Petrology and ^(40)Ar/^(39)Ar iso-topic ages of blueschists in Gangmar, central Qiangtang, northern Tibet  

作　　者：DENG Xiguang, DING Lin, LIU Xiaohan & ZHOU YongLaboratory of Lithospheric Tectonic Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 

出　　处：《Chinese Science Bulletin》2001年第5期423-427,共5页

基　　金：the National Key Basic Research Project (Grant No. G1998040800) ; the CAS's Key Basic Research Project for the Tibetan Plateau (Grant Nos. KZ951-A1-204 and KZ95T-06).

摘　　要：The petrology and mineral assemblages of blueschists in the Gangmar, central Qiangtang, northern Tibet were examined, which indicates that the metamorphic condition is high-pressure low-temperature. In this note, we reported the 40Ar/39Ar dating results of glaucophane from two blueschist samples. Their apparent ages are (275.0±1.3) Ma and (287.6±2.3) Ma and similar isochron ages are (275.0±0.9) Ma and (282.4±0.8) Ma, respectively. These iso-topic datings show the high-pressure metamorphism occurring in Lower Permian. The ages also coincide with the evolution of Palaeo-Tethys ocean in Late Palaeozoic.The petrology and mineral assemblages of blueschists in the Gangmar, central Qiangtang, northern Tibet were examined, which indicates that the metamorphic condition is high-pressure low-temperature. In this note, we reported the 40Ar/39Ar dating results of glaucophane from two blueschist samples. Their apparent ages are (275.0±1.3) Ma and (287.6±2.3) Ma and similar isochron ages are (275.0±0.9) Ma and (282.4±0.8) Ma, respectively. These iso-topic datings show the high-pressure metamorphism occurring in Lower Permian. The ages also coincide with the evolution of Palaeo-Tethy s ocean in Late Palaeozoic.

关 键 词：GLAUCOPHANE BLUESCHIST 39Ar/40Ar age Palaeo-Tethys Gangmar northern Tibet. 

分 类 号：P595[天文地球—地球化学]