Principles governing the selection of ore regions for gold deposit search

Abstract

Background. In 2020, the Auditing Chamber of the Russian Federation, based on a representative report by its expert analysts M. Men’ and A. Kaulbars, proposed expanding the search for deposits of a number of metals, including gold. Since the fund of easily discovered gold deposits coming to the surface has been significantly reduced, prospecting of ore regions most promising in terms of gold deposits becomes highly relevant.Aim. In connection with the above task, it seems expedient to outline territories within the currently known gold provinces, where the prerequisites and signs of gold ores could be detected with minimal expenditures for their subsequent verification by drilling.Materials and methods. The study involved calculating the shares of the world’s gold reserves attributable to each type of distinguished deposits located in various rocks. The extensive experience of prospecting work carried out in recent decades and culminated in the discovery of the Muruntau deposit in Uzbekistan, a world leader in the development of gold deposits, and Russian largest and giant deposits – Natalka, Sukholozhskoe, Nezhdaninsky, Degdekansky, Maisky, Oktyabrsky, Pavlik, Kupol, as well as the Bakyrchik deposit in Kazakhstan and others, clearly shows that the most promising and largest deposits are selectively localized in favourable rocks and largescale disjunctive dislocations, or faults. To identify favourable rocks, the distribution of the world’s gold reserves in various rocks was analysed, as well as the distribution of reserves in the areas of the largest deposits in ore-bearing faults as the most favourable fault types containing the most powerful and extended gold ore bodies.Results. A comparison of the shares of reserves has shown that the most promising for prospecting are those rock complexes containing the highest proportions of the world’s gold reserves. The article presents the distribution of shares of the world’s gold reserves for near surface and deep-formed deposits of various types. The main share of the world’s gold reserves in deeply formed deposits is shown to be concentrated in the Phanerozoic strata of sandy-clayey composition and in the interlayers of easily replaceable carbonate and amphibolite shales developed in the Proterozoic quartzite-phyllite rocks. The reserves of near-surface gold-silver and gold-telluride ores are selectively located in the young Mesozoic-Cenozoic volcanic rocks of basalt-andesite composition, accompanied by dikes, subvolcanic stocks and the pipes of explosive breccias with large-scale gold ore bodies confined to them. Thus, the most promising areas for prospecting new deposits are those composed of the mentioned rock complexes and crossed by ore-bearing faults, in the zones of which the main largest ore bodies are concentrated. Conclusion. The conducted study into the distribution of the world’s gold reserves in the deposits of various types, as well as the selective localization of ores in deposits with the main and large scale ore bodies in the zones of ore-bearing faults (and, accordingly, containing the concentration of the main share of reserves in a particular deposit), provides a basis for discovering new deposits of the precious metal with minimal expenditures, thus contributing to increasing the resource base of the Russian Federation.