Минералогия (Dec 2018)
FAHLORES OF ORE FACIES OF THE YUBILEYNOE MASSIVE SULFIDE DEPOSIT (SOUTH URALS)
Abstract
The Ag-, Te-, Mn, Pb-bearing tennantite and minerals of the tennantite-tetrahedrite series are recognized in chalcopyrite-pyrite-sphalerite-talc-calcite smoker chimneys, bornite- and chalcopyrite-rich and quartz-carbonate-hematite diagenites and siliceous siltstones. Tennantite is а dominant mineral in chalcopyrite crustification of chimneys, while tennantite and tennatite-tetrahedrite are abundant in colloform pyrite replaced by chalcopyrite and in axial conduits filled with sphalerite, talc and calcite. The #Sb value (100Sb/(Sb + As + Te)) (1.4 → 48.5 %) increases and the average contents of Fe (3.8 → 2.1 wt. %), Cu (42.2 → 39.8 wt. %) and As (19.6 → 9.7 wt. %) decrease from central to marginal parts of fahlore grains. It is suggested that the increase in #Sb value is related to the increasing role of seawater in hydrothermal fluids. The average #Fe value (100Fe/(Fe + Zn)) of tennantite decreases in a range from chimneys (42 %) and pyrite-chalcopyrite layers (37 %) to bornite-bearing diagenites (8.5 %). In terms of Fe, Zn and Sb contents, most analyses fall between compositions of fahlores of Cyprus and Uralian types of VMS deposit except of tennantite of bornite-diagenites ores, the composition of which corresponds to that of Kuroko type deposits.
