Fluxed melting of metapelite and the formation of Miocene high-CaO two-mica granites in the Malashan gneiss dome, southern Tibet

doi:10.1016/j.gca.2014.01.003

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	Fluxed melting of metapelite and the formation of Miocene high-CaO two-mica granites in the Malashan gneiss dome, southern Tibet
	Gao, Li-E.3; Zeng, Lingsen 1
刊名	GEOCHIMICA ET COSMOCHIMICA ACTA
	2014
卷号	130 页码:136-155
ISSN号	0016-7037
DOI	10.1016/j.gca.2014.01.003
英文摘要	Identifying the timing of formation and geochemical nature of the Cenozoic granites along the Himalayan orogen is essential to test or formulate models that link crustal anatexis with tectonic transition during the evolution of large-scale collisional orogenic belts. The Malashan gneiss dome, one of the prominent domes within the Tethyan Himalaya, experienced Barrovian-type metamorphism and partial melting of pelitic rocks at relatively deep levels during the collision between India and Eurasia. New LA-MC-ICP-MS zircon U-Pb analyses yielded that the Malashan two-mica granites formed at a time span of 17.6 +/- 0.1 to 16.9 +/- 0.1 Ma. The Malashan two-mica granites are characterized by: (1) high SiO2 (>71.3 wt.%), Al2O3 (>14.8 wt.%), and relatively high CaO (>1.3 wt.%); (2) relatively high Sr (>146 ppm), but low Rb/Sr ratios (<1.3) which are nearly constant relative to large variations in Ba concentrations; (3) enrichment in LREE, depletion in HREE, and no or weak negative Eu anomalies (Eu/Eu* = 0.7-0.9); (4) as compared to granites in the other Northern Himalayan Gneiss Domes and High Himalayan Belt, relatively lower initial Sr-87/Sr-86 ratios (0.7391-0.7484) and similar unradiogenic Nd isotope compositions (epsilon(Nd)(t) = -13.7 to -14.4). These characteristics imply that the two-mica granites were derived from fluid-fluxing melting of metapelite, possibly triggered by the E-W extension. Our new data in combination with literature data indicate that there are three types of granites with diverse geochemical characteristics and distinct formation mechanisms along the Himalayan orogen since the Cenozoic India-Eurasia continental collision. Conceivably, our new results will provide new insights on how the partial melting behavior of relatively deeper crustal rocks evolved as the tectonic evolution of large orogenic belts. Crown copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.
学科主题	变质岩岩石学
WOS关键词	THICKENED CONTINENTAL-CRUST ; NATURAL REFERENCE MATERIAL ; EAST-WEST EXTENSION ; U-PB ZIRCON ; HIMALAYAN LEUKOGRANITES ; GEOLOGICAL IMPLICATIONS ; GEOCHEMICAL CONSTRAINTS ; REGIONAL METAMORPHISM ; TECTONIC IMPLICATIONS ; MANASLU LEUCOGRANITE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000332405700010
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40479]
专题	中国地质调查局
作者单位	1.[Gao, Li-E. 2.Chinese Acad Geol Sci, Inst Geol, State Key Lab Continental Tecton & Dynam, Beijing 100037, Peoples R China 3.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Gao, Li-E.,Zeng, Lingsen. Fluxed melting of metapelite and the formation of Miocene high-CaO two-mica granites in the Malashan gneiss dome, southern Tibet[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2014,130:136-155.
APA	Gao, Li-E.,&Zeng, Lingsen.(2014).Fluxed melting of metapelite and the formation of Miocene high-CaO two-mica granites in the Malashan gneiss dome, southern Tibet.GEOCHIMICA ET COSMOCHIMICA ACTA,130,136-155.
MLA	Gao, Li-E.,et al."Fluxed melting of metapelite and the formation of Miocene high-CaO two-mica granites in the Malashan gneiss dome, southern Tibet".GEOCHIMICA ET COSMOCHIMICA ACTA 130(2014):136-155.