Organic matter inclusions in sphalerite and marcasite from the Silesia-Cracow lead-zinc deposits, Poland

The origin and maturation of organic matter (OM) associated with metal sulphides is deduced using biomarkers. Terrestrial biomarkers prevail over admixtures from other sources. Hopane hydrocarbons are important constituents of the OM, indicating a significant contribution from prokaryotes. n-Alkane and hopane hydrocarbon distribution differ significantly between marcasite and sphalerite from the same locality. Hopane isomerization is used to assess the thermal history of Silesia-Cracow lead-zinc deposits. In the Olkusz-Klucze area, the maturation of organic matter is lower (corresponding to a vitrinite refelectance R_O < 0.4 %) in comparison with higher in the Chrzanów and Bytom area (equivalent to R_O ∼ 0.6 %).