REE geochemistry and petrogenesis of some granite bodies related to tin-polymetallic deposits in Nanling region,South China

Tin-polymetallic deposits, with a characteristic elemental association of Sn, Cu, Pb, Zn, Au, Ag and sometimes Fe, W and Mo, are widespread in the Nanling region, South China. Like W-Sn-Nb-Ta-Be(REE) deposits, they are commonly associated with acid granites. Therefore, it has long been considered that tin-bearing granitic magma derived from anatexis in the tin-rich belt in the sial crust is the only source of primary tin mineralization, including the tin-polymetallic deposits discussed in this paper. Genetically they are related to the continental crust-reworked (I-type and S-type) granites. Based on geologic and geochemical features and, particularly, REE geochemical features, it is proposed that the granite bodies related to tin-polymetallic deposits in this region are products of the derived acid magma generated by partial melting and fractional crystallization from basaltic-andesitic rocks plus a small amount of sial rocks in the lower crust.