Metallogenic development of the Krakow terrane suture controlling giant Zn-Pb ore deposits in Poland
published: Dec 1, 1999
ArtNo. ESP136000702012, Price: 19.00 €
Upper Silesian-Cracovian Zn-Pb Ore Deposits rank among the largest in the world. Proved metal reserves were estimated at 40 min metric tons of metal zinc and 5 min tons of lead; half of these resources has been exploited out since XII-th century. Most ideas on the genesis of Zn-Pb ores have been developed here. This paper deals with terrane tectonics interpretation of geological structures of the continent and the significance of discovery of the hydrothermal vents (smokers) in these ore deposits. Europe, west of Tornquist-Teisseyre Fault Zone, is a mosaics of tectono-stratigraphic terranes derived from the northern margin of Gondwana and accreted to the south-western margin of Laurentia and Baltica in Caledonian and Variscan orogenies (R. Unrug et al., Tectonophysics, in print). The Matopolska and Lubliniec-Zawiercie-Wielun terranes accreted to Baltica during the Caledonian orogeny. The south-western margin of Baltica is marked by the Tornquist-Teisseyre Transcurrent fault zone (TTFZ) 2500 km long. The Upper Silesia and Moravia terranes were part of Armorica-Cadomia and deformed by collision with the Bohemian block and with the Matopolska and Lubliniec-Zawiercie-Wielun terranes in the Variscan orogeny. The Wielun-Zawiercie-Rzeszotary terrane suture (Krakow suture) is parallel to TTFZ. It has 415 min years kinetic and metallogenic history. About that time large scale movements along this geofracture in oblique pressure regime has formed Caledonian transpressive orogeny. In Zawiercie, the high angle thrust faults sliced granodiorite intrusion intersecting contact skarn zones in Ordovician marbles and hornfelses in metaturbidites. Skarn consists of andradite, titanite paragenetic with black sphalerite and chalcopyrite ores. Three other stitching intrusions of granodiorite in Mrzyglod, Pilica and Jerzmanowice, distributed in margin of the Matopolska terrane, display zones of rutilization and tourmalinization and numerous gold-bearing quartz veins with scheelite and Ag, Bi-tellurides. Still in Silurian a molassa trough was formed in Krakovides Mts. Continental fanglomerates containing clasts of Lower Palaeozoic sedimentary sequence rocks overlie the synorogenic sedimentary sequence. The fanglomerates are ca. 15 m thick in the Zwiercie (bore-hole RK-1 4 879,0-893,4 m) and increase in thickness southward in a molassa through which developed along Krakow suture bore holes Grabowa, Klucze (Alpine-type molassa), Batowice near Krakow, and others. Silurian fossil fish have been found in molassa in bore hole Klucze K-1 1995 m and indicate that joining of the Rheic ocean might be rifted here.