Abstract

AbstractThe 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.

Highlights

  • 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

  • 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

  • The hydrothermal, vein-type copper-uranium-polymetallic ore deposit of the Miedzianka district is located in the eastern part of the Karkonosze-Izera Massif (KIM), close to the IntraSudetic Fault (Fig.1; Mazur, Aleksandrowski 2001)

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Summary

Introduction

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. According to Berg (1938 and older references therein), there were four mining fields in operation, namely, the western field close to the Karkonosze granite and the central field (both named collectively as the Miedzianka field), the eastern field in Ciechanowice and the northern field located north of the Bóbr River. The latter field can be identified with the so-called “Lead Mountains” (Góry Ołowiane) which are a part of the Kaczawa Metamorphic Complex. In the copper vein formation, Websky (1853) identified four vein systems of different strikes, all younger than the Karkonosze granite

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