Neoproterozoic magmatism in eastern Himalayan terrane  

作　　者：Yuhua Wang Lingsen Zeng Li-E Gao Chunli Guo Kejun Hou Lifei Zhang Wei Wang Huiyi Sun 

机构地区：[1]Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [2]Key Lab of Submarine Geosciences and Prospecting Techniques, Ministry of Education, and College of Marine Geosciences, Ocean University of China, Qingdao 266100, China [3]Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China [4]Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China [5]Institute of Geology, China Earthquake Administration, Beijing 100029, China [6]Beijing SHRIMP Centre, Chinese Academy of Geological Sciences, Beijing 100037, China

出　　处：《Science Bulletin》2017年第6期415-424,共10页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China (41425010,41273034);the Public Welfare Industry Scientific Special Expenditure (201511022);the China Geological Survey Project (12120115027101,12120114022701)

摘　　要：Geochronological investigation on gneisses of granitic to leucogranitic compositions in Cuona,south Tibet,reveal that their protoliths formed at 808.8 ± 7.9-816.4 ± 3.4 Ma and 855.8 ± 7.0 Ma,respectively.Zircon rims from the granitic gneiss record a metamorphic age of 739.4 ± 4.3 Ma.Lu-Hf isotopic analyses on zircon grains with Neoproterozoic ages yield negative ε_(Hf)(t) values from-9.0 to-4.2,and the corresponding two-stage Hf model ages are 1965-2228 Ma.Whole-rock geochemical data indicate that all granitic gneisses are K-riched calc-alkali series.These new data together with literature data show that(1) the Himalayan terrane experienced an episode of Neoproterozoic magmatism at 850-800 Ma;(2) the Neoproterozoic magma of granitic compositions were derived from partial melting of ancient crusts,possibly due to the thermal perturbation related with the breakup of the Rodinia supercontinent.Geochronological investigation on gneisses of granitic to leucogranitic compositions in Cuona, south Tibet, reveal that their protoliths formed at 808.8 ± 7.9-816.4 ± 3.4 Ma and 855.8 ± 7.0 Ma, respectively. Zircon rims from the granitic gneiss record a metamorphic age of 739.4 ± 4.3 Ma. Lu-Hf isotopic analyses on zircon grains with Neoproterozoic ages yield negative Hf（t） values from -9.0 to -4.2, and the corre- sponding two-stage Hf model ages are 1965-2228 Ma. Whole-rock geochemical data indicate that all granitic gneisses are K-riched calc-alkali series. These new data together with literature data show that （1） the Himalayan terrane experienced an episode of Neoproterozoic magmatism at 850-800 Ma; （2） the Neoproterozoic magma of granitic compositions were derived from partial melting of ancient crusts, possibly due to the thermal perturbation related with the breakup of the Rodinia supercontinent.

关 键 词：FGranitic gneiss Neoproterozoic magmatism Zircon U-Pb dating Eastern Himalaya 

分 类 号：P588.1[天文地球—岩石学]