Abstract

The ore bodies belong to two separate ore-forming cycles characterized by an upward change from pyrite-chalcopyrite through sphalerite-pyrite ore to Zn-Pb ore rich in barite. Each cycle is characterized by a marked upward increase in S 34 /S 32 ratios in galena, sphalerite, and chalcopyrite, but a narrow spread at each stratigraphic level. The sulfides of Cu, Pb, and Zn are interpreted as products of magmatic hydrothermal springs, deposited syngenetically with their host rocks. The pyrite shows a wide spread in sulfur isotope ratios, and enrichment in S 32 is common; the sulfur of the pyrite is believed to be partly of magmatic (syngenetic) and partly of biogenic (diagenetic) origin. Barite was derived from magmatic hydrothermal barium and sulfate of marine origin.

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