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  4. 岩石圈演化国家重点实验室
Thickened juvenile lower crust-derived similar to 90 Ma adakitic rocks in the central Lhasa terrane, Tibet

文献类型：期刊论文

作者Sun, Gao-Yuan1; Hu, Xiu-Mian1; Zhu, Di-Cheng2,3; Hong, Wen-Tao4; Wang, Jian-Dang5; Wang, Qing2,3
刊名LITHOS
出版日期2015-05-01
卷号224页码:225-239
关键词Adaldtic rocks Crustal thickening Late Cretaceous Lhasa terrane Tibet
DOI10.1016/j.lithos.2015.03.010
文献子类Article
英文摘要The questions of why the Late Cretaceous magmatism generated and how the nature of the lower crust evolves in central Tibet remain poorly constrained. In this paper, we report the presence of early Late Cretaceous adakitic rocks from the Azhang area, northern edge of the central Lhasa subterrane, central Tibet. These rocks are rhyodacites/dacites in composition and have geochemical characteristics of adakitic rocks, e.g., high Sr (554-836 ppm), Sr/Y (66-100), and (La/Yb)N (20-21), low Y (7.96-8.96 ppm) and heavy rare earth elements (HREE). In situ zircon U-Pb dating for two samples yields an early Late Cretaceous age (90 +/- 1 Ma and 87 1 Ma). The low MgO (1.4-1.9 wt.%) contents and compatible element abundances (e.g., Cr = 22-30 ppm; Ni = 19-25 ppm) indicate that these rocks were most likely derived from the partial melting of a garnet-bearing amphibolite under a thickened lower crust condition. The positive whole-rock epsilon(Nd)(t) (+2.5 to + 5.6) and zircon epsilon(Hf)(t) (+8.9 to +16.0) values suggest that this thickened lower crust was juvenile. The crust beneath the central Lhasa subterrane may have been significantly thickened due to tectonic shortening in response to the Lhasa-Qiangtang collision and magma underplating before the emplacement of Azhang adakitic rocks (similar to 90 Ma). We argue that regional lithospheric delamination at similar to 90 Ma triggered the partial melting of the lowermost garnet-bearing crust that is still attached to the middle crust to generate the Azhang adakitic rocks. The presence of the similar to 90 Ma Azhang adakitic rocks provides valuable constraints on the origin of the early Late Cretaceous magmatism in the central Lhasa subterrane and on the crustal evolution beneath the Lhasa-Qiangtang collisional zone prior to the Cenozoic India-Asia collision. (C) 2015 Elsevier B.V. All rights reserved.
WOS关键词ZIRCON U-PB ; UNDERPLATED BASALTIC CRUST ; HF ISOTOPIC CONSTRAINTS ; INDO-ASIAN COLLISION ; SOUTHERN TIBET ; VOLCANIC-ROCKS ; CONTINENTAL-CRUST ; INTRUSIVE ROCKS ; EAST CHINA ; TECTONIC IMPLICATIONS
WOS研究方向Geochemistry & Geophysics ; Mineralogy
语种英语
WOS记录号WOS:000354342100015
资助机构National Key Project for Basic Research of China(2012CB822001 ; National Key Project for Basic Research of China(2012CB822001 ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences(XDB03010301) ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences(XDB03010301) ; Chinese National Natural Science Foundation(41472081 ; Chinese National Natural Science Foundation(41472081 ; 2015CB452604) ; 2015CB452604) ; 41225006 ; 41225006 ; 41472061) ; 41472061) ; National Key Project for Basic Research of China(2012CB822001 ; National Key Project for Basic Research of China(2012CB822001 ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences(XDB03010301) ; Strategic Priority Research Program (B) of the Chinese Academy of Sciences(XDB03010301) ; Chinese National Natural Science Foundation(41472081 ; Chinese National Natural Science Foundation(41472081 ; 2015CB452604) ; 2015CB452604) ; 41225006 ; 41225006 ; 41472061) ; 41472061)
源URL[http://ir.iggcas.ac.cn/handle/132A11/62528]  
专题地质与地球物理研究所_岩石圈演化国家重点实验室
作者单位1.Nanjing Univ, Sch Earth Sci & Engn, State Key Lab Mineral Deposits Res, Nanjing 210023, Jiangsu, Peoples R China
2.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China
3.China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China
4.China Geol Survey, Nanjing Inst Geol & Mineral Resources, Nanjing 210016, Jiangsu, Peoples R China
5.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
推荐引用方式
GB/T 7714		 Sun, Gao-Yuan,Hu, Xiu-Mian,Zhu, Di-Cheng,et al. Thickened juvenile lower crust-derived similar to 90 Ma adakitic rocks in the central Lhasa terrane, Tibet[J]. LITHOS,2015,224:225-239.
APA Sun, Gao-Yuan,Hu, Xiu-Mian,Zhu, Di-Cheng,Hong, Wen-Tao,Wang, Jian-Dang,&Wang, Qing.(2015).Thickened juvenile lower crust-derived similar to 90 Ma adakitic rocks in the central Lhasa terrane, Tibet.LITHOS,224,225-239.
MLA Sun, Gao-Yuan,et al."Thickened juvenile lower crust-derived similar to 90 Ma adakitic rocks in the central Lhasa terrane, Tibet".LITHOS 224(2015):225-239.

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来源：地质与地球物理研究所

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