Geochemical Atlas – Erzgebirge and Vogtland

Bismuth (Bi) shows a right skewed log distribution with a strong contrast between the arithmetic average of 2.4 mg/kg and the median value of 0.4 mg/kg. The lowest concentration is 0.04 mg/kg, the highest 494 mg/kg, which are influenced by mining activities. Granitoid intrusions coincide with elevated Bi, showing an arithmetic average close to six times higher than that of the gneisses. Areas with Bi > 10 mg/kg are bound to former U and Sn mining sites in and around the Eibenstock granite (Gottesberg, Johanngeorgenstadt, Schneeberg) and to the eastern Altenberg-Teplice caldera. Larger areas with Bi > 1 mg/kg coincide with the Sn and base metal mining sites of the eastern Erzgebirge and with the Freiberg district forming a 40 km WNWSE trending arc. In the central Erzgebirge, they occur in the districts of Annaberg-Buchholz, Ehrenfriedersdorf, Marienberg-Wolkenstein and Pobershau, which are related to granite cupolas of the underlying Central Erzgebirge Pluton. In the western Erzgebirge they coincide with the granites of Kirchberg, Bergen, Eibenstock including eastadjacent metasediments, and with the concealed Eichigt granite. Bi shows a clear relationship to Sn-, U- and Pb-Ag deposits on the one hand and to concealed granite cupolas on the other hand. Thus, low grade Bi anomalies (Bi > 0.6 mg/kg) without known mining activities may indicate concealed granites or undiscovered mineralisation of the above metals. Examples are the NNE-striking corridor of the northern Erzgebirge rim around Zschopau and the Czech border region WSW of Altenberg.