PGM minerals in gold-placer deposits in NIederbayern, Germany

[Marco E. Ciriotti]

Referenza:
▪ Dill, H.G., Klosa, D., Steyer, G. (2021): Schwermineraluntersuchungen an Palladium-, Iridium-und Osmium- Minerale führenden Goldseifen aus Niederbayern, Deutschland. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 158, 1005-1010.

Abstract:
Platinum-Group Minerals/PGM (Iridosmine, unnamed Ir-Os sulfide), porpezite (Cu-Pd-bearing gold), Ag-free gold and goldamalgam from alluvial and fluvial placers in the foreland of the Bayerischer Wald, Germany, have been investigated by means of SEM-EDX. PGMs identified in the heavy mineral concentrate are supposed to have been orginated from (ultra)basic igneous rocks of the Teplá-Barrandiam Zone, part of which is also exposed in the eastern Bayerischer Wald. Cu-bearing propezite may have derived from the denudation of hematized sulfide-free shearzones in the highly regionally metamorphosed parts of the Bayerischer Wald. Unlike the PGM, no definite provenance area can be claimed to have delivered the Pd-bearing gold grains. This is also true for the Ag-free gold, because of the ubiquitousness of potential source rocks in the adjacent crystalline basement. There is no doubt about benefication attempts made in the recent past to amalgamate placer gold upstream of the sampling site on the banks of the River Danube.