Tin/tungsten-bearing granites in South China and their metallogenetic relations

Abstract

Tin/tungsten-bearing granites in South China mostly belong to the transformation series, formed by multi-cyclic and multi-staged granitization, partial melting and remelting of materials of the continental crust. They are usually rich in silica and alkalis, poor in Fe, Ti, Ca, Mg, and alumino­ supersaturated. In trace element geochemistry they are rich in Sn, W, Be, Nb, Ta, F, Li, Rb, Cs, and poor in Sr andBa. The initial Srratios are usually more than 0.710. The oxygen isotope composition is usually l\180>10.0%. Sn/W mineralizations began in the Pre-Cambrian and reached their Peak during the Yanshanian (Cretaceous) period. South China is a geochemically anomalous region of Sn and W. The middle to late Proterozoic and lower Paleozoic volcano-sedimentary sequences comprising the crustal basement of this region, are rich in Sn and W, forming important metal source beds. Multi-cyclic tectonic movements and magmatic activities.have resulted in higher degree of maturation of South China's continental crust and higher degree of differentiation, readjustment and mobilization of metal elements, and finally,leading to ex­ tensive formation of Sn/W-bearing granites and Sn/W deposits in the Yanshanian period.