Geochemical and Geochronological Constraints on the Origin of the Meta-basic Volcanic Rocks in the Tengtiaohe Zone, Southeast Yunnan  

作　　者：QIAN Xin FENG Qinglai WANG Yuejun ZHANG Zhibin 

机构地区：[1]State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China [2]School of Earth Science and Geological Engineering, Sun Yat-sen University, Guangzhou 510275, China [3]Geological Survey of Yunnan Province, Kunming 650011, China

出　　处：《Acta Geologica Sinica(English Edition)》2016年第2期669-683,共15页地质学报（英文版）

基　　金：supported by National Natural Science Foundation of China(Grant No.41172202,No.41190073 and No.41302178);China Geological Survey(Grant No.1212011121256);National Basic Research Program of China(2014CB440901);the Fundamental Research Funds for the Central Universities to SYSU;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences in Wuhan(MSFGPMR201402)

摘　　要：The meta-basic volcanic rocks in the Tengtiaohe Zone yield zircon U–Pb ages of 258.8±2.5 Ma and 259.2±1.8 Ma, respectively which agree with the ages of flood basalts of ELIP and are similar to the basaltic rocks and komatiites from the Song Da Zone in northern Vietnam. The results suggest that the age of meta-basic volcanic rocks is Late Permian, rather than the Early Permian or Early Carboniferous ages as previously inferred. Most meta-basic volcanic rocks are strongly enriched in LREEs relative to HREEs and display trace element patterns similar to the ELIP high-Ti basalts, and are enriched in LILEs with negative Sr anomalies. Their initial 87^Sr/86^Sr ratios range from 0.705974 to 0.706188 and εNd（t） from-0.82 to-2.11. Their magmas were derived from an enriched and deep mantle source without significant crustal contamination. These meta-basic volcanic rocks formed in ELIP. Therefore, the Tengtiaohe Zone is not an ophiolite zone and can link to the Song Da Zone in northern Vietnam.The meta-basic volcanic rocks in the Tengtiaohe Zone yield zircon U–Pb ages of 258.8±2.5 Ma and 259.2±1.8 Ma, respectively which agree with the ages of flood basalts of ELIP and are similar to the basaltic rocks and komatiites from the Song Da Zone in northern Vietnam. The results suggest that the age of meta-basic volcanic rocks is Late Permian, rather than the Early Permian or Early Carboniferous ages as previously inferred. Most meta-basic volcanic rocks are strongly enriched in LREEs relative to HREEs and display trace element patterns similar to the ELIP high-Ti basalts, and are enriched in LILEs with negative Sr anomalies. Their initial 87^Sr/86^Sr ratios range from 0.705974 to 0.706188 and εNd（t） from-0.82 to-2.11. Their magmas were derived from an enriched and deep mantle source without significant crustal contamination. These meta-basic volcanic rocks formed in ELIP. Therefore, the Tengtiaohe Zone is not an ophiolite zone and can link to the Song Da Zone in northern Vietnam.

关 键 词：meta-basic volcanic rocks geochemical characteristics zircon U–Pb dating Emeishan large igneous province Tengtiaohe Zone 

分 类 号：P588.14[天文地球—岩石学] P597[天文地球—地质学]