow a glacial-interglacial pattern indicating either a sea level or global climate influence on changes in sediment transport to the shelf. This contrast demonstrates the great utility of ΔεHf clay to record changes in weathering intensity while directly accounting for shifts in sediment source provenance.

The deep Southern Ocean (SO) circulation is of major significance for understanding of the ocean´s impact on Earth’s climate as uptake and release of CO_­­­2 strongly depend on the redistribution of differently ventilated water masses.

Here, we present new authigenic neodymium isotope data (εNd) of the deep-sea sediment ODP1093 in the Southern Atlantic that reveals several systematic temporal glacial-interglacial changes in a range of 6.3 e-units. Assuming Nd-isotopes as mostly conservative tracer and neglecting possible reginal influences, the observed radiogenic εNd values of up to -2.5 during peak glacial periods suggest a predominance of glacial PDW at depths of >3 km. This results in a volume increase of carbon-rich water, aiding in atmospheric CO₂ drawdown during glacials.

The ability of εNd to trace water mass changes relies on the sensitivity of water masses to conservative Nd-isotope mixing. The εNd gradient ΔεNd is here defined as the North-South difference in εNd/10° latitude and is a measure for the sensitivity to changes in εNd signature over a given distance. Compared to further existing εNd records across the Atlantic Ocean the calculated mean εNd gradient for the Atlantic Ocean is approximately 0.89 ε-units/10° latitude and the εNd values of ODP1093 are constantly the most radiogenic. This suggests, that changes in ocean circulation during glacial-interglacial transitions are not purely induced by the Northern Hemisphere deep convection and southward flow but rather strongly influenced by equally strong changes of the SO circulation. This reinforces the importance of the SO in past and future climate changes.

In this contribution, we discuss our latest results from the project “Deformation Mechanisms along the Main Marmara Fault (DEMMAF)”, funded by the ICDP priority program of the German Science Foundation. The Main Marmara Fault (MMF), is the northern branch of the North Anatolian Fault along the Marmara Sea (NW Turkey). The MMF has produced several major earthquakes (M7+) in the past with a recurrence of about 250 years, and has not ruptured since 1766. The goal of the DEMMAF project is to investigate what controls the deformation mechanisms along the MMF, using data collected at the ICDP GONAF observatory (Geophysical Observatory at the North Anatolian Fault) and a combined work flow of data integration and process modelling approach.

Here, we use a forward numerical approach that implements frictional faults and visco-elastic off-fault materials to investigate the space- and time-scales of the long-term seismic behavior of the Main Marmara Faults and its main controlling factors. The MMF is modelled following a Coulomb frictional constitutive law and the spatially variable off-fault rock properties are derived from a data-integrative lithospheric-scale 3D structural model of the region around the MMF. The forward model is used to test the effect of varying boundary conditions (i.e. kinematic) and fault strength properties (i.e. coefficient of friction). Our modelling approach highlights the first order role of crustal rheology and fault-strength in the long-term behavior of the MMF (spatial distribution and recurrence of seismic events), as well as their potential to explain the along fault locking degree variability.

The erosive convergent plate margin offshore Costa Rica represents a seismic zone that produces high-magnitude earthquakes and tsunamis. The overriding Caribbean Plate is tectonically eroded by the subducting Cocos Plate, resulting in strong and widespread deformation of the upper plate. Differences in composition, compaction or deformation of the clay-rich marine sediments can have a significant impact on the strength of the continental plate, as well as the frictional behavior of the rocks entering the subduction channel.

Core samples from IODP Expeditions 334 and 344 of the Costa Rica Seismogenesis Project (CRISP) recovered from a depth range of 5–125 mbsf were experimentally deformed in triaxial tests under isotropic consolidated and undrained conditions at confining pressures of 400–900 kPa, room temperature, axial displacement rates of 0.0025–0.01 mm/min and up to ~50% axial compressive strain. Deviatoric stresses range between 127 and 418 kPa, pore pressure between 615 and 822 kPa. The samples exhibit internal friction angles of 8-42° and cohesion values of about 29-34 kPa.

The stress-strain records show exclusively structurally weak behavior and a higher consolidation of the upper plate compared to the incoming plate sediments. The sediments from prism toe and middle slope of the Caribbean Plate display systematically higher peak stresses despite a similar overburden. This together with the consolidation state indicate a loss of overburden, for example due to slumping at the continental slope. The mechanical properties might be crucial for fracturing and localized brittle deformation of the continental forearc during tectonic erosion.

As the world warms due to rising greenhouse gas concentrations, the Earth system moves toward climate sthistoricalhout historic precedent, challenging societal adaptation. One way to investigate these unprecedented conditions is to study past climates and ecosystems that share similarities to our current and future ones. One such period is the Eocene (~56 – 33 Ma), during which the climate changed from a hot-house to a greenhouse state, comprising a wide range of atmospheric CO2 concentrations. However, our knowledge of the Eocene climate evolution is incomplete because of a lack of terrestrial records covering the entire period. To address this gap in our understanding, we propose to obtain drill cores at Geiseltal in Eastern Germany.

This former lignite quarry is famous for its exceptionally well-preserved Eocene m. Still, itssils, but its potential as a climate archive has not yet been explored due to the lack of existing drill cores. By drilling a maximum of three cores, we aim to create a spliced 100-120 m long record comprising the entire Eocene archived in Geiseltal as an alteration of lignite seems intercalated with fluvial strata. High-resolution, multi-proxy analyses of the obtained sediments will allow the generation of a unique record of (sub)orbital climate variability under various atmospheric greenhouse gas concentrations. To advance this project, we welcome scientific input from a wide range of disciplines (e.g., stratigraphy, sedimentology, paleolimnology, paleobotany, paleontology, and organic/inorganic geochemistry) as well as are actively seeking interested groups and individuals to collaborate with us on this project.

Lake Bosumtwi, formed after a meteorite impact at ~1.07 Ma, contains a sedimentary archive that yields an excellent high-resolution record of climate- and environmental change in Sub-Saharan West Africa. The region is highly susceptible to climate changes due to shifts of the tropical rain belt and variation in dust dynamics in the tension field between the North African Monsoon (humid, wet) and the Harmattan (dry and dusty winds from the Sahara). Consequently, Lake Bosumtwi has been intensively studied and in 2004, supported by the International Continental Scientific Drilling Program (ICDP), sediment cores were recovered and downhole logs were performed that allow for the analysis of the complete ~300 m lacustrine sequence. However, detailed climatic and environmental reconstructions for the record are incomplete, mostly due to the absence of a robust age model prior to 500 ka. In 2022, we conducted core scanning natural gamma ray measurements for the ~300 m lacustrine sedimentary sequence. Based on the resulting data, we are generating a correlative age model that is tested by cyclostratigraphic tools and that can be directly compared to the available independently dated sections, but extends farther back in time. Our age model will provide critical chronologic context for the numerous existing and new proxy data that facilitate a study of changes in climate, environment, and ecosystems. This will allow a robust framework to analyse climatic interferences with archaeological findings that might shed new light on habitat availability for our ancestors in tropical Western Africa.

Ferruginous conditions prevailed in the oceans through much of Earth’s history. However, past biogeochemical cycling inferred from mineral components identified in ancient iron formations remain poorly understood in terms of microbial processes prior to lithification. In Lake Towuti, Indonesia, ferruginous sediments sink through a stratified water column and are deposited under anoxic conditions that mimic the Earth’s early oceans, thereby allowing the study of both geochemical conditions in pore waters and long-term diagenetic evolution of its 1 Ma stratigraphic record.

We combined detailed pore water geochemistry and stratigraphic proxies with scanning electron microscopy imaging of authigenic phases. Although variability in elemental profiles attests to climate- and tectonic-driven processes along the 100-m-long sediment sequence, deposition of ferruginous minerals appears transient as particulate iron, reworked from surrounding lateritic soils, undergoes partial dissolution-precipitation during sinking and after burial. Minerals found to form in situ included magnetite (Fe₃O₄), millerite (NiS), siderite (FeCO₃) and vivianite (Fe₃[PO₄]₂ ∙ 8H₂O). Acicular millerite aggregates overgrown by siderite and vivianite indicate that they directly precipitated from saturated pore waters (Ostwald ripening). This also suggests that these mineral phases may constitute a diagenetic sequence stemming from the progressive consumption of terminal electron acceptors with sediment organic matter remineralization during shallow burial. Thus, we consider that these minerals act as biosignatures of redox processes driven by autochthonous sedimentary microbial populations that actively control pore water geochemistry after deposition, thereby differentially imprinting the stratigraphy of bulk sediment during burial.

To investigate the interior structure, dynamics and evolution of terrestrial planets, numerical models of varying complexity have become an essential tool for many researchers. Modelers often struggle with outreach and accessibility, especially when the demographic includes students and scientists who are less versed in programming and modeling. To provide easily available teaching material, we have compiled a collection of several codes developed at our institution.

Firstly, we present an updated Version of the code CHIC, which is a collection of applications, spanning 1D parameterized interior structure and thermal-evolution models to 3D thermo-chemical convection models. The code will now be published under an open-source software license. The release will include an updated documentation of the code. Once released, we plan to update the codebases, if sufficiently impactful changes have been implemented.

Furthermore, we will release multiple Python codes, mainly as teaching material. These will include models of:

- Tidal heat dissipation, for variable planetary systems.

- Interior structure in 1D, based on the planet’s properties.

- Thermal evolution in 1D, based on interior structure and tectonic regime.

- Simplified 2D thermal convection with temperature- and pressure-dependent viscosity.

Instructions on installation, application and evaluation, are presented in short tutorials. We also provide several educational examples and showcases of common benchmarks. The goal is to create a framework for our institute to publish software related to modeling of planetary interiors. The demographic includes students, teachers and scientists, as the codes range from educational material to advanced scientific models.

Currently, no search engine is available for specific and easy searches of published research datasets stored in institutional repositories. Most commonly, primary research data in institutional repositories are accessed via its Digital Object Identifier (DOI), which must be known.

The global findability of research data can be increased by mapping its metadata to a search tool that allows finding and accessing information from a single search point. For this purpose, we mapped the TRR170-DB planetary data repository (https://planetary-data-portal.org/) with its XML metadata to the search engine PRIMO via the OAI-PMH method. PRIMO is the central search interface of Freie Universität Berlin for searching and accessing local and external resources. Metadata mapped to PRIMO can be found by global search engines such as Google.

Data in the TRR170-DB repository reflect the different methods and approaches applied to investigate planet formation in the collaborative research center ‘Late Accretion onto Terrestrial Planets’ (TRR 170). Datasets are stored in open electronic formats such as csv (tables), pdf (text), and jpeg and tiff (images). Once a dataset is published, the repository guarantees archival and long-term access to the dataset with a DOI persistent identifier. At present, most datasets are in the public domain and represent replication data of peer-reviewed articles which appeared in international journals since 2016. PRIMO’s harvesting of TRR170-DB metadata ensures that the datasets remain easily accessible to the global community in the long term while providing a setting that amplifies the use of best practices and collaborative and interdisciplinary research.

The mission of the Helmholtz Metadata Collaboration (HMC, https://helmholtz-metadaten.de/en) is to facilitate the discovery, access, machine readability, and reuse of research data of the Helmholtz Association. Concepts and services are developed and established, allowing the enrichment of research data with standardized metadata in the various phases of their creation. The aim of HMC is to co-ordinate these services with the national and international scientific community in order to establish widely accepted practices in the handling of research data.

In the Earth and Environment Hub, we are in the process of setting up a transparent virtual round table where all communities can come together to decide which guidelines are recommended for the Helmholtz Association. Jointly agreed principles are discussed and agreed in a moderated co-design process.

Primary stakeholder profile

• Infrastructures – leadership, technical personnel organising, standardising, and sharing their (meta)data
• Data stewardship teams - these include personnel working for infrastructures, libraries, or thematic (meta)data management solutions/services
• Personnel in research groups working to standardise and curate (meta)data

In this presentation we will introduce to the current HMC activities and outcome: Our process for developing a guideline is planned as a coordinated procedure. For every single implementation guide, we go through the same questions, up to tests - based on use cases and definition of abstract test classes, in order to be able to validate the implementation. Our planned results are recommendations and detailed implementation instructions that enable interoperability - not only in the Helmholtz Association, but also in national and international communities.

The seismic wave velocity configuration of the mantle provides constraints on its thermal and hence density structure, although the proposed methods of wave velocity conversion differ significantly. The V2RhoT_gibbs is a Python tool that allows converting mantle seismic velocities to temperature and density using a Gibbs free energy minimization algorithm applied to a defined mantle chemical composition to guarantee thermodynamic stability of the correspondingpressure (P) and temperature (T) dependent phase and mineral assemblages. Alternative methods, in contrast, start the conversion process with a pre-defined, P and T independent mineralogical composition, while yet other conversion methods involve a set of empirical equations. To better understand the differences between these conversion approaches, we have applied different methods to a shear-wave velocity tomographic model of the mantle below the South China Sea region. The resulting thermal fields are compared regarding the depth of the 1300 °C-isotherm which is a proxy of the lithosphere-asthenosphere boundary. In addition, we present the conversion results in terms of their respective gravity responses. This sensitivity analysis has important implications for better understanding the thermomechanical state of the lithosphere in the region.

The deep thermal field in the continental lithosphere varies significantly depending on the age of the lithosphere, its tectonic setting and the time since the last tectonic event. Accordingly, orogens with a thickened radiogenic crust will be hotter in their crust than cratonic areas that had billions of years time to equilibrate after the last tectonic event. Areas affected by continental rifting and passive margins also may be characterized by specific lithospheric configurations and a distinct geothermal fingerprint. Using data-integrated models of different continental areas we evaluate the first-order controlling factors of the related threedimensional temperature distributions. We find that the resolution of subsurface heterogeneities and the consideration of the appropriate heat transport mechanisms are key in predicting the characteristics of the deep thermal field. Accordingly, the superposed effects of varying thermal conductivities, contributions of radiogenic heat and variations of the thermal lithosphere thickness together result in setting-specific background 3D thermal fields. These effects are superposed by the effects of coupled fluid and heat transport in the the upper few km of the crust. Knowing the first-order characteristics of the local thermal fingerprint is key for geothermal exploration but also for estimating the expected mechanical thickness as well as the nature and magnitude of seismicity.

Earthquakes are a direct response to the Earth’s state of stress, which is one of the key ingredients controlling the lithosphere rheological behavior. To first order, the total in-situ stress is a function of two main co-players: the long-term tectonic stress, and the short-term (seismic cycle) stress transfer. Despite their diversity in temporal and spatial scales, these components are not mutually independent, but they do interact in the final rheological configuration of the lithosphere

Understanding the relative importance of different tectonic loads and how the stress is transferred is of high relevance for robust earthquake simulators. As the stress transferred to a fault affects its mechanical behavior, it has a direct control on its potential to generate earthquakes.

Recent studies suggest that the regional tectonic environment surrounding the faults (e.g., off-fault lithology, lithospheric structure, and degree of coupling between crustal and mantle domains) can influence fault behavior. However, the importance of such heterogeneities in modulating background seismicity needs to be properly evaluated to unveil the behavior of these complex systems.

3D data-integrative and gravity-consistent models are useful tools for characterizing such lithospheric-scale heterogeneities, and ultimately, to analyze their potential relationship with background seismicity. In this contribution, we present the preliminary results of a 3D lithospheric model of the southern San Andreas Fault system, where the wealth of available data was considered. We demonstrate that this is an important step towards the calculation of the background off fault stresses due to local loadings, which likely influence background seismicity.

Seismic tomography provides important data to understand the physical properties (temperature, density) of the lithosphere and upper mantle. These physical properties are crucial for understanding e.g., strain localization, geothermal potential. However, interpreting tomography models in terms of composition and temperature conditions is highly complex and non-unique. There are mainly two approaches to interpreting seismic tomography models: empirical and thermodynamics-based. In the empirical approach, the tomography models are calibrated with respect to known temperature distributions, such as those derived from age-dependent oceanic lithospheric thickness or heat flow models or temperatures derived from mantle xenoliths in the continental regions. In contrast, the thermodynamics-based approach involves taking into account the composition of the minerals or deriving it from bulk-rock chemical composition using Gibbs-free energy minimization. Recently, a new approach has emerged that combines the second approach with geophysical (potential fields, topography) and seismological data (surface wave dispersion curves). However, this method assumes a steady-state temperature distribution, limiting its ability to infer the second-order temperature and density distribution. To address these challenges, a new thermodynamics-based conversion tool called V2RhoT_gibbs has been developed. This tool is based on open-source Python libraries and coupled with the Gibbs-free energy minimization algorithm Perple_X. It does not assume any thermal state and, using bulk-average chemical composition, derives the temperature and density distribution. Output from this tool could be easily used to incorporate e.g., as voxel in gravity field interpretations, or as lower temperature boundary condition to compute the thermal field.

Throughout history, humans have modified the landscape by farming, extracting natural resources, and deforestation. However, it is not fully understood to what extent such activities have changed vegetation structures and potentially caused accelerated soil erosion. In this study, we investigate the effects of human activities on vegetation and erosion rate changes on the island of Elba, Italy. Previous geoarchaeological studies succeeded in reconstructing human-environmental interaction in the past and providing an independent reference frame for the current study. Hence, we hypothesize that intense iron production on Elba since the 6th century BCE, first by Etruscans, and later by Romans, was accompanied by deforestation and thereby caused increased soil erosion. To test our hypothesis, we collected sediment samples from modern streams and from existing floodplain sediment cores to reconstruct the millennial-scale and more recent changes in landscape-scale erosion rates, and in vegetation and hydrology by means of leaf wax isotopes (d²H, d¹³C). We use in situ cosmogenic ¹⁰Be and ¹⁴C produced in quartz to obtain erosion rates. The different half-life of these two nuclides (~1.4 Myr for ¹⁰Be and ~5.7 kyr for ¹⁴C) makes them sensitive to changes in erosion rates that occur on human time scales. ¹⁰Be results indicate relatively uniform millennial-scale erosion rates on the order of 0.04 mm/yr across the eastern part of the island, where we collected most of the samples. We expect that the combination of these methods will reveal the impact and patterns of human-induced soil erosion in Elba.

Rock art is a common cultural manifestation throughout Colombia. Here the Painted Stone of Aipe represents a striking archaeological evidence as an outstanding masterpiece of pre-Hispanic rock art. Several pectorals of different shapes are observed as a central motif used by the pre-Hispanic communities of Quimbaya, Tairona and the southern tribes. In addition to the pectorals, the stylized devil or monkey is seen in various combinations along with nose rings, fishhooks, bead necklaces, pendants, and rattles, among others. The substrate of the Aipe Painted Stone is a yellowish sandstone of oval shape and the low-relieve carvings are mainly on the longer SE-side of the stone block. This study aims to assess the different decay phenomena affecting the ~500-year old pre-Hispanic rock art carved on the sandstone block which is at an altitude of 370m on a main road near the Magdalena River. The artwork has important conservation problems mainly due to weathering creating a complex set of mechanical, chemical and biological processes on the rock. In the sandstone, the ~0,1 mm quartz-grains (45%) and foraminifers (15%) are mainly cemented by cryptocrystalline SiO₂; also phases like phosphates, clays, micas, opaques and a high open porosity of 15 % occur, enhancing chemical dissolution and precipitation of Fe-oxides. Among the main identified deterioration agents are water flows and humidity changes, solar radiation, abrasion caused by dust and sand carried by the often strong wind, internal pressure variations due to temperature variations and salt migration, plants and microorganisms, but also anthropic interventions.

In late 2020, an approximately 650 m long core was drilled at Prees within the Cheshire Basin, England, as part of the ICDP project JET (Integrated Understanding of the Early Jurassic Earth System and Timescale). The main objective of this project is to obtain a complete and continuous sedimentary archive of the Early Jurassic. The Early Jurassic (~200-175 million years) was a period of extreme environmental changes, which will serve as an analogue for present and future environmental change. The project aims to provide a reference record for an integrated stratigraphy (bio-, cyclo-, chemo- and magnetostratigraphy) of this period.

Analysis of geophysical borehole logs will allow the description of sedimentary cycles related to orbital parameters and paleoclimatic history if depositional environment and sedimentation rate permits. Here, downhole logging data from the Prees-2 borehole are used to construct a floating astronomical timescale for the Sinemurian stage, contributing to an integrated timescale for the Early Jurassic. Cyclostratigraphic methods, including a statistical and a visual approach, lead to preliminary durations for the Sinemurian stage of ~6.2 and 6.8 million years, respectively.

The last of a total of three main subsidence episodes of the northern Upper Rhine Graben took place during the Pliocene to Quaternary and allowed the accumulation of thick sedimentary sequences that can function as excellent data source for paleoclimate reconstructions. A 323 m long sediment core drilled in 2020-2021 near Riedstadt-Erfelden (~14 km WSW of Darmstadt) is therefore likely a high-resolution geoarchive documenting climate dynamics during the Plio-Pleistocene epochs. However, so far, the chronostratigraphic framework is based only on lithostratigraphic assignments. This study presents inclination values and magnetic susceptibility obtained from whole-core measurements and discusses initial stratigraphic ideas based on the resulting preliminary magnetic polarity stratigraphy and cyclostratigraphic assessments of the ‘Riedstadt-Erfelden’ core. Our results will be used to study the completeness of the geological record and will enable comparisons to be made with the cores investigated through the Heidelberg Drilling Project. Our aim is to verify the suitability and significance of the ‘Riedstadt-Erfelden’ core as geoarchive for Plio-Pleistocene climate dynamics in Central Europe.