气候变化领域集成服务门户(CCPortal): Subduction of the Bangong-Nujiang Ocean: constraints from granites in the Bangong Co area, Tibet

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DOI	10.1002/gj.2510
	Subduction of the Bangong-Nujiang Ocean: constraints from granites in the Bangong Co area, Tibet
	Liu, Deliang; Huang, Qishuai; Fan, Shuaiquan; Zhang, Liyun; Shi, Rendeng; Ding, Lin
通讯作者	Liu, DL (通讯作者)
发表日期	2014
ISSN	0072-1050
EISSN	1099-1034
起始页码	188
结束页码	206
卷号	49 期号:2
英文摘要	We report geochronologic, whole-rock geochemical and Sr-Nd isotopic analyses of the granites that are exposed to both the north and the inside of the Bangong-Nujiang Suture (BNS) zone as well as the implications for the Mesozoic history of Tibet. To the north of the BNS, the Larelaxin pluton consists of I-type quartz diorite and highly fractionated I-type biotite granite. The Larelaxin pluton is enriched in large-ion lithophile elements (LILE) but depleted in high-field-strength elements (HFSE); therefore, it exhibits the features of volcanic arc rocks. The initial Sr (0.7102 to 0.7215) and negative epsilon Nd (t) (-2.91 to -5.20) values imply a mixture of depleted mantle and continental crust. The mean Pb-206/U-238 zircon age is 168 Ma; we therefore propose that the Bangong-Nujiang Ocean (BNO) had already been subducted beneath the Qiangtang terrain by the middle Jurassic. Inside the BNS, the Rutog granites intruded into the Lagongtang and Duoren formations, which show a continental margin and a forearc basin sedimentary facies, respectively. The mean Pb-206/U-238 zircon age is 101 Ma. The Rutog granites are monzogranites with a high Na/K ratio (Na2O/K2O > 1) and a high LILE/HFSE ratio, and A/CNK < 1.1. The high Sr/Y ratio (22 to 56) implies that these granites are adakitic. The low initial Sr (0.7044 to 0.7055) and positive epsilon Nd (t) (+1.46 to +2.70) values indicate that the protolith of the Rutog granites originated mainly from a depleted source. We attribute the Rutog plutonism to the development of an oceanic arc during the continuing northward subduction of the BNO and propose that the Rutog adakitic granites were formed by melting of the subducted BNO crust with limited crustal contamination. Copyright (c) 2013 John Wiley & Sons, Ltd.
关键词	CONTINENTAL COLLISION ZONES ZIRCON U-PB TECTONIC EVOLUTION GANGDESE BATHOLITH GEOCHEMICAL CHARACTERISTICS QIANGTANG BLOCK SOUTHERN TIBET BASEMENT ROCKS I-TYPE OPHIOLITE
英文关键词	Bangong-Nujiang Ocean; granite; Tibet; U-Pb zircon age; subduction
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000333024000006
来源期刊	GEOLOGICAL JOURNAL
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/258264
推荐引用方式 GB/T 7714	Liu, Deliang,Huang, Qishuai,Fan, Shuaiquan,et al. Subduction of the Bangong-Nujiang Ocean: constraints from granites in the Bangong Co area, Tibet[J]. 中国科学院青藏高原研究所,2014,49(2).
APA	Liu, Deliang,Huang, Qishuai,Fan, Shuaiquan,Zhang, Liyun,Shi, Rendeng,&Ding, Lin.(2014).Subduction of the Bangong-Nujiang Ocean: constraints from granites in the Bangong Co area, Tibet.GEOLOGICAL JOURNAL,49(2).
MLA	Liu, Deliang,et al."Subduction of the Bangong-Nujiang Ocean: constraints from granites in the Bangong Co area, Tibet".GEOLOGICAL JOURNAL 49.2(2014).