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DOI	10.1016/j.epsl.2018.03.034
	118-115 Ma magmatism in the Tethyan Himalaya igneous province: Constraints on Early Cretaceous rifting of the northern margin of Greater India
	Chen, Sheng-Sheng; Fan, Wei-Ming; Shi, Ren-Deng; Liu, Xiao-Han; Zhou, Xue-Jun
通讯作者	Chen, SS (通讯作者)
发表日期	2018
ISSN	0012-821X
EISSN	1385-013X
起始页码	21
结束页码	33
卷号	491
英文摘要	Understanding the dynamics of Large Igneous Provinces (LIPs) is critical to deciphering processes associated with rupturing continental lithosphere. Microcontinental calving, the rifting of microcontinents from mature continental rifted margins, is particularly poorly understood. Here we present new insights into these processes from geochronological and geochemical analyses of igneous rocks from the Tethyan Himalaya. Early Cretaceous mafic dikes are widely exposed in the eastern and western Tethyan Himalaya, but no such rocks have been reported from the central Tethyan Himalaya. Here we present an analysis of petrological, geochronological, geochemical, and Sr-Nd-Hf-Os isotopic data for bimodal magmatic rocks from the center-east Tethyan Himalaya. Zircon U-Pb dating yields six weighted-mean concordant Pb-206/U-238 ages of 118 +/- 1.2 to 115 +/- 1.3 Ma. Mafic rocks display MORB-like compositions with flat to depleted LREE trends, and positive epsilon(Nd)(t) (+2.76 to +5.39) and epsilon(Hf)(t) (+8.0 to +11.9) values. The negative Nb anomalies and relatively high Os-187/Os-188 ratios (0.15-0.19) of these rocks are related to variable degrees (up to 10%) of crustal contamination. Geochemical characteristics indicate that mafic rocks were generated by variable degrees (2-20%) of partial melting of spinel lherzolites in shallow depleted mantle. Felsic rocks are enriched in Th and LREE, with negative Nb anomalies and decoupling of Nd (epsilon(Nd)(t) = -13.39 to -12.78) and Hf (epsilon(Hf)(t) = -4.8 to -2.0), suggesting that they were derived mainly from garnet-bearing lower continental crust. The geochemical characteristics of the bimodal magmatic associations are comparable to those of associations that form in a continental rift setting. Results indicate that Early Cretaceous magmatism occurred across the whole Tethyan Himalaya, named here as the Tethyan Himalaya igneous province. Separation of the Tethyan Himalaya from the Indian craton may have occurred during ongoing Early Cretaceous extension related to the Kerguelen mantle plume during the nascent stages of a global plate-reorganization event. If this is the case, our findings provide clues to the nature of the Tethyan Himalaya, challenging traditional view of the India-Asia single-stage collision model. (C) 2018 Elsevier B.V. All rights reserved.
关键词	HF ISOTOPE CONSTRAINTS MANTLE AGE PETROGENESIS EVOLUTION COLLISION VESTIGES BASALTS MODEL TIBET
英文关键词	Tethyan Himalaya igneous province; Early Cretaceous; continental rift; bimodal magmatism; Sr-Nd-Hf-Os isotopes
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000432499200003
来源期刊	EARTH AND PLANETARY SCIENCE LETTERS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/259118
推荐引用方式 GB/T 7714	Chen, Sheng-Sheng,Fan, Wei-Ming,Shi, Ren-Deng,et al. 118-115 Ma magmatism in the Tethyan Himalaya igneous province: Constraints on Early Cretaceous rifting of the northern margin of Greater India[J]. 中国科学院青藏高原研究所,2018,491.
APA	Chen, Sheng-Sheng,Fan, Wei-Ming,Shi, Ren-Deng,Liu, Xiao-Han,&Zhou, Xue-Jun.(2018).118-115 Ma magmatism in the Tethyan Himalaya igneous province: Constraints on Early Cretaceous rifting of the northern margin of Greater India.EARTH AND PLANETARY SCIENCE LETTERS,491.
MLA	Chen, Sheng-Sheng,et al."118-115 Ma magmatism in the Tethyan Himalaya igneous province: Constraints on Early Cretaceous rifting of the northern margin of Greater India".EARTH AND PLANETARY SCIENCE LETTERS 491(2018).