Origin of the Kupferschiefer polymetallic mineralization in Poland

The Kupferschiefer ore series, between the Lower Permian (Rotliegendes) ter restrial redbeds/volcanics and the Upper Permian (Zechstein) marine sequenc e, is developed as dark-grey organic matter-rich and metal sulphide-contain ing deposits (reduced zone) and as red-stained organic matter-depleted and iron oxide-bearing sediments (oxidized zone = Rote Faule). The transition z one from oxidized to reduced rocks occurs both vertically and horizontally. This zone is characterized by sparsely disseminated remnant copper sulphid es within hematite-bearing sediments, replacements of copper sulphides by i ron oxides and covellite, and oxide pseudomorphs after framboidal pyrite. T hese textural features and copper sulphide replacements after pyrite in red uced sediments imply that the main oxide/sulphide mineralization postdated formation of an early-diagenetic pyrite. Hematite-dominated sediments local ly contain enrichments of gold and PGE. The Kupferschiefer mineralization r esulted from upward and laterally flowing fluids which oxidized originally pyritiferous organic matter-rich sediments to form hematitic Rote Faule are as, and which emplaced base and noble metals into reduced sediments. It is argued that long-lived and large-scale lateral fluid flow caused the cross- cutting relationships, expansion of the hematitic alteration front, redistr ibution of noble metals at the outer parts of oxidized areas, and the locat ion of copper orebodies directly above and around oxidized and gold-bearing areas. The Rote Faule may be a guide to favourable areas for both the Cu-A g and new Au-Pt-Pd Kupferschiefer-type deposits.