气候变化领域集成服务门户(CCPortal): Petrogenesis of the Ramba leucogranite in the Tethyan Himalaya and constraints on the channel flow model

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DOI	10.1016/j.lithos.2014.08.022
	Petrogenesis of the Ramba leucogranite in the Tethyan Himalaya and constraints on the channel flow model
	Liu, Zhi-Chao; Wu, Fu-Yuan; Ji, Wei-Qiang; Wang, Jian-Gang; Liu, Chuan-Zhou
通讯作者	Liu, ZC (通讯作者)
发表日期	2014
ISSN	0024-4937
EISSN	1872-6143
起始页码	118
结束页码	136
卷号	208
英文摘要	The Himalayan leucogranites are critical for understanding the geodynamic process of Himalayan orogenesis. In this article, we present petrological, geochronological and geochemical results of the Ramba leucogranites that crop out in the center of the Ramba dome within the Tethyan Himalaya. U-(Th)-Pb dating of zircon, monazite and xenotime revealed three episodes of leucogranitic magmatism in the Ramba dome at ca. 44 Ma, ca. 28 Ma and ca. 8 Ma, respectively. The ca. 44 Ma and ca. 28 Ma magmatisms are both represented by strongly deformed porphyritic two-mica granite gneiss dykes that intruded into the margin of the dome. These granite gneisses have high CaO and Sr contents, relatively high Na/K, Sr/Y and low Rb/Sr ratios, and much lower initial Sr-87/Sr-86 ratios but higher epsilon(Nd)(t) and epsilon(Hf)(t) values than the ancient Indian crustal material. These results indicate that the granite gneisses were not derived from metasedimentary rocks of the High Himalayan Sequence but most likely were derived from partial melting of mafic rocks at a thickened crustal condition. The ca. 8 Ma leucogranites consist of a two-mica granite pluton in the core of the dome and garnet-bearing granite dykes in the margin of the dome. Major and trace element compositions indicate that these Miocene leucogranites are typical S-type granites and were most likely derived from muscovite and/or biotite dehydration melting of metapelites. The relatively lower TiO2, TFeO, MgO and CaO contents, higher Rb concentration and Rb/Sr ratio, and more strongly negative Eu anomaly of the garnet-bearing granite indicate that it was more evolved than the coeval two-mica granite. The non-CHARAC (CHarge-And-Radius-Controlled) trace element behavior and the tetrad effect of the REE distribution of the garnet-bearing granite further suggest that it is a highly fractionated granite. Besides, our study detected some Asian-like materials in the Ramba leucogranites, such as Mesozoic-aged inherited zircons and the relatively depleted Sr-Nd-Hf isotopic compositions of some leucogranite samples. These features of leucogranites in the Tethyan Himalaya have been previously considered as direct geological evidence for the channel flow model. However, detailed geochronological and geochemical studies of the country rocks suggest that these Asian-like materials are most likely sourced from the country rock rather than the Asian lithosphere, thus they may not be used as solid evidence for the channel flow model. (C) 2014 Elsevier B.V. All rights reserved.
关键词	MAIN CENTRAL THRUST ZIRCON U-PB SOUTH TIBETAN DETACHMENT USGS REFERENCE MATERIALS INDIA-ASIA COLLISION MALASHAN GNEISS DOME TECTONIC EVOLUTION GEOCHEMICAL CONSTRAINTS MANASLU LEUKOGRANITE ISOTOPIC CONSTRAINTS
英文关键词	Himalaya; Leucogranite; Highly fractionated crystallization; Channel flow
语种	英语
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000345179900009
来源期刊	LITHOS
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/258257
推荐引用方式 GB/T 7714	Liu, Zhi-Chao,Wu, Fu-Yuan,Ji, Wei-Qiang,et al. Petrogenesis of the Ramba leucogranite in the Tethyan Himalaya and constraints on the channel flow model[J]. 中国科学院青藏高原研究所,2014,208.
APA	Liu, Zhi-Chao,Wu, Fu-Yuan,Ji, Wei-Qiang,Wang, Jian-Gang,&Liu, Chuan-Zhou.(2014).Petrogenesis of the Ramba leucogranite in the Tethyan Himalaya and constraints on the channel flow model.LITHOS,208.
MLA	Liu, Zhi-Chao,et al."Petrogenesis of the Ramba leucogranite in the Tethyan Himalaya and constraints on the channel flow model".LITHOS 208(2014).