Gold-bearing and potentially gold-bearing mineralization in the Black Shale thickness of the Arsikom ore field (North Caucasus)

Abstract

The relevance of the research is determined by the need to create a scientific and methodological basis for the development of new methods for forecasting, searching and evaluating new types of gold-bearing ores in the black shale strata of the North Caucasus. The recently accumulated geological material, combined with the positive results of prospecting in recent years in the North Caucasus, makes it possible, through analysis and generalizations, to approach the development of regional genetic and geological prospecting models of largevolume black shale gold deposits based on modern concepts that take into account the geological, geophysical and mineragenic features of the North Caucasus. Objective. To give a generalized characterization of the identified potentially gold-bearing mineralizations localized in the Black shale rocks of the Lower Jurassic using the example of the Cyclaurian suite within the Arsikom ore field. The need for a comprehensive study of the material composition, geological localization conditions of localization of gold-bearing mineralizations of various mineral and morphological types in black shale strata is determined in connection with the hypothesis of polygenic polychronous ore formation, developed earlier on the example of other regions. Methods. Geological analysis of the results of prospecting operations within the territories of the Arsikom ore field based on modern mineragenic concepts using the results of field geological observations and documentation of indigenous outcrops and mine workings. Result. It has been established that the gold-bearing and potentially gold-bearing mineralizations of the Arsikom ore field are overwhelmingly represented by a quartz-veined and veinlet-disseminated mineral-morphological type of gold mineralization. Quartz-veined and veinlet-disseminated zones, individual quartz-veined and veinlet-disseminated are selectively localized in carbonaceous shales of the Cyclaurian formation. Most of them have almost universally undergone folded and discontinuous deformations together with the host rocks, forming mineralized tectonic zones. At the same time, lithological control of mineralization is noted - during the transition from black shales to volcanogenic rocks of the Cyclaurian formation, quartz veins disappear, and mineralized zones continue as an area of increased fracturing and brecciation, cemented with late carbonates, chlorites, chalcedony, iron hydroxides. It is shown that manifestations of pyrrhotite mineralization of the interspersed type selectively manifested in carbonaceous siltstones of the middle part of the volcanogenic-terrigenous section of the Cyclaurian formation may be of interest as one of the promising types of potentially gold-bearing and platinum-bearing mineralizations.