Литосфера (Apr 2018)
The prospects of gold mineralization of the Precambrian complexes of the Subpolar Urals
Abstract
Precambrian strata - the most important source of many types of mineral raw materials. Within their boundaries are the largest deposits of iron, gold, chromium, diamonds, platinoids, nickel, copper, polymetals, vanadium and uranium. Consequently, they can be considered as the most promising provinces for the discovery of new large deposits. The authors briefly described the gold mineralization of the Urals, which are distributed unevenly and mainly among Paleozoic formations. It is noted that common features to all these objects is their location to the east of the Main Ural Foult (GUR - in Russian), and in the North, Subpolar and PolarUrals Mountains, west of the GUR, on the Precambrian development area of the Central Ural Uplift, manifestations of indigenous gold are still rare. The authors cite the results of geological exploration for ore gold within the Khobeiz “dome”, at a very promising Halmerinsky ore-placer site, where the Sosnovoye, Talayiz and Vorgavozh deposits were discovered. These deposits are confined to the Omras'shorian fault system, which is traced more than 25 km along a strike across the whole area, and the width of the development of individual structures is 4 km. At the Sosnovoe deposit, ore bodies are located within a block about 140 m wide and 240-250 m long, bounded by the West and East faults of the north-eastern strike, steeply falling to the west, and the shallow zones of melanocratic blastomylonites. Inside this block the ore bodies are confined to systems of synthetic cracks of the cleavage of the northeastern orientation, made with quartz with pyrite impregnation.The Talayz deposit is a gently sloping mineralized zone (on average 30 m thick) in the horizon of melanocratic schists, beneath a screen of metavolcanics of acidic composition. Gold-bearing ones are: quartz-carbonate veins, lenses, veins, with extremely uneven distribution of sulphides and attached to zalband parts of quartz veins with the development of vein-disseminated sulfide mineralization. The position of the ore-bearing zones of the Vorgavozh deposit is determined by the confinement to blastomylonites along the contact with the overlapping horizon of metavolcanics of acidic composition complicated by a series of northeastern tectonic disturbances. Ore-bearing zones (thickness 2-18 m) are represented by chlorite-muscovite-albite schists containing quartz, quartz-carbonate veins and veins, with various aggregates of pyrite and dissemination of chalcopyrite, and rarely, galena. From the given data the conclusion about high prospects of Precambrian structures of the Subpolar Urals on opening of new deposits of gold is made.
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