Model of formation of gold-hematite-barite mineralization of the Prognoznoe deposit, Northeastern Russia

The results of geological-structural, petrographical, and mineralogical-geochemical studies allowed the authors to offer an original model of formation of the Prognoznoe deposit. The relict shallow basin accumulated clasts of the Archean Au-bearing iron formations and metamafic rocks from the uplifted block of the Khivach inlier of the Precambrian basement of the Omolon craton terrane. As a result, the rounded and semirounded material composes a gentle volcanic sequence of the Middle-Upper Devonian Kedon tuff sandstones and gravelites (red-colored member of ferrous volcanosedimentary rocks) with dispersed clastic and supergene gold. Secondary enrichment and redistribution of gold and iron in zones of the quartz-hematite-barite-carbonate veinlets are related to the intrusion of thick Cretaceous dikes and sills. The areas without dikes and sills are free of economic gold-bearing bodies. An extremely low amount of sulfides is typical of this deposit and of the epithermal deposits of the Kedon volcanic belt in the southern part of the Omolon craton terrane.