COPPER-SILVER-GOLD KUPFERSCHIEFER DEPOSITS IN EUROPE - LARGE SCALE MINING WITH A FUTURE IN GERMANY
The age of the mineralization of the middle European copper belt is 150 to 250 Ma., post-Variscan, is epigenetic in nature and crosscuts the lower Zechstein geology.
New mineralogical research has discovered a rich, previously unknown, Cu-Se-Pb-Au-Ag-Bi-As-Ba mineralization that heralds a paradigm change in the evaluation of the economic potential of this type of deposit. This establishes the hydrothermal-epigenetic nature of the deposits of the copper belt from Rudna in Poland to Ronshausen in the West of Germany.
In the East German Spremberg-Graustein deposit the mineral association occurs in the border area of sulphide copper mineralization and oxide hematitic Rote Fäule facies intersecting the geology in the form of a wedge at a shallow angle. It causes a characteristic mineralogical-geochemical lateral zoning of the tabular deposit – 3 x 15 km large - with several consecutive seams of oxide and sulphide mineralizations. The newly determined principle selenide minerals are: Clausthalite (PbSe) and Klockmannite (CuSe) and subordinate Eucairite (AgCuSe). Furthermore a significant occurrence of Electrum (AuAg), native Gold (Au), native Silver (Ag), Naumannite (Ag2Se), Eucairite (AgCuSe), Schapbachite (AgBiS2), and Barite (BaSO4) belongs to the assemblage. In the investigated deposit Spremberg-Graustein this assemblage is abundant.
Previously, the occurrence of the Kupferschiefer mineralization was considered to be only local and dominantly diagenetic. The new and significant recognition of the regional hydrothermal nature of the mineralization, combined with Rote Fäule alteration and large scale rift tectonics, leads to new parameters available for the exploration of more world class copper-silver-gold deposits. These parameters make it possible to outline exploration targets of hundreds of millions of tons of copper-silver-gold ore and to pursue science based strategies that will lead to more discoveries.