The Formation Mechanism and Mineralization Pattern of Ore-bearing Granite-porphyry in Narigongma

We study the geochemical characteristic of the ore-bearing porphyry body in Narigongma and analyze its formation mechanism as well as the mineralization pattern.The results indicate that,Narigongma ore-bearing porphyry body and Tibet Yulong ore-bearing porphyry body belong to the same mineralization belt and is result of the first episode (40-35 Ma) of the Himalayan movement.The main part of porphyry body is the biotite adamellite porphyries,with a small amount of granodiorite-porphyry and the surrounding rock being the Permian Gadikao group (P2gd) basalt.The ore-bearing porphyry is the composite rock body formed from the comagma undergoing a long-term evolution and a multi-stage emplacement,discontinuously distributing in a moniliform pattern along the regional fault.The ore body mainly appears in the contact zone between inside and outside of the porphyry and in various fractures.The Narigongma ore deposit is the porphyry type of copper molybdenum ore deposit.It has a typical porphyry ore deposit and the hydrothermal alteration characteristic.After the rock mass invasion,as a result of the thermogravimetry strength diffusion,the difference in chemical property between Cu and Mo causes the ore-forming elements to have a spatial zonation,characterized by that the bottom is rich in molybdenum and the upper is rich in copper.