Genesis and ore-bearins structures of the Chuchukur noble metals deposit of the North Caucasus

Abstract

Relevance. The Largest Chuchkur deposit in the Caucasus in the Northern Elbrus region was originally explored as a gold ore object. Additional sampling in the ore zone showed the constant presence of platinum group metals commensurate with its gold content, which allowed us to consider it as a complex (Au, Pt, Pd) noble metal. The purpose of this work: is to identify ore-bearing structures and establish the Genesis of the Chuchkur gold ore deposit. Research methods: mapping the ore load of the Northern Elbrus region at a scale of 1:25000, geological survey of the site at a scale of 1: 5000, geochemical survey and study of the ore body at a scale of 1: 2000. The ore body was studied by mineralogical mapping, mineralogical and petrographic methods. Result of work. Favorable high-altitude terrain allowed us to consider the full section of the ore structure and evaluate the genetic features of the Deposit. Metasomatic ore bodies of beresite-propylites are localized in the volcanogenic-sedimentary strata of tuffs and tuffites of the Kinyrchad suite (P1kn) of the root zone of the Permian volcano. Fluid-active ore channels break through the ore-bearing tuff strata of the lower Permian and the underlying dislocated black shales. In the underlying Devonian (D2ar) black-shale strata vein-sectioning bodies of metasomatites and beresites are developed along subvolcanic granodiorites. Activation and removal of precious metals from Devonian black shales with their deposition in Permian tuffites is assumed. The direct connection of ore metasomatism with the Permian andesite-dacite volcano allows us to define ore genesis as large-scale propylitization of acidic rocks with ore metasomatites and two facies of beresitization (beresites and beresitpropylites). Conclusion: Functionally ore-bearing black shales of the Devonian of the Chuchkur deposit are clearly manifested in two ways: on the one hand, they are ore-bearing terrigenous concentrators of noble metals (Au, Pt, Pd) with areal sub-industrial anomalies of these metals; on the other hand, they are ore-forming, performing donor functions and being a source of gold and platinoids in the Chuchkur deposit. Ore concentrations of metals in the Chuchkur deposit are formed by the hydrothermal fluid active zone of the Permian paleovolcano with the mobilization of metals from the ore-bearing Devonian black shale stratum. The noble metals of the black shales of the Devonian are mobilized and redeposited stratum in superposition areas of magmatic bodies and fluid-active deposits with the formation of industrial ore bodies.