Crustal Source of Pb and S at the Yubileynoe Porphyry Gold Deposit (Southern Urals, Kazakhstan): High Precision Pb\u2013Pb and \u03b434S Data

A V Chugaev,G A Batalin,O Yu Plotinskaya,B I Gareev,S A Kossova,E O Dubinina,A S Sadasyuk

doi:10.1134/s107570152103003x

Abstract

The Yubileinoe large gold deposit, located at the southern end of the Magnitogorsk megazone, is the only known representative of the Au–porphyry systems in the Southern Urals. It is genetically related to granitoids formed in a suprasubduction setting under mature oceanic island arc environment/setting. The obtained isotope (Pb–Pb and δ34S) data indicate the input of mineral-forming components into the Au–porphyry system of the deposit, mainly from granitoid melts, confirming a common source of ore material and ore-bearing granitoids. The geochemical and isotopic characteristics of granitoids indicate the leading role in their genesis of the crustal source, which is considered Late Precambrian continental crust.

Highlights

Deposits of the porphyry family, which play a leading role in the global production of Cu, Mo, Au, Ag, and Re, are formed in various geodynamic settings: suprasubduction, collisional, and postcollisional (Richards, 2009; Sillitoe, 2010; etc.)
It is believed that metasomatized mantle of the mantle wedge plays a leading role in the input of metals and volatile components into Cu–porphyry systems associated with a suprasubduction setting (Richards, 2011 and references therein)
Despite the similarity of the Pb isotopic ratios of ores and igneous rocks and the small scale of variations, there are distinct differences: the points of ore lead are systematically shifted to the left of the of isotopic composition field of Pb granitoids and form short trends in both diagrams, which, based on their position, can be interpreted as mixing trends

Summary

Introduction

Deposits of the porphyry family, which play a leading role in the global production of Cu, Mo, Au, Ag, and Re, are formed in various geodynamic settings: suprasubduction, collisional, and postcollisional (Richards, 2009; Sillitoe, 2010; etc.). The diversity of geodynamic settings presupposes the involvement in ore-forming processes of sources of material differing in geochemical nature. Their identification and assessment of their role in the genesis of specific porphyrytype deposits is one of the most pressing issues in the developed genetic models (Sillitoe and Hart, 1984; Bouse et al 1999; Shafiei, 2010; Plotinskaya et al, 2017a; Shen et al, 2018; etc.). In collisional settings in which Cu–Mo, Mo, and Au porphyry deposits are formed, continental crust makes a significant contribution, but the participation of a mantle source is not excluded

Methods

Results

Discussion

Conclusion