Origin of the Cracovian-Silesian Zn-Pb deposits

Antoni Wodzicki


Geneza złóż cynku i ołowiu regionu śląsko-krakowskiego

Previous work has shown that most of the mineralization occurs as metasomatic replacement of hydrothermal dolomite, and as cavity-filling in hydrothermal karst breccias. It was emplaced along a paleoaquifer within the Muschelkalk mainly during Early Cimmerian movements. Available geological and geochemical data suggest that the hydrothermal fluids were episodically expelled from the Upper Silesian coal basin as a result of fluid overpressure generated during burial and diagenesis. Initially the fluids were buffered by quartz-illite-K feldspar, and aqueous carbonate-methane equilibria. During hydrothermal karst formation and ore deposition they became more oxidizing and acid, probably as a result of mixing with near surface waters and the generation of hydrogen ions by oxidation of methane. The zinc and lead could not have been transported as chloride or bisulphide complexes, but may have been transported as organometallic complexes.

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