Geochemical Characteristics and Genesis Discussion with Rock Metallogenic Belt of Geza Island Arc, Yunnan

Geza island arc located in the southwest Sanjiang tectonic igneous rock belts which was a products of Ganzi-Litang oceanic crust diving to Zhongdian Landmasses in late Triassic. Lithogeochemical characteristics shown that the porphyry(porphyrite) and island-arc granite rocks have the same rock series (high-K calc-alkaline) and the same genetic type (I-type granite); these rocks trace elements similar to the granite of island arc,which enriched in Ba, La, Hf, Au,chalcophile elements Cu,Pb, siderophile elements Mo, Ni, and depleted in Rb, Nb, P, Ti. In this region, the similarities of porphyry and local acidic volcanic rocks in the main elements, REE and other trace elements and the composition suggest that they both have the same or similar magmatic source rocks. It is shown that the characteristics of the rock with the island arc granite partial melting of source rock, that may come from the arc type volcano rock or island arc volcano rock cognate magma evolution.