COMPOSITION AND GENESIS OF RARE-METAL GRANITES AT THE ZABYTOE ORE DEPOSIT, CENTRAL SIKHOTE-ALIN

This paper reports a study of rare-metal granites from the area of the Zabytoe ore deposit and the relations between these granites and the tin and tungsten mineralization. The granites were identified as lithi um- and fluorine-bearing rocks of Late Cretaceous age (73-80 Ma). The history of the granite formation was subdivided into three major stage s. During the plutonic stage, the magma, enriched in rare metals, fluo rine, chlorine, tungsten, and trace elements, crystallized to form two facially different rock types: protolithionite granite, making up the core of the massif, and granite porphyry, occurring at the margins. D uring the stage of autometasomatism, the rocks underwent early greisen ization. During the late stage, metalliferous veins were formed, and l ate greisenization took place. The occurrence of numerous fluid inclus ions in quartz grains from the granites points to the high fluid conte nt of the primary metal-bearing magma The results of the mineralogical , petrographical, geochemical, and Rb-Sr and Sm-Nd isotopic studies in dicated that the granites were derived from a palingenetic magma produ ced by the melting of crustal rocks by mantle magma in the presence of fluids. A genetic relationship was established between these granites and the quartz-wolframite and quartz-cassiterite mineralization of th e deposit.