The Unstructured Organic Matter and its Relation to Serpentinization and Gold Mineralization in the Zloty Stok Au-As Skarn Deposit (SW Poland)

Magnetite-rich calcite-dolomite marbles have the highest total organic carbon (TOC) content of the rocks studied from the Zloty Stok gold deposit in SW Poland. There are positive correlations between organic matter and Fe2O3 and MgO contents, suggesting remobilization of organic matter by hydrothermal fluids realeased during serpentinization. Organic matter consists of solid bitumen, with a minor extractable fraction composed mainly of low molecular weight aromatics. The organic matter and carbonate samples have very variable delta C-13 values. Most probably these are the result of isotopic re-equilibration between isotopic phases under high temperatures. Oxygen isotope values of carbonates also exhibit a wide range, caused by variable fluid rock interaction, different oxygen isotopic compositions of the fluids and deposition of carbonates under a range of temperatures.