Faculty of Mining, Geology and Petroleum Engineering University of Zagreb
Abstract
In the Gornji Vakuf area, which is built up of Palaeozoic sediments and metarhyolites, the authors investigated 47 ore occurrences by geological and different geochemical methods. They distinguish; (a) alluvial, diluvial and fluvio-glacial placers; (b) epigenetic hydrothermal barite-sideritc-tetrahedrite veins located in the Silurian-Devonian schist complex and Upper Permian, and almost monomineralic barite (± tetrahedri-te) veins, breccias and bodies in the Middle Devonian carbonate complex; (c) post-kinematic monomineralic metamorpho-genic quartz deposits interlaying the schists.
The hydrothermal deposits have common characteristics as follows: location exclusively in Palaeozoic strata, epigenetic character; simple, monotonous paragencsis (barite ± siderite as main nonmetallic minerals and Hg-tetrahedrite as preponderant ore mineral); siderite characterized by high CaO, MgO and low MnO content; all tetrahedrites are Hg, Ag, Au, Hi-bearing; barite with average content of 2.9 wt% of SrS04.
The stable isotope study revealed: 34S= + 15.0‰ in barites, -10.1‰ in tetrahedrites, 18O = -9.6‰ and l3C = -3.7‰ in siderites. The microthermometric measurements gave: Th=+200 ºC. in barites.
The very close similarity of all above mentioned results with those found in the minerals of the Kreševo area deposits, urged the authors to assign also the Gornji Vakuf area deposits to the post-Variscan tectonic event.U području Gornjeg Vakufa koje je izgrađeno od paleozoj-skih sedimenata i metariolita, autori su istražili 47 rudnih pojava geološkim i različitim geokemijskim metodama. Razlikuju: (a) aluvijalne, diluvijalne i fluvioglacijalne zlatonosne nanose: (b) epigenetske, hidrotermalne žice u silursko-devonskim Škri-Ijavcima i u gornjopermskim sedimentima te gotovo monomi-neralne baritne (± tetraedru) žice, breče i nepravilna tijela u srednjodevonskim vapnenjacima; (c) postkinematska meta-morf\u27ogena monomineralna kvarcna ležišta u škriljavcima. Hidrotermalna ležišta imaju niz zajedničkih karakteristika: isključivi smještaj u paleozoiku, epigenetski karakter, jednostavnu, monotonu paragenezu (barit ± siderit kao glavne ne-rudne minerale i Hg-tetraedrit kao dominantan rudni mineral), siderit karakteriziran s visokim CaO, MgO i niskim MnO, svi su tetraedriti s Hg, Au, Ag i Bi, barit sa srednjim 2.9 wt% SrS04. Studij stabilnih izotopa je dao: 34S= + 15.0‰ u baritu, - 10.l‰ u tetraedritu, 18O = -9.6‰ i l3C = -3.7‰ u sideritu. Mikrotermometrijska mjerenja dala su:Th= +200 ºC u baritu. Vrlo bliska sličnost svih gore navedenih parametara s onima nađenim u ležištima Kreševa utjecala je na autore da pripi-šu rudnim ležištima područja Gornjeg Vakufa post-variscijski karakter postanka
