Geochemical Atlas – Erzgebirge and Vogtland

Niobium (Nb) shows a maximum concentration of 21 mg/kg, a minimum of 0.1 mg/kg, an arithmetic average of 1.5 mg/kg and a median of 1.0 mg/kg. The histogram indicates a close to log normal distribution in proximity to the median, whereas higher concentrations of 4 to 7 mg/kg form a secondary maximum related to the granites of Eibenstock and Schellerhau. Core areas with Nb > 6 mg/kg traverse these two massifs in a NWSE strike. Areas with Nb > 4 mg/kg match their outer limits and additionally form a 5 km zone in the NE part of the Kirchberg granite. Also the Markersbach granite in the easternmost part of the study area shows slightly elevated Nb. Further, areas with Devonian sedimentary and volcanic rocks northwest of Oelsnitz (western Erzgebirge), the metapelites of the Lössnitz-Zwönitz Syncline and small spots within the Bergen granite are characterized with Nb > 2 mg/kg. In contrast, the central part of the Erzgebirge and vast parts of the gneiss dominated areas of the eastern Erzgebirge are characterized by diffuse distribution of slightly elevated Nb (0.5 – 1.0 mg/kg). The same area is coenriched in Rb and Ti. Lowermost concentrations of Nb < 0.6 mg/kg occur predominantly in the phyllite rich northern Erzgebirge rim around Stollberg and in a triangle of mainly Ordovician metasediments between the Fichtelgebirge granite to the south, the Eibenstock granite to the east, and the town of Oelsnitz to the west. Nb generally correlates with elements showing affinity to acid magmatites such as Sn, W and Cs.