The origin of the ore-bearing solution in the PbZn veins of the western Harz, Germany, as deduced from rare-earth element and isotope distributions in calcites

Rare-earth element (REE) and stable-isotope distribution patterns in calcites from the mining areas of St. Andreasberg, Clausthal and Bad Grund, western Harz, Germany, have been determined. Three types of REE distribution patterns were found: type I is characterized by high amounts of light REE without any Ce and Eu anomalies and relatively homogeneous C- and O-isotopic composition. Type II displays conspicuous Ce and Eu anomalies at lower levels of concentration of the light REE. Type III has very low amounts of REE. Types II and III exhibit a more variable C-isotopic composition than type I. The calcite with type I patterns is assumed to be derived mainly from magmatic waters. A possible source for the magmatic waters seems to be the Brocken—Oker granite. Type-II calcites and the sulfides are probably derived from upheated country rock whereas calcite with type-III pattern mineralized from relatively cold descending solutions. The calcite with type-I pattern turns out to be not in equilibrium with sulfides, although both are in intimate contact, e.g. in banded ores. This non-equilibrium indicates two independent sources for this calcite with type-I pattern and the sulfides.