The Kis-Kuel Fe-Cu-Au ± (Ag, Mo, Bi) Deposit, Eastern Yakutia (Russia) — A Link between Iron Oxide Copper-Gold and Intrusion Related Gold Systems

Abstract

The iron oxide copper-gold (IOCG) deposit class includes a number of loosely related deposits with a pool of common characteristics. The Kis-Kuel intrusion-related IOCG deposit in Eastern Yakutia (Russia) with a wide range of mineral styles has a direct genetic link with a cooling intrusion during its formation. The IOCG and the Kis-Kuel have common features for this style—an abundance of iron oxides and a low presence of sulfides. Magmatic contribution to the Kis-Kuel deposit is significant. Intrusive rocks range from diorite to granodiorite in composition. The rare-earth geochemical system of igneous rocks of the Kis-Kuel intrusion is characterized by behavior close to the CHArge-and-RAdius-Controlled CHARAC-system (26 < Zr/Hf < 46 and 24 < Y/Ho < 34) in which the Н/Ho — Zr/Hf ratios of the pair show a distribution close to chondrite (Zr/Hf — 36.6 and Y/Ho — 27.7). Minor deviations of the Kis-Kuel rocks from CHARAC intervals indicate an unevolved magmatic system. Mineralization was discovered at the top of the small Kis-Kuel pluton and includes several types of ore. Iron oxide copper-gold and Cu-Auporphyry ore are present as breccia in hornfels aureole of intrusive rocks with FeOX — 13.58- 63.24 %; Cu — 0-3.57 %; Au — 12.93-64.48 g/t; Ag — 2.7-830 g/t. Associated with IOCG, quartzhematite- galena veins contain: Ag — 22.4-3680 g/t; Cu — 0.014-0.534 %; Pb — 0.1-81.63 %. Arrays of sheeted auriferous quartz veins with arsenopyrite, native gold and bismuth and Ag-Bi sulphosalts contain: Au — 0.15-4.6 g/t; Ag — 20.6-196 g/t; Cu — 0.048-0.24 %; Pb — 0.3-3.73 %. This paper is devoted to a Kis-Kuel diorite-granodiorite–related deposit in Eastern Yakutia (Russia). It is regarded as an intrusion-related gold deposit (IRGD) with a main IOCG and minor Cu-Au-porphyry component of mineralization.