WANG Xin-song1,2, BI Xian-wu1, LENG Cheng-biao1, TANG Yong-yong1,2, LAN Jiang-bo1, QI You-qiang1, SHEN Neng-ping1
（1. State key Laboratory of Ore Deposits Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550005, China;
2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China)
Abstract: Hongshan Cu-polymetallic deposite, which has long been considered as an Indosinian skarn-type Cu-polymetallic deposit, is located in Zhongdian arc, south of Yidun arc, northwest Yunnan, China. Recent researches show that there is late Yanshan Epoch porphyry Cu-Mo mineralization in Hongshan deposit area too. In this paper, late Yanshan Epoch granite porphyry in Hongshan deposit area was found for the first time. LA-ICP-MS zircon U-Pb dating of the granite porphyry yields crystallization age of 81.1±0.5 Ma, which is very close to a previously reported molybdenite Re-Os isochron age of porphyry Cu-Mo mineralization (77±2Ma). It means that there is a consistent spatial-temporal relationship between the granite porphyry and the porphyry Cu-Mo mineralization. The age of the late Yanshan Epoch magmatism(81.1±0.5 Ma) in the Hongshan Cu-polymetallic deposit is consistent with the peak period(around 80Ma) of the granites magmatism under post-orogenic extensional environment in Yidun arc. So it is suggested that there is not only Indosinian skarn-type Cu-polymetallic mineralization in Hongshan area, which is closely related to the subduction of oceanic crust, but also the late Yanshan Epoch porphyry Cu-Mo mineralization under post-orogenic extensional environment.
Key words: zircon; LA-ICP-MS; U-Pb dating; granite porphyry; Hongshan Cu-polymetallic deposit; Zhongdian, Yunnan
E-mail: gyigxsw@hotmail.com
ACTA MINERALOGICA SINICA Vol. 31, No. 3, 2011, Page 315-321
