INVERSION OF THE SULFUR REGIME IN ORE-BEARING SOLUTION AND ITS ROLE IN THE FORMATION OF GOLD-QUARTZ DEPOSITS: EVIDENCE FROM THE VERKHNYAYA INDIGIRKA REGION, YAKUTIA

Abstract

When studying the crystallization sequence of the ore minerals in some gold-quartz deposits of the Verkhnyaya Indigirka region of Yakutia (Nagornoe, Dvoinoe, Klich, Kontrol'noe, Khangalas, Dirin-Yuryakh, Taryn, Kus-Yuryue, Pil, Malyutka, Zhdannoe, and Sopka Kvartsevaya), we discovered a sulfur regime inversion in hydrothermal solutions and its significant influence on ore precipitation. The inversion is expressed in the successive increase and decrease of μH2S in a hydrothermal solution with a general decrease of temperature and salinity. When μH2S decreases below the equilibrium of bournonite + pyrite = galena + chalcopyrite, gold is precipitated. The studied deposits formed during Mesozoic tectonogenesis related to the collision of the Kolyma-Omolon composite terrane and Northern Asian Craton from the end of Jurassic to the beginning of the Neocomian.