Two Stages in Formation of the Yakhton Tungsten-Polymetallic-Gold Deposit (Southern Tien Shan, Uzbekistan): First Isotopic U–Pb Age Data on Zircon (LA-ICP-MS Method) from Intrusive Rocks of the Yakhton Stock

The paper presents first isotopic U–Pb zircon data (LA-ICP-MS method) on the intrusive rocks from the Yakhton stock, which is spatially and probably genetically related to the Yakhton tungsten skarn (tungsten-polymetallic-gold) deposit. This deposit, together with the other W and Au deposits, is part of the largest Au–W metallogenic belt of Tien Shan. The deposit is represented by zones of hydrothermally-altered skarn with scheelite and sulfides (pyrrhotite, chalcopyrite), and later (overprinting) near- and within-intrusive stockworks of veins and veinlets of late metasomatites (propylitic and phyllic alteration) with scheelite-gold and Ag-polymetallic mineralization. The concordant isotopic zircon U–Pb data obtained (305 ± 2 Ma for the early monzonite-quartz monzonite, 304 ± 2 Ma for the granodiorite of the main phase, and 285.4 ± 1.8 Ma for granite) indicate the intrusion emplacement in the Late Carboniferous-Early Permian. This is similar to the dates of the intrusions at the large Jilau Au–W deposit, which is situated in the same metallogenic zone and comprises, together with the early scheelite skarn, also late metasomatites with intense Au–W mineralization corresponding to a large Au deposit. Such age, geological and metallogenic proximity to the Jilau deposit highlights a potential of discovery of significantly greater, than it is currently known, Au–W mineralization at the Yakhton deposit.