GENESIS AND MINERAL-GEOCHEMICAL ZONING OF THE QUARTZ-VEIN GOLD DEPOSIT CENTRAL (KUZNETSK ALATAU)

Abstract

Link for citation: Voroshilov V.G., Molukpaeva D.K., Timkin T.V., Savinova O.V. Genesis and mineral-geochemical zoning of the quartz-vein gold deposit Central (Kuznetsk Alatau). Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 7-17. In Rus. Relevance. The peculiarity of the Central ore field consists in the fact that gold mineralization is entirely localized within the initially homogeneous granitoid massif, therefore, the identified mineral-geochemical zoning is almost entirely caused by superimposed post-magmatic processes. The ore-metasomatic zoning is extremely contrasting and is fixed by various methods, both traditional and the most modern. This creates a unique opportunity to refine and improve the model of formation of gold mineralization, which is widely manifested in the Altai-Sayan folded region, associated with the formation of granitoid massifs of «variegated composition». The purpose of the research is to study postmagmatic hydrothermal-metasomatic processes and the zoning of their location in the Central gold field (Kuznetsk Alatau); substantiate the genetic model of the formation of gold mineralization in the ore field. Objects: granitoids, metasomatites and ores of the Central ore field (Kuznetsk Alatau). Methods: detailed mineralogical and geochemical mapping, optical and electron microscopy, microprobe analysis, study of the typomorphic properties of minerals. Results. The products of postmagmatic hydrothermal activity mapped by the authors are combined into four formations that replace each other in time and space: 1) albite-amphibole metasomatites; 2) quartz-K-feldspar-biotite metasomatites; 3) epidote-chlorite propylites; 4) beresites with conjugated quartz-gold-sulfide veins. The earliest albite-amphibole metasomatites are confined to the bottom part of the granitoid massif and higher along the section (and from south to north) are replaced first by quartz-K-feldspar-biotite metasomatites, and then by epidote-chlorite propylites. Near-vein beresites are superimposed on all previous metasomatites. At the same time, in the zone of development of albite-amphibole metasomatites, beresites have a quartz-muscovite composition, and ores are represented by low-sulfide quartz veins. From south to north (and from bottom to top), quartz-muscovite beresites are replaced by quartz-carbonate-sericite ones, and the sulfide content of the veins consistently increases up to 50–80 %. A model is proposed for the formation of multi-tiered gold mineralization with the determining ore-controlling role of the Kuznetsk-Altai deep fault.