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Ksenia Mochnacka, Teresa Oberc-Dziedzic, Wojciech Mayer, Adam Pieczka and Michał Góralski

Occurrence of Sulphides in Sowia Dolina Near Karpacz (SW Poland) - An Example of ore Mineralization in the Contact Aureole of the Karkonosze Granite

The authors studied the poorly-known, uneconomic sulphide mineralization site in Sowia Dolina near Karpacz. Host rocks are hornfelses of the Velká Úpa schist series, which belongs to the Izera-Kowary Unit. Ore minerals assemblage includes: pyrrhotite, pyrite, chalcopyrite, arsenopyrite, sphalerite, galena and marcasite, accompanied by ilmenite and rutile. The oldest sulphide is high-temperature pyrrhotite crystallized at about 600°C, which is in good agreement with the temperature range of contact metamorphic conditions, revealed by muscovitesillimanite transformation. Low-temperature pyrrhotite and other sulphides formed at about 390°C (arsenopyrite geothermometer) down to 265°C (pyrrhotite geothermometer), whereas fluid inclusions studies of vein quartz demonstrated the temperature range 380-150°C. Mineralization in Sowia Dolina is similar to other ore hydrothermal deposits known from the proximal or distal contact zone of the Karkonosze granite.

Open access

Ksenia Mochnacka, Teresa Oberc-Dziedzic, Wojciech Mayer and Adam Pieczka

Abstract

The Miedzianka mining district has been known for ages as a site of polymetallic ore deposits with copper and, later, uranium as the main commodities. Although recently uneconomic and hardly accessible, the Miedzianka ores attract Earth scientists due to the interesting and still controversial details of their ore structure, mineralogy and origin. Our examination of the ore mineralization from the Miedzianka district was based exclusively on samples collected from old mining dumps located in the vicinity of Miedzianka and Ciechanowice, and on samples from the only available outcrop in Przybkowice. In samples from the Miedzianka field, chalcopyrite, pyrite, galena, bornite, chalcocite, digenite, arsenopyrite, magnetite, sphalerite, tetrahedrite-tennantite, bornite, hematite, martite, pyrrhotite, ilmenite, cassiterite and covellite are hosted in quartz-mica schists and in coarse-grained quartz with chlorite. In the Ciechanowice field, the ore mineralization occurs mainly in strongly chloritized amphibolites occasionally intergrown with quartz and, rarely, with carbonates. Other host-rocks are quartz-chlorite schist and quartzites. Microscopic examination revealed the presence of chalcopyrite, pyrite, sphalerite, galena, tetrahedrite-tennantite, bismuthinite, native Bi, arsenopyrite, löllingite, cassiterite, cobaltite, gersdorffite, chalcocite, cassiterite, bornite, covellite, marcasite and pyrrhotite. Moreover, mawsonite and wittichenite were identified for the first time in the district. In barite veins cross-cutting the greenstones and greenschists in Przybkowice, we found previously-known chalcopyrite, chalcocite and galena. The composition of the hydrothermal fluids is suggested to evolved through a series of consecutive systems characterized, in turn, by Ti-Fe-Sn, Fe- As-S, Fe-Co-As-S, Cu-Zn-S and, finally, Cu-Pb-Sb-As-Bi compositions.