Spatial and genetic relationship of endogenous and exogenous gold content in the area of the Pervomaisko-Zverevsky ore cluster (Middle Urals)

Abstract

Te relevance of the work is due to the need to improve the efciency of appraisal work on new and unconventional types of gold mineralization within the known ore-placer regions and clusters. Te purpose of the work is to show the results of the study of the spatial and genetic relationship between endogenous and exogenous gold content using the example of the Pervomaisk-Zverevsky ore-placer cluster (OPC). Research methodology. Mineralogical and geochemical sampling of ore bodies outcrops, chemical weathering crusts; schlicho-mineralogical studies; study of native gold on a digital basis, taking into account the shape, size and composition of particles; mapping of parameters of gold particles in the section of the crust, the upper horizon of the Mesozoic eluvium. Results. Te factors that determine the localization of gold content within the OPC are substantiated. Among the endogenous factors: structural-tectonic, magmatic, metallogenic specialization of individual blocks. In the volume of the Verkhotursky granodiorite massif (an object of prospecting), a linear substockwork with a low level of mineralization of the gold-polysulfde-quartz type was revealed. When considering exogenous factors, the confnement of ore-bearing chemical weathering crusts to smoothed relief areas, comparable with Mesozoic denudation leveling surfaces and containing dispersed gold mineralization in the basement, was established. Te profle of the weathering crust in the Verkhotursk area is complex, without a distinct vertical hypergene zonality. Tese crusts are considered as “superimposed”, fnally formed under the infuence of later low-temperature argillization processes. Te most signifcant concentrations of gold are established in the upper horizon of the crust - the zone of the Mesozoic eluvium. Based on the mineralogical and geochemical study of metal particles, a model of its accumulation, sufusion-gravity, is proposed. Under certain conditions, a gold-enriched crustal horizon can have an independent applied value. In past years, gold-bearing areal accumulations (poddernikovye placers) were successfully mined. When mapping free gold, a wide range of sample fuctuations (from low- to high-grade) was established, indicating in favor of the multi-stage processes of ore formation in the OPC area. Conclusions. Many years of experience in the geological-geomorphological, mineralogical-geochemical study of the OPC of the Ural region has been tested by the practice of forecasting and prospecting. Te approaches outlined, taking into account the close spatial relationship between endogenous and exogenous gold content, are recommended for implementation and further improvement.