Geological and lithogeochemical characterization of Slovenian dolomites including Mg extraction tests

European industry is highly dependent on mineral raw materials, and most of them are imported from outside of the EU. Due to global geopolitical situations the supply of raw materials can be interrupted, which can drastically affect standard of living of EU citizens. A number of different raw materials will be needed for the EU's green transition. The EU commission is updating and upgrading the list of critical raw materials, which consists of minerals that are highly economically important for the EU industry, and for which the supply is at risk. One of such commodities is Magnesium (Mg). Due to its light-weight Mg is mainly used in aluminium and other alloys. It is also suitable for battery production and in a variety of applications, including transport, packaging, and the construction. There is no production of Mg in the EU, and most of it is imported from China. Mg is a metal which is produced from brines, or from different minerals (serpentine, magnesite, dolomite). Since Slovenia is rich with carbonate rocks, thick deposits of relatively pure dolomites are widely present, the obvious question arises – can they be used for Mg extraction and is our knowledge about this resource sufficient? Carbonate rocks in sedimentary basins are reactive and they keep a record of complex histories of events associated with fluid flows in these basins, including processes of dolomitization. During hydrothermal dolomitization, processes such as recrystallization and chemical alterations influence matrix-replacive dolomites. Consequently, dolomites exhibit distinct chemical signatures, which can identify properties of basinal fluids triggered by distinct tectonic episodes and associated volcanic activities and can therefore contribute to the geological knowledge about evolution of the study area. Subsequent successive recrystallizations in dolomites often completely destroy biogenic indicators of their age (fossils). The project will importantly contribute to developing of the scientific field by testing whether chemostratigraphic methods of dolomite datation is viable. To fully accomplish these goals Slovenian dolomites from Late Permian to Cretaceous will be investigated. The number of sampling sites inside each geological formation of dolomite rocks will be sufficient to determine statistical trends and evaluate lateral and vertical variations. Analysis will include detailed elemental composition (including trace and rare earth (REE) elements), and sedimentological and mineralogical characterizations. Detailed microstructural investigations using advanced microscopy techniques (optical, SEM/EDXS, FEG-SEM, Raman microspectroscopy etc.) will enable the insights into the incorporation mechanisms of trace elements into crystal phases of dolomites. The results of trace element analysis will be further analysed by descriptive and multivariate statistical methods (PCA, cluster and factor analysis). Detected statistical populations will be compared to microstructural results, in order to recognize any potential multiphase events. Lithogeochemical models and a geological model of pore fluid evolution will be proposed and placed into regional geodynamic context of the area. Dolomites will be classified according to their age and composition, thus providing the first chemostratification of Slovenian dolomites. The research concept is trans-disciplinary, joining research approaches from geology, chemistry, and material science. The project will have strong impact beyond its basic scientific field (geology). Namely, experimental proof of concept of Mg extraction from domestic dolomites will be demonstrated in laboratory (TRL level 3). Slovenian dolomites will be further valorised for their potential Mg extraction. We will identify future funding sources to further increase TLR levels towards 5 after the end of the project. The team believes the proposed project has a potential for high socio-economic impact even after the completion of the project.