Die Blei-Zinkerzlagerstätten des Pflerschtals

The stratabound lead zinc ore deposits of the Pflersch Valley (Eastern Alps) are intercalated in pre-Triassic folded and metamorphosed pelitic sediments of the ötztal-Stubaier Masse. The ores (sphalerite, galena, pyrrhotite etc.) are stratigraphically controled by graphitic shists and tuffitic layers. The thickness of the ore bodies varies between some centimeters to some meters. As part of the regional setting these orebearing strata were metamorphosed during several metamorphic episodes together with these metasediments. Field observations, supplimented by microscopic studies, and the calculation of p-T-conditions indicate that now partly mobilized ores probably had their origin during the last pre-Triassic metamorphic events. These ores probably came in part as sulfide melts. There seems also a possibility of an additional alpine ore mobilization process. On the basis of age determinations and petrographic studies carried out in the ötztal-Stubaier Masse by other authors it is possible to say that the ore-bearing former sediments belong to Silurian or even pre-Silurian age (>410my).