Geochemical Characteristics, Chronology and the Significance of Laqing Copper Polymetallic Skarn Deposit, Bange County, Tibet
摘要
Laqing deposit located in the south of Bangong Lake-Nujiang suture is a skarn type copper-riched polymetallic deposit.The intrusive rock is well-developed in the mining district,the monzogranite is closely related to mineralization.This paper is based on the data of zircon LA-ICP-MS U-Pb dating.The age of monzogranite is 114.24Ma ±0.87Ma,which imply Laqing deposit was formed in the late Early Cretaceous.The geochemistry results show A/CNK value is near 1.15~1.17 and A/NK value is 1.53 ~1.59.The rock which is ultraluminum type belongs to high-K calc-alkaline series.Laqing rock is enriched in HREE and depleted in LREE,negative Eu is not obvious.In the spider diagram of trace elements,big ion incompatible elements Rb,K,Pb and Ti are rich,and Nb,Ti are poor.The R1-R2 and Rb-(Yb+Nb) diagrams imply the monzogranite formed in the continental crust collision environment.According to regional geology and ore deposit geology data,it is considered that the deposit formed in the background of the Gangdese and the Qiangtang continental crust collision.