Geological characteristics and genesis of porphyry copper deposits in Qinzhou-Hangzhou suture zone, South China
钦-杭结合带斑岩型铜矿的基本地质特征及成因分析

The Qinzhou Bay-Hangzhou Bay suture zone (QHSZ) is an important porphyry copper deposits (PCD) belt. PCDs are well distributed in the northern, the middle and the south sections of the QHSZ. They are mainly formed in the Yanshanian Period. Porphyries related to copper mineralization are mainly granodiorite porphyry, granite porphyry and sub-dacite porphyry, which belong to the calc-alkaline magma series of acidic rock. The porphyries above have similar trace element geochemical characteristics of the Neoproterozoic island arc igneous rock. They are derived from the partial melting of a mixture of magma in asthenosphere and the lower crustal material, and are related to the lithospheric mantle affected by earlier plate subduction, with evident crust-mantle contamination. The geodynamic setting of the Yanshanian petrogenesis and metallogenesis of the QHSZ is characterized by subduction of the Pacific plate, while the Yanshanian porphyries and copper ore bodies have the trait of island arc magma system, which is related to the geological evolution before the Mesozoic tectonic transition event in South China. It is concluded that such acidic porphyries of the QHSZ resulted from the partial melting of the Proterozoic island arc basaltic rocks during the Mesozoic, and the associated PCDs have the gene of island arc subduction environment.