Geochemistry and Origin of the Cassiterite from Rędziny, Lower Silesia, Poland

Abstract

Abstract.Thegeochemistryofcassiteritemayindicateitsorigin.IncassiteritefromRedziny,FeandTiare major substitutes for tin, whereas Nb, Ta and Mn do not occur in significant amounts. Tungsten, whichconcentratesonlyinsomecassiteritedomainsinamountsthatmayexceed1wt.%,iscommonlyclosetozero.ThedistributionofTi,anelementmobileunderstronglyreducingconditions,indicatesthattheformationofthe oldest cassiterite preceded a sphalerite-chalcopyrite-ferrokesterite paragenesis, and that the latter wasfollowedbycassiteritecoevalwitharsenopyrite.Bothcassiteritesprecipitatedunderconditionsofverylowoxygen fugacity, probably below log f (O) 2 = –40. The younger cassiterite, present in oxidized assemblages,crystallized under increasing f (O) 2 .Theco-variationsFe+Mn vs .Nb+TaandHf vs . Zr clearly and une-quivocally point to a hydrothermal origin for the cassiterite from Redziny that can be linked topost-magmatic activity developed around the Karkonosze granite intrusion. Key-words : cassiterite, quartz veins, Redziny, Lower Silesia, Poland, geochemistry, origin