摘要
This paper discusses which period the quartz porphyry in the Dongzhongla Pb-Zn ore district belongs.Through the detailed geological mapping and using the high precision magmatic zircon LA-ICPMS U-Pb dating,the authors date the quartz porphyry from the Dongzhongla deposit.The dated 22 zircon grains from the quartz porphyry present that 206Pb/238U weighted mean age is 126.1±1.1 Ma(n=22,MSWD=0.96).Thus,it denies the previous understanding that these rock units belong to the Linzizong Group Pana formation in Eocene.The crystallization of the quartz porphyry occurred between 125.8~128.0 Ma during the late Yanshanian period.This is in accordance with the age of quartz porphyry from Yaguila which located in the east of Dongzhongla.It indicates that there existed large-scale magma activity before 126 Ma in Nyanqentanglha region.