ЗОЛОТОНОСНОСТЬ КОЛЧЕДАННЫХ РУД КАМЕННООЗЕРСКОЙ СТРУКТУРЫ (ВОСТОЧНАЯ КАРЕЛИЯ)

Abstract

Massive sulfide ores are represented in Kamennoozcrskaya (Stone Lake area) greenstone belt structure by two their types: 1) hydrothcrmal volcanic-sedimentary strata-bound ones, with massive, banded and disseminated fabric, and 2) massive, brccciated, vcinlet-disseminated gold-bearing sulfide-polymctallic ores cross-cutting the rocks of Vozhmozcrskaya series. Strata-bound, weakly metamorphosed ore bodies arc located at several horizons along the contact between Kamennoozcrskaya and Kumbuksinskaya scries within the deep fault zones with the same names. Those ores have pyritc and/or pyrrhotitc-pyritc composition with small amount of chalcopyritc and sphalerite, low grade of base metals and the weakest gold admixtures (not more than 0.06 ppm). In some local areas, where these strata-bound bodies occur close to sulfide Cu-Ni ores in ultrabasic rocks, they contain pen-tlanditc and the higher Co, Ni, Cu, Zn concentrations, with Au grade up to 2-9.2 ppm (Lcbyazhinsky and Svct-loozcrsky areas). Brccciated and rccrystallizcd pyrite ores within Kumbuksinsky fault (Zolotyc Porogi locality) contain up to 0.08-0.4 % Sb and As, and up to 0.6-1 ppm Au. As the prospective gold-bearing objects arc appraised Sevcrovozhminskoye and Vcrkhncvozhminskoye massive suifidc-polymetallic ore occurrences, where ores contain pyritc, chalcopyritc, sphalerite, pyrrhotite, galena, bomitc and chalcositc. Some samples at Sevcrovozhminskoye occurrence have shown gold grade up to 1.2-2.8 ppm, and up to 167 ppm Ag; there was even detected gold grade up to 20 ppm at Vcrkhncvozhminskoye locality. Appraised gold resources of Sevcrovozhminskoye occurrence make about 600 kg.