Organic-Inorganic Interactions in Kupferschiefer – How did organic matter control mineralization?

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Organic matter (OM) is frequently associated with ore deposits, but is largely not considered as a co-genetic factor. Thus, new fundamental insights are required to elucidate the role of organic-inorganic interactions during the formation of ore deposits. It is the aim of this proposal to examine the impact of OM on the ore forming process in the “Kupferschiefer system”, which offers the potential to act as “analogue” also for a wider picture of stratiform base metal sulphide deposits using a multi-proxy approach based on cutting-edge analytical technologies. The “Kupferschiefer system” was economically important since the Middle Age. Today mining still exists in Poland whereas activities in Germany are mainly ceased. However, there are considerations about mining the Spremberg deposit (Brandenburg, Saxony) and currently drilling activities in Thuringia are in place again. A specific feature of the Kupferschiefer system in Germany and Poland is that it was largely not overprinted by elevated thermal stress, thus allowing organic geochemical and imaging analyses of the OM. It is this low thermal maturity (mainly early oil window) in southern Brandenburg, Saxony Anhalt and northwestern Bavaria which makes the Kupferschiefer a suitable natural laboratory and -via extrapolation- a potential analogue even for older systems with higher thermal maturities, for which the exploration, evaluation and exploitation efforts can be improved. The proposed multi-proxy approach will fill a fundamental gap in studies that largely lack microscale-resolved analyses of organic-inorganic interactions. The project concept combines standardized organic geochemical (e.g., GC-MS) and imaging techniques (organic petrography, SEM, TEM) with up-to-date advanced methods like Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) for the elucidation of organic NSO compounds for ore formation processes. Further new methodologies will be applied such as scanning transmission X-ray microscopy (STXM) and molecular imaging mass spectrometry (MALDI-MSI), that enable the characterization of organic bonding types and spatial molecular occurrence.