Identification of an Early–Middle Jurassic oxidized magmatic belt,south Gangdese,Tibet,and geological implications

作     者：Yinqiao Zou Xilian Chen Wenting Huang Jian Zhang Huaying Liang Jifeng xu Ling Chen 

作者机构：Key Laboratory of Mineralogy and MetallogenyGuangzhou Institute of GeochemistryChinese Academy of SciencesCuangzhou 510640China University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Isotope GeochemistryGuangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Guangxi Key Laboratory of Marine Disaster in the Beibu GulfQinzhou UniversityQinzhou 535011China 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2017年第62卷第12期

页      面：888-898页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 081803[工学-地质工程] 07[理学] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：supported by Strategic Priority Research Program of Chinese Academy of Sciences(XDB03010302) the DREAM project of MOST,China(2016YFC0600407) a contribution No.IS-2396 from GIGCAS 

主　　题：The South GangdeseEarly Middle Jurassic igneous rockNeo Tethys subductionWater rich and oxidized magmaPorphyry Cu deposit 

摘      要：The south Gangdese region is the site of subduction of the Neo-Tethys and subsequent continental col- lision. Compared with widespread Cretaceous and Cenozoic magmatism, Early-Middle Jurassic magmatic rocks and related deposits are rarely reported, Our work identified a 〉200 km long felsic rock belt asso- ciated with Cu mineralization in the south Gangdese region. We report here zircon U-Pb ages, zircon Ce4＋/Ce3＋ values, and mineral assemblages of two Cu mineralized intrusions within the belt. A horn- blende granite and a diorite porphyry were emplaced at 177.3Ma and 166.3Ma, respectively. Geological occurrence and magmatic hematite-magnetite-chalcopyrite intergrowths suggest that Cu mineralization formed coeval with Jurassic intrusions. Mineralized intrusions have high zircon Ce4＋/ Ce3＋ and EuN/EuN ratios, and hematite-magnetite intergrowths, suggesting their parent magmas were highly oxidized, Hornblende is common and primary fluid inclusions are found in titanite and apatite, indicating their parent magmas were water-saturated and exsotved volatile phases at early stage of rnag- matic evolution. Those magma characters contribute to the formation of porphyry Cu deposits. Given that majority subduction-related porphyry Cu systems have been eroded following uplift and denudation, the well-preserved Early-Middle Jurassic cu mineralized igneous rocks in south Gangdese are favorable prospecting targets for subduction-related porphyry Cu deposits.