Petrology,Geochemistry,Chronology and Geological Significance of Jiang Tso Ophiolite in Middle Segment of Bangonghu-Nujiang Suture Zone,Tibet
Huang Qiangtai
Li Jianfeng
Xia Bin
Yin Zhengxin
Zheng Hao
Shi Xiaolong
Hu Xichong
Abstract：Jiang Tso ophiolite,which belongs to the most eastern part of Qieli Lake ophiolite subzone,is located at the middle segment of the Bangonghu-Nujiang suture zone to the south of Pung Lake ophiolite.The rock association of Jiang Tso ophiolite is relatively complete and mainly composed of metamorphic peridotite,gabbro and diabase.Comparing with N-MORB,the ma-jor and trace elements of Jiang Tso ophiolite are characterized with high content in Mg and low contents in Ti,K,Na,P and the depletion of elements of Nb,Ta,Hf,and Th.In addition,it displays relative enrichment of Rb,Sr,and Ba.Geochemistry characteristics of the Jiang Tso ophiolite indicate it is of supra-subduction zone type ophiolite and formed in the spreading ridge of back arc basin.The zircon SHRIMP U-Pb weighted average ages of gabbro is 189.8±3.3 Ma (MSWD=0.97),which sug-gests that the extension time of Tethys oceanic basin in Jiang Tso region was consistent with the formation time of the Dongqiao oceanic basin in the middle part,and also corresponding to that of the oceanic basin in the western part,while later than the development of oceanic basin in the eastern part of the Bangonghu-Nujiang suture zone.From the geochronological da-ta,it can be deduced that the development of the Bangonghu-Nujiang oceanic basin was characterized by being gradually later from east to west.
Keywords：Jiang Tso ophiolitegeochemistrySHRIMP U-Pb datingtectonic environmentTibet
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：15( 34-48 )