Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane,Southern Tibet:Implications for the Evolution of the Sumdo Paleo-Tethys OceanOACSTPCD
Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane,Southern Tibet:Implications for the Evolution of the Sumdo Paleo-Tethys Ocean
Basalts from the Late Carboniferous to Early Permian are extensively developed in the central Lhasa subterrane,southern Tibet.Studying the petrogenesis of these rocks may have implications for the late Paleozoic arc magmatism along the central Lhasa subterrane uncovering more of the evolution of the Sumdo Paleo-Tethys Ocean and its dynamic mechanism.Basalt samples from the Luobadui Formation in the Leqingla area,NW of Linzhou City in the central Lhasa subterrane,southern Tibet exhibit arc-like geochemical signatures in a subduction-zone tectonic setting characterized by high Al2O3 and low TiO2 contents,fractionated REE patterns with low Nb/La ratios and high LREE concentrations,and negative HFSE anomalies.Based on their higher Th/Ce,Nb/Zr,and lower Ba/Th,Pb/Nd ratios,slightly negative to positiveεNd(t)values,and the relatively high Sr-Pb isotopic compositions,these samples were probably derived from partial melting of a depleted mantle source of garnet+spinel lherzolite,metasomatized by subducted sediments around 297 Ma.Modeling of the trace elements indicates that these basalts experienced fractional crystallization of olivine,clinopyroxene and minor plagioclase during magma ascent and eruption.It is proposed that these Late Carboniferous-Early Permian basalts are associated with the northward subduction of the Sumdo Paleo-Tethys Ocean seafloor along the southern margin of the central Lhasa subterrane.
MA Wang;LIU Yingchao;YANG Zhusen;Jan-Marten HUIZENGA;LI Zhenqing;YUE Longlong;ZHAO Sibo
School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China||Institute of Geology,Sinoprobe Laboratory,Chinese Academy of Geological Sciences,Beijing 100037,ChinaInstitute of Geology,Sinoprobe Laboratory,Chinese Academy of Geological Sciences,Beijing 100037,ChinaMLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,ChinaFaculty of Environmental Sciences and Natural Resource Management,Norwegian University of Life Sciences,NO-1432 Ås,Norway||Economic Geology Research Centre(EGRU),College of Science and Engineering,James Cook University,Townsville,Queensland 4811,Australia||Department of Geology,University of Johannesburg,Auckland Park 2006,South Africa
geochemistrynorthward subductionSumdo Paleo-Tethys OceanLhasa terraneTibet
《地质学报（英文版）》 2024 (004)
955-968 / 14
We are grateful to the staff of the Tianguansanqin Company and Xu Yutao,Mao Jingtao,and Li Jun for their assistance during the fieldwork.This research was co-supported by the National Key Research and Development Program of China(Grant No.2022YFF0800903),the National Natural Science Foundation of China(Grant Nos.42302107,92162322,42261144669,41922022,42003036),the China Geological Survey(Grant Nos.DD20243512,DD20230008),the National Postdoctoral Research Program of China(Grant No.GZC20232489),the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2021QZKK0304),XingDian Youth Talent Plan of Yunnan Province(Grant No.XDYC-QNRC-2022-0136),and the UNESCO:IUGS IGCP-662 Program;this is a contribution to the latter project:'Orogen architecture and crustal growth from accretion to collision'.Constructive comments and suggestions from two anonymous reviewers significantly improved the paper.
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