Finding and Significances of Chongjiang Porphyry Copper (Molybdenum, Aurum) Deposit,Tibet

The Chongjiang copper deposit is a large porphyry copper (molybdenum, aurum) deposit found in Tibet in recent years. It is also the first one that has made great breakthrough during the process of looking for porphyry copper deposit in Gangdise orogenic belt. The deposit has the characters of circular and surfacing model in mineralization and alteration belt. Cu mineralization is according to K-Si alteration belt approximately. Methods such as ICPMS on the rocks with mineralization, Re-Os dating on molybdenite and U-Pb dating on zircon, were used in this research. The results show that the mineralizing porphyry enriches in K, Na, Al and light rare earth element (LREE) with high LREE/HREE (8.56-23.1). The porphyry is normal in Eu (δEu=1.001), but weak negative abnormal in Ce (δCe=0.84), and shows the characteristics of the transitional granite between type Ⅰ and type A. The characteristics reflect the magmatism related to asthenospheric upwelling. The Chongjiang porphyry copper (molybdenum, aurum) deposit formed in 14-16 Ma, the transitional period of extrusion and extension in orogenic belt.