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.