Abstract:

Yinkeng porphyry Mo deposit is located in the east of JiangshanShaoxing suture zone. The veinletdisseminated type of Mo mineralization occurred in the interior of porphyry granite. The orebearing granite was classified as Atype granite with high silica and alkaili content, strong fractionation and medium to weak peraluminous. The REE model appears “V” shape, and the enrichment of LREE is obvious with an obvious negative Eu anomalies. The granite is richer in Rb, Th, K, U, La, Ce, Pb and poorer in Ti, P, Nb, Ta, Zr, Hf. The sulfur originated mainly from magma. The metallogenic fluids comprised water and a small amount of CO2, CH4 and CO2-3, which seemed to be mixed with aqueous magma vapour and meteoric water. Orebearing porphyry has relatively high ISr(0.710910.71477) and low εNd(t)(-7.2-1.8)value, which suggests that the source rock of porphyry possibly originated from EarlyProterozoic bed rock. The mean age of Yinkeng deposit is 110.1±1.5 Ma. Research shows that the magma closely related to mineralization occurred in extensional setting. The source region of magma is the lower crust and may have been contaminated by mantle materials. The magma intrusion happened after the transition of Ancient Tethys to Pacific tectonic domain of South China, in the period of lithospheric territorial expansion.

Key words: porphyry Mo deposit, petrogeochemistry, SrNd isotopes, SHRIMP zircon UPb age, Yinkeng, Zhejiang