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DOI	10.1016/j.jseaes.2011.09.003
	U-Pb geochronology of basement rocks in central Tibet and paleogeographic implications
	Guynn, Jerome; Kapp, Paul; Gehrels, George E.; Ding, Lin
通讯作者	Guynn, J (通讯作者)
发表日期	2012
ISSN	1367-9120
EISSN	1878-5786
起始页码	23
结束页码	50
卷号	43 期号:1
英文摘要	The ages and paleogeographic affinities of basement rocks of Tibetan terranes are poorly known. New U-Pb zircon geochronologic data from orthogneisses of the Amdo basement better resolve Neoproterozoic and Cambro-Ordovician magmatism in central Tibet. The Amdo basement is exposed within the Bangong suture zone between the Lhasa and Qiangtang terranes and is composed of granitic orthogneisses with subordinate paragneisses and metasedimentary rocks. The intermediate-felsic orthogneisses show a bimodal distribution of Neoproterozoic (920-820 Ma) and Cambro-Ordovician (540-460 Ma) crystallization ages. These and other sparse basement ages from Tibetan terranes suggest the plateau is underlain by juvenile crust that is Neoproterozoic or younger; its young age and weaker rheology relative to eratonic blocks bounding the plateau margins likely facilitated the propagation of lndo-Asian deformation far into Asia. The Neoproterozoic ages post-date Rodinia assembly and magmatism of similar ages is documented in the Qaidaim-Kunlun terrane, South China block, the Aravalli-Delhi craton in NW India, the Eastern Ghats of India, and the Prince Charles mountains in Antarctica. The Amdo Neoproterozoic plutons cannot be unambiguously related to one of these regions, but we propose that the Yangtze block of the South China block is the most likely association, with the Amdo basement representing a terrane that possibly rifted from the active Yangtze margin in the middle Neoproterozoic. Cambro-Ordovician granitoids are ubiquitous throughout Gondwana as a product of active margin tectonics following Gondwana assembly and indicate that the Lhasa-Qiangtang terranes were involved in these tectono-magmatic events. U-Pb detrital zircon analysis of two quartzites from the Amdo basement suggest that the protoliths were Carboniferous-Permian continental margin strata widely deposited across the Lhasa and Qiangtang terranes. The detrital zircon age spectra of the upper Paleozoic Tibetan sandstones and other rocks deposited in East Gondwana during the late Neoproterozoic and Paleozoic are all quite similar, making it difficult to use the age spectra for paleogeographic determinations. There is a suggestion in the data that the Qiangtang terrane may have been located further west along Gondwana's northern boundary than the Lhasa terrane, but more refined spatial and temporal data are needed to verify this configuration. (C) 2011 Elsevier Ltd. All rights reserved.
关键词	NEOPROTEROZOIC TECTONIC EVOLUTION DETRITAL ZIRCON GEOCHRONOLOGY HF ISOTOPIC CONSTRAINTS WESTERN YANGTZE BLOCK SOUTH CHINA LHASA TERRANE BREAK-UP GEOCHEMICAL EVIDENCE METAMORPHIC ROCKS SICHUAN PROVINCE
英文关键词	Amdo; Qiangtang; Lhasa; Tibet; Zircon; Paleogeography
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000297881500003
来源期刊	JOURNAL OF ASIAN EARTH SCIENCES
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/258030
推荐引用方式 GB/T 7714	Guynn, Jerome,Kapp, Paul,Gehrels, George E.,et al. U-Pb geochronology of basement rocks in central Tibet and paleogeographic implications[J]. 中国科学院青藏高原研究所,2012,43(1).
APA	Guynn, Jerome,Kapp, Paul,Gehrels, George E.,&Ding, Lin.(2012).U-Pb geochronology of basement rocks in central Tibet and paleogeographic implications.JOURNAL OF ASIAN EARTH SCIENCES,43(1).
MLA	Guynn, Jerome,et al."U-Pb geochronology of basement rocks in central Tibet and paleogeographic implications".JOURNAL OF ASIAN EARTH SCIENCES 43.1(2012).