The Upper Myaundzha Ore Cluster: a Porphyry-Epithermal System in the Central Segment of the Yana–Kolyma Orogenic Belt

Mo–Cu and Au–Ag–Pb–Zn ore occurrences of the Upper-Myaundzha ore cluster, located among Jurassic terrigenous complexes of Inyali–Debin turbidite terrane of the Yana–Kolyma Orogenic Belt have been studied. The Speshnoe Mo–Cu occurrence is a quartz-sulfide stockwork, hosted by porphyry quartz syenite with U–Pb age of 84 Ma. The Spyashchee Au–Ag–Pb–Zn ore occurrence represents a series of carbonate-quartz veins and mineralized zones in Jurassic sedimentary rocks. The geochemical spectrum of stockwork mineralization is Mo–Au–Ag–Co–Cu–(As, W); that of vein-veinlet mineralization is Pb–Ag–Sb–Au–As–Zn–Bi. The Upper Myaundzha ore cluster, located in the central segment of the Yana–Kolyma orogenic belt, is a porphyry-epithermal system, including hypabyssal syenite-monzonite stock, Mo–Cu sulfide-quartz stockwork, and subepithermal Au–Ag–Pb–Zn veinlets. The age of the system coincides with the formation age of the secondary stage of the Okhotsk–Chukotka volcanic belt.