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CHEMICAL AND GEOCHEMICAL CHARACTERISTICS OF THE ČEMERNICA ANTIMONITE DEPOSIT IN THE MID-BOSNIAN SCHIST MOUNTAINS
Ivan Jurković
Mehmed Ramović
Franjo Zec
Sažetak
The Čemernica Sb-Zn-Hg-W quartz vein system is situated in Lower Palaeozoic metasediments formed under 3-5 kbars and 350° to 450 °C, intruded by Upper Palaeozoic rhyolites. K-Ar dating indicated three metamorphic phases. The first, 343 Ma old affected phyllite rocks, the second 120-90 Ma metamorphosed rhyolites and the third one, 46 to 37 Ma caused formation of ottrelite schist, host rocks of ore deposit. The Čemernica vein (NW-SE), 1,5 km long, and over 350 m deep, on average 0,67 m thick, is faulted in four separated parts:
»Southern vein«: »Erbstollcn vein«; »Main vein* and »NW-vein«. Structures of the veins are massive, banded, rarely brecciated. Par-agenesis: quartz I (50-95% of ore mass) as the main gangue mineral; antimonite I, II, sphalerite I, II. cinnabar as the main ore minerals; subordinate are chalcedony, siderite, ferberite, jamesonite.berthierite, boulangerile, plagionite, arsenopyrite, scarce arc pyrite I, II, marcasite, pyrrhotite, barite, chalcopyrite I, II, tetrahedrite and enargite, whereas accessories are galena, quartz II, realgar, gold and mineral »X«.
Chemical analysis of 177 ore samples taken from old Saxon and Austrian mining works gave 4.33% Zn, 2,22% Sb and 137 gr/t Ag. Fifteen samples gave trace to 0.1% Hg and eight samples trace to 0.l gr/t Au. Untouched part ol the »Main vein« gave5.9(1% Zn, 8.93%Sb and 126 g/t Ag. Remnant ore gave 2.60-3.28% Zn, 0.69-0.73% Sb and 161 to 190 gr/t Ag. Entire proved, probable and posssible ore reserves (306.000 t) have 5.9% Zn, 4.0% Sb and 114 gr/t Ag.
The 34 S of antimonite is +2.6 ‰ and of sphalerite +3.7‰ indi¬cating juvenile origin of sulphur, Fluid inclusion study of quartz iden-tified three types of fluids: Variscan NaCI-KCI-H2O type related to the Late Palaeozoic granite (rhyolite) megmatism, post-Variscan NaCl-CaCl2 + MgCl2)-H2O type formed by admixing of hot saline connate waters originated from the Late Permian evaporite complex and meta-morphogenic aqueous-curbonic fluids which overprinted ore deposit with CO2, CH4 and N2 components in Late Tertiary.
Ključne riječi
Bosnian Schist Mts; Čemernica; Sb-Zn-Hg-W quartz veins; tectonic setting; morphology; paragenesis; chemical and iso-topic compositions; fluid inclusion study; genesis
Hrčak ID:
13428
URI
Datum izdavanja:
4.12.1999.
Posjeta: 2.668 *