Middle-Late Jurassic magmatism in the west central Lhasa subterrane, Tibet: Petrology, zircon chronology, elemental and Sr-Nd-Pb-Hf-Mg isotopic geochemistry

doi:10.1016/j.lithos.2021.106549

CORC > 海洋研究所 > 中国科学院海洋研究所

	Middle-Late Jurassic magmatism in the west central Lhasa subterrane, Tibet: Petrology, zircon chronology, elemental and Sr-Nd-Pb-Hf-Mg isotopic geochemistry
	Tong, Xin 5,6,7; Yan, Jingjing 4,7; Zhao, Zhidan 7; Niu, Yaoling 1,2,3,7; Qi, Ningyuan 7; Shi, Qingshang 7; Liu, Dong 7; Wang, Qing 7; Zhang, Liang-Liang 7; Dong, Guochen 7
刊名	LITHOS
	2022
卷号	408-409 页码:19
关键词	Tonalite Sr-Nd-Pb-Mg isotope Geochronology Tethyan Bangong-Nujiang Ocean Lhasa terrane
ISSN号	0024-4937
DOI	10.1016/j.lithos.2021.106549
通讯作者	Zhao, Zhidan(zdzhao@cugb.edu.cn)
英文摘要	Mesozoic magmatic rocks are widespread in the Lhasa terrane, but most of them are of cretaceous age. Because Jurassic rocks are relatively rare and our knowledge on such earlier magmatism in the context of the tectonic setting and evolution is limited. In this study, we focus on the mid-late Jurassic granitoids that occur in the west central Lhasa subterrane. We present the results of a systematic study of these granitoid rocks of tonalite composition together with the hosted mafic magmatic enclaves. We dated 4 representative tonalite samples and 2 enclaves using zircon U-Pb method that gives the age range of 167-154 Ma. All these samples have Sr-Nd-Pb isotopic compositions (Sr-87/Sr-86 = 0.713941-0.718417, epsilon(Nd)(t) = -14 to -9.8, Pb-206/Pb-204 = 18.806-18.936, Pb-207/Pb-204 = 15.739-15.764, Pb-208/Pb-204 = 39.257-39.798) similar to the composition of gneisses from the basement of the Lhasa terrane, suggesting that magmas parental to these mid-late Jurassic granitoids of tonalitic composition are of largely crustal origin, which is also supported by the petrographic observations. Both of the tonalite samples and the mafic enclaves have a wide span of zircon epsilon(Hf)(t) of -15.9 to -0.2 and -13.8 to -7.4, respectively. These samples also show varying delta Mg-26 ranging from -0.40 to -0.18, with an average delta Mg-26 = -0.27 +/- 0.06 parts per thousand (2SD) that is best understood as representing the Mg composition of the continental crust of the Lhasa terrane. All these observations allow us to conclude that basaltic melts derived from metasomatized mantle were involved in the petrogenesis of these granitoids. Specifically, southward subduction of the Bangong-Nujiang Ocean lithosphere and subsequent slab rollback metasomatized the mantle wedge and the lithospheric mantle above, whose melting produced basaltic magmas. Underplating and intrusion of these basaltic magmas caused crustal melting and generation of granitoid magmas parental to the tonalite and enclaves we study.
资助项目	Second Tibetan Plateau Scientific Expedition and Research (STEP) program[2019QZKK0702] ; National Key Research and Development Project of China[2016YFC0600304] ; Natural Science Foundation of China[41802058] ; Natural Science Foundation of China[9206220026] ; Natural Science Foundation of China[42073035] ; 111 Project of the Ministry of Science and Technology of China[B18048]
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:000762367900001
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/178185]
专题	中国科学院海洋研究所
通讯作者	Zhao, Zhidan
作者单位	1.Chinese Acad Sci, Inst Oceanol, Qingdao 266071, Peoples R China 2.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Geol, Qingdao 266061, Peoples R China 3.Univ Durham, Dept Earth Sci, Durham DH1 3LE, England 4.Chinese Acad Agr Sci, Inst Qual Stand & Testing Technol Agroprod, Key Lab Agroprod Qual & Safety, Minist Agr & Rural Affairs, Beijing 100081, Peoples R China 5.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China 6.China Geol Survey, Tianjin Ctr, Tianjin 300170, Peoples R China 7.China Univ Geosci, Sch Earth Sci & Resources, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China
推荐引用方式 GB/T 7714	Tong, Xin,Yan, Jingjing,Zhao, Zhidan,et al. Middle-Late Jurassic magmatism in the west central Lhasa subterrane, Tibet: Petrology, zircon chronology, elemental and Sr-Nd-Pb-Hf-Mg isotopic geochemistry[J]. LITHOS,2022,408-409:19.
APA	Tong, Xin.,Yan, Jingjing.,Zhao, Zhidan.,Niu, Yaoling.,Qi, Ningyuan.,...&Zhu, Di-Cheng.(2022).Middle-Late Jurassic magmatism in the west central Lhasa subterrane, Tibet: Petrology, zircon chronology, elemental and Sr-Nd-Pb-Hf-Mg isotopic geochemistry.LITHOS,408-409,19.
MLA	Tong, Xin,et al."Middle-Late Jurassic magmatism in the west central Lhasa subterrane, Tibet: Petrology, zircon chronology, elemental and Sr-Nd-Pb-Hf-Mg isotopic geochemistry".LITHOS 408-409(2022):19.