Geochemical Atlas – Erzgebirge and Vogtland

Silver (Ag) in stream sediments shows a slightly right skewed log distribution, with a maximum of 55 mg/kg and a minimum below the detection limit of 0.005 mg/kg. The arithmetic average is 0.35 mg/kg versus a median of 0.10 mg/kg. The area of highest contents (Ag > 2.5 mg/kg) coincides with the central Freiberg mining district. The Ag > 1 mg/kg zone surrounds the district following the extension of hydrothermal veins historically mined for Ag. Similar concentrations occur in the districts of Annaberg-Buchholz and Marienberg-Wolkenstein of the central Erzgebirge. Lower concentrations of Ag > 0.4 mg/kg cover a large WNW-ESE elongated area crossing the Freiberg mining district and extending eastward up to the Sn occurrence of Sadisdorf. Similar concentrations mark the northwestern Tharandt Volcanic Complex and an area between the Ehrenfriedersdorf mining district and Zschopau. The latter, a zone extending 6 km NNE-SSW, coincides with slightly Sn-bearing Cambro-Ordovician metapelites that crop out with NW dip along flat ridges in the strike of the anomaly. These crests include areas with several collapsed shafts and other remnants of historical mining activity. To the SW, the Sn and W districts of Lauter-Elterlein, Aue-Bärengrund and the BiCoNi deposits of Schneeberg show elevated Ag, as well as some spots along the Gera-Jachymov fault zone. In contrast, the westernmost Erzgebirge and the Vogtland region are dominated by lower Ag concentrations, visible in the granites of Eibenstock, Kirchberg, Bergen and most of the surrounding lower Phanerozoic metasediments. The only important area with Ag > 0.4 mg/kg in this part is the Gottesberg Sn-greisen deposit.