Eocene melting of subducting continental crust and early uplifting of central Tibet: Evidence from central-western Qiangtang high-K calc-alkaline andesites, dacites and rhyolites

doi:10.1016/j.epsl.2008.04.034

	Eocene melting of subducting continental crust and early uplifting of central Tibet: Evidence from central-western Qiangtang high-K calc-alkaline andesites, dacites and rhyolites
	Wang, Qiang 1,2,3; Wyman, Derek A.2; Xu, Jifeng 1; Dong, Yanhui 1; Vasconcelos, Paulo M.4; Pearson, N.5; Wan, Yusheng 3; Dong, Han 6; Li, Chaofeng 7; Yu, Yuanshan 6
刊名	EARTH AND PLANETARY SCIENCE LETTERS
	2008-07-30
卷号	272 期号:1-2 页码:158-171
关键词	adakites high-Mg andesites peraluminous subduction uplift Eocene Qiangtang Tibet
ISSN号	0012-821X
DOI	10.1016/j.epsl.2008.04.034
文献子类	Review
英文摘要	Changes in oceanic O-Sr isotopic compositions and global cooling beginning in the Eocene are considered to have been caused by the uplift of the Tibetan Plateau. The specific timing and uplift mechanism, however, have long been subjects of debate. We investigated the Duogecuoren lavas of the central-western Qiangtang Block, which form the largest outcrops among Cenozoic lavas in northern-central Tibet and have widely been considered as shoshonitic. Our study demonstrates, however, that most of these lavas are high-K calc-alkaline andesites, clacites and rhyolites. Moreover, they are characterized by high Sr (367-2472 ppm) and Al2O3 (14.55-16.86 wt.%) and low Y (3.05-16.9 ppm) and Yb (0.31-1.48 ppm) contents and high La/Yb (27-100) and Sr/Y (48-240) ratios, similar to adakitic rocks derived by partial melting of an eclogitic source. They can be further classified as either peraluminous and rnetaluminous subtypes. The peraluminous rocks have relatively high SiO2 (>66 wt.%) con tents, and low MgO (< 1.0 wt.%), Cr (4.94-23.3 ppm) and Ni (2.33-17.0 ppm) contents and Mg-# (20-50) values, while the metaluminous rocks exhibit relatively low SiO2 (55-69 wt.%) contents, and high MgO (1.41-6.34), Cr (25.7-383 ppm), Ni (14.13-183 ppm) and Mg-# (46-69) values, similar to magnesian andesites. Ar-40/Ar-39 and SHRIMP zircon U-Pb dating reveal that both peralummous and metaluminous adakitic rocks erupted in the Eocene (46-38 Ma). Paleocene-Early Miocene thrust faults and associated syn-contractional basin deposits in the Qiangtang Block suggest that this region was undergoing crustal shortening within a continent during the Eocene. The low epsilon(Nd) (-2.81 to -6.91) and high Sr-87/Sr-86 (0.7057-0.7097), Th (11.2-32.3 ppm) and Th/La (0.23-0.88) values in the Duogecuoren adakitic rocks further indicate that they were not derived by partial melting of subducted oceanic Crust. Taking into account tectonic and geophysical data and the compositions of xenoliths in Cenozoic lava in northern-central Tibet, we suggest that the peraluminous adakitic rocks were most probably derived by partial melting of subducted sediment-dominated continent of the Songpan-Ganzi Block along the Jinsha suture to the north at a relatively shallow position (the hornblende garnet stability field), but the metaluminous adakitic rocks likely originated from the interaction between peraluminous adakitic melts generated at greater depths (the garnet+rutile stability field) and mantle. Because the Duogecuoren adakitic rocks must have originated from a garnet-bearing(namely, eclogite facies) source, Eocene continental subduction along the Jinsha Suture Caused the thickening of the Qiangtang crust. Given that crustal thickening generally equates with elevation, the uplift of the Central Tibetan Plateau probably began as early as 45-38 Ma, which provides important evidence for tectonically driven models of oceanic O-Sr isotope evolution during global cooling and Asian continental aridification beginning in the Eocene. (C) 2008 Elsevier B.V. All rights reserved.
WOS关键词	PB ZIRCON GEOCHRONOLOGY ; SETOUCHI VOLCANIC BELT ; INDO-ASIAN COLLISION ; SLAB-DERIVED MELTS ; NORTH CHINA CRATON ; HIGH-MG ANDESITES ; GARZE FOLD BELT ; HOH-XIL REGION ; TRACE-ELEMENT ; SOUTH CHINA
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000259119900016
资助机构	Chinese Academy of Sciences(KZCX3-SW-143 ; Chinese Academy of Sciences(KZCX3-SW-143 ; National Natural Science Foundation of China(40572042 ; National Natural Science Foundation of China(40572042 ; International Development Fund of The University of Sydney ; International Development Fund of The University of Sydney ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; Macquarie University and industry ; Macquarie University and industry ; KZCX2-YW-128) ; KZCX2-YW-128) ; 40673037 ; 40673037 ; 40425003) ; 40425003) ; Chinese Academy of Sciences(KZCX3-SW-143 ; Chinese Academy of Sciences(KZCX3-SW-143 ; National Natural Science Foundation of China(40572042 ; National Natural Science Foundation of China(40572042 ; International Development Fund of The University of Sydney ; International Development Fund of The University of Sydney ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; Macquarie University and industry ; Macquarie University and industry ; KZCX2-YW-128) ; KZCX2-YW-128) ; 40673037 ; 40673037 ; 40425003) ; 40425003) ; Chinese Academy of Sciences(KZCX3-SW-143 ; Chinese Academy of Sciences(KZCX3-SW-143 ; National Natural Science Foundation of China(40572042 ; National Natural Science Foundation of China(40572042 ; International Development Fund of The University of Sydney ; International Development Fund of The University of Sydney ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; Macquarie University and industry ; Macquarie University and industry ; KZCX2-YW-128) ; KZCX2-YW-128) ; 40673037 ; 40673037 ; 40425003) ; 40425003) ; Chinese Academy of Sciences(KZCX3-SW-143 ; Chinese Academy of Sciences(KZCX3-SW-143 ; National Natural Science Foundation of China(40572042 ; National Natural Science Foundation of China(40572042 ; International Development Fund of The University of Sydney ; International Development Fund of The University of Sydney ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; ARC LIEFARC LIEF and DEST Systemic Infrastructure Grants ; Macquarie University and industry ; Macquarie University and industry ; KZCX2-YW-128) ; KZCX2-YW-128) ; 40673037 ; 40673037 ; 40425003) ; 40425003)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/69391]
专题	中国科学院地质与地球物理研究所
通讯作者	Wang, Qiang
作者单位	1.Chinese Acad Sci, Key Lab Isotope Geochronol & Geochem, Guangzhou Inst Geochem, Guangzhou 510640, Guangdong, Peoples R China 2.Univ Sydney, Sch Geosci, Div Geol & Geophys, Sydney, NSW 2006, Australia 3.Chinese Acad Geol Sci, Beijing 100037, Peoples R China 4.Univ Queensland, Dept Earth Sci, Brisbane, Qld 4072, Australia 5.Macquarie Univ, ARC Natl Key Ctr Geochem Evolut & Metallogeny Con, Dept Earth & Planetary Sci, N Ryde, NSW 2109, Australia 6.Chengdu Inst Geol & Mineral Resources, Chengdu 610082, Peoples R China 7.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Wang, Qiang,Wyman, Derek A.,Xu, Jifeng,et al. Eocene melting of subducting continental crust and early uplifting of central Tibet: Evidence from central-western Qiangtang high-K calc-alkaline andesites, dacites and rhyolites[J]. EARTH AND PLANETARY SCIENCE LETTERS,2008,272(1-2):158-171.
APA	Wang, Qiang.,Wyman, Derek A..,Xu, Jifeng.,Dong, Yanhui.,Vasconcelos, Paulo M..,...&Chug, Zhuyin.(2008).Eocene melting of subducting continental crust and early uplifting of central Tibet: Evidence from central-western Qiangtang high-K calc-alkaline andesites, dacites and rhyolites.EARTH AND PLANETARY SCIENCE LETTERS,272(1-2),158-171.
MLA	Wang, Qiang,et al."Eocene melting of subducting continental crust and early uplifting of central Tibet: Evidence from central-western Qiangtang high-K calc-alkaline andesites, dacites and rhyolites".EARTH AND PLANETARY SCIENCE LETTERS 272.1-2(2008):158-171.