Structure, mineralogy, and Pb isotopic composition of the As-Au-Ag deposit Rotgülden, Eastern Alps (Austria): significance for formation of epigenetic ore deposits within metamorphic domes

The abandoned As–Au–Ag mining district Rotgülden is located within the eastern Tauern window of the Eastern Alps and was reinvestigated in order to evaluate ore deposition during Alpine/late orogenic tectonic processes. Four major ore types have been recognized: (1) quartz-sulfide veins within Variscan basement rocks; (2) deformed metamorphic massive ores within fold hinge zones (“saddle reefs”) of Permian to Mesozoic cover sequences; (3) ores in tension gashes of the cover sequence; and (4) irregular replacement ore bodies in marbles of the cover sequence. Ore deposition was intimately related to late orogenic exhumation by stretching of footwall sequences within the Tauern metamorphic core complex during late Oligocene and Neogene. Hydrothermal systems developed and metals from apparently distinct sources were deposited under decreasing temperature conditions. Lead is distinctly radiogenic and resembles the lead in Au-quartz veins of the Mesozoic cover sequence of the Hohe Tauern. Received: 24 January 1996 / Accepted: 24 July 1997