气候变化领域集成服务门户(CCPortal): Mid-Eocene high Sr/Y granites in the Northern Himalayan Gneiss Domes: Melting thickened lower continental crust

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DOI	10.1016/j.epsl.2011.01.005
	Mid-Eocene high Sr/Y granites in the Northern Himalayan Gneiss Domes: Melting thickened lower continental crust
	Zeng, Lingsen; Gao, Li-E; Xie, Kejia; Jing Liu-Zeng
通讯作者	Zeng, LS (通讯作者)
发表日期	2011
ISSN	0012-821X
EISSN	1385-013X
起始页码	251
结束页码	266
卷号	303 期号:3-4
英文摘要	Within the Himalayan collisional belt, granotoids occur along two sub-parallel belts, the Northern Himalayan Gneiss Domes (NHGD) and the High Himalayan Crystalline Series (HHCS). In the Yardoi area of NHGD, two-mica granite, a new type granite occurs in the core of the Yardoi gneiss dome (YGD), Dala and Quedang from north to south, and extends at least 50 km long. These granites have similar mineral composition, elemental and radiogenic isotope geochemistry, and age of formation. SHRIMP zircon U/Pb dating indicates that the Yardoi and the Quedang two-mica granites formed at 42.6 +/- 1.1 Ma and 42.8 +/- 0.6 Ma, respectively, similar to the Dala pluton. These two-mica granites have (1) high SiO2 (> 68 wt.%), Al2O3 (> 15 wt.%), and A/CNK(> 1.0); (2) relatively high Stand LREE, but low Y(< 10 ppm) and Yb (< 1 ppm); (3) high Sr/Y (> 40 and up to 250) and La/Yb (> 30); (4) very weak or no Eu anomalies; and (5) as compared with those in the Himalayan leucogranites, low initial Sr (Sr-87/Sr-86(i)< 0.7120) and similarly unradiogenic Nd (epsilon(Nd)(i)= -8.9 - 15.0) isotopic compositions. These granites have initial Sr and Nd isotope compositions similar to those in the amphibolites but significantly different from those in the metapelite and granitic gneiss. Two-mica granites from the Yardoi area are of peraluminous granite with relatively high Na/K and Sr/Y ratios. Such features are distinct from those in the younger leucogranites along the HHCS as well as in the NHGD, and require melting of source consisting dominantly of amphibolite at thickened crustal conditions. This is also supported by the presence of amphibolites with similar Sr and Nd isotope compositions, and similar ages of metamorphism. Two-mica granites of similar age also occur in the other NHGD gneiss domes and along the HHCS belt, implying that Mid-Eocene melting of thickened crustal materials was widespread and might be a primary factor that led to the formation of high density materials (e.g. eclogitic rocks) beneath the Tethyan Himalaya. (C) 2011 Elsevier B.V. All rights reserved.
关键词	ND-ISOTOPE DISEQUILIBRIUM SOUTHERN SIERRA-NEVADA INDIA-ASIA COLLISION U-PB ZIRCON TECTONIC EVOLUTION EXHUMATION HISTORY SLAB BREAKOFF GEOCHEMICAL CONSTRAINTS REGIONAL METAMORPHISM TETHYAN HIMALAYA
英文关键词	Northern Himalayan Gneiss Domes; crustal anatexis; leucogranite; high Sr/Y granite; High Himalaya; Tibet
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000288881900009
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/257875
推荐引用方式 GB/T 7714	Zeng, Lingsen,Gao, Li-E,Xie, Kejia,et al. Mid-Eocene high Sr/Y granites in the Northern Himalayan Gneiss Domes: Melting thickened lower continental crust[J]. 中国科学院青藏高原研究所,2011,303(3-4).
APA	Zeng, Lingsen,Gao, Li-E,Xie, Kejia,&Jing Liu-Zeng.(2011).Mid-Eocene high Sr/Y granites in the Northern Himalayan Gneiss Domes: Melting thickened lower continental crust.EARTH AND PLANETARY SCIENCE LETTERS,303(3-4).
MLA	Zeng, Lingsen,et al."Mid-Eocene high Sr/Y granites in the Northern Himalayan Gneiss Domes: Melting thickened lower continental crust".EARTH AND PLANETARY SCIENCE LETTERS 303.3-4(2011).