Neoarchean-Paleoproterozoic multiple tectonothermal events in the;western Alxa block, North China Craton and their geological implication:;Evidence from zircon U-Pb ages and Hf isotopic composition

doi:10.1016/j.precamres.2013.05.002

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	Neoarchean-Paleoproterozoic multiple tectonothermal events in the;western Alxa block, North China Craton and their geological implication:;Evidence from zircon U-Pb ages and Hf isotopic composition
	Zhang, Jianxin 4; Gong, Jianghua ; Yu, Shengyao ; Li, Huaikun 1; Hou, Kejun 2
刊名	PRECAMBRIAN RESEARCH
	2013
卷号	235 页码:36-57
关键词	Alxa block North China Craton U-Pb dating Hf isotope Neoarchean-Paleoproterozoic
ISSN号	0301-9268;EI 1872-7433
DOI	10.1016/j.precamres.2013.05.002
英文摘要	The Alxa block was traditionally considered to be part of the North China Craton, but its metamorphic basement has been poorly studied. Here we present a systematic zircon U-Pb and Hf isotopic investigation on four orthogneiss samples in the Beidashan area of the western Alxa block. The petrographic and geochemical data show that these rocks are granodioritic and trondhjemitic gneisses with TTG (tonalite-trondhjemite-granodiorite) characteristics. Zircons from the TTG gneisses display typical core-rim or core-mantle-rim structures. U-Pb datings and Hf isotopic analyses reveal two distinct age populations: the Latest Neoarchean (similar to 2.5 Ga) and the Late Palaeoproterozoic (similar to 1.85 Ga). The magmatic zircon cores and metamorphic mantles (rims) of the TTG gneisses were dated at similar ages around 2.5 Ga, supporting the existence of Archean rocks in the western Alxa block. The short time interval between the Latest Neoarchean magmatism and the subsequent metamorphism suggests that they were related to the same Latest Neoarchean tectonothermal event. The similar to 2.5 Ga zircons have epsilon Hf(t) mainly between 0.8 and 5.0, T-DM (Hf) model ages mainly between 2.6 and 2.8 Ga (with a peak at similar to 2.7 Ga) and T-DMC (Hf) model ages mainly between 2.7 and 3.0 Ga (with a peak at similar to 2.8 Ga). The age of similar to 1.85 Ga obtained from two trondhjemitic gneisses is interpreted as the age of the late Paleoproterzoic high-grade metamorphism. Our combined datasets show that the TTG gneisses in the Baidashan area of the western Alxa block experienced a main 2.7-2.8 Ga crust growth, a similar to 2.5 Ga magmatic-metamorphic event and a similar to 1.85 Ga high-grade metamorphic event. The sequence of events is very similar to that of the other North China Craton. A Combination of the data of Paleoproterozoic metamorphic rocks in the Alxa block suggests that the Alxa block is the western extension of the Khondalite Belt rather than the Yinshan block. (C) 2013 Elsevier B.V. All rights reserved.
学科主题	前寒武纪地质
WOS关键词	LA-ICP-MS ; PRECAMBRIAN CONTINENTAL-CRUST ; LIAO-JI BELT ; KHONDALITE BELT ; METAMORPHIC EVENTS ; JINING COMPLEX ; KEY ISSUES ; MESOPROTEROZOIC ; SUPERCONTINENT ; COLUMBIA SUPERCONTINENT ; TECTONIC EVOLUTION
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000328522400003
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40188]
专题	中国地质调查局天津地质调查中心
作者单位	1.Chinese Acad Geol Sci, Inst Geol, State Key Lab Continental Tecton & Dynam, Beijing 100037, Peoples R China. 2.CGS, Tianjin Inst Geol & Mineral Resources, Tianjin 300170, Peoples R China. 3.Chinese Acad Geol Sci, Inst Mineral Resources, Beijing 100037, Peoples R China. 4.中国地质科学院地质研究所
推荐引用方式 GB/T 7714	Zhang, Jianxin,Gong, Jianghua,Yu, Shengyao,et al. Neoarchean-Paleoproterozoic multiple tectonothermal events in the;western Alxa block, North China Craton and their geological implication:;Evidence from zircon U-Pb ages and Hf isotopic composition[J]. PRECAMBRIAN RESEARCH,2013,235:36-57.
APA	Zhang, Jianxin,Gong, Jianghua,Yu, Shengyao,Li, Huaikun,&Hou, Kejun.(2013).Neoarchean-Paleoproterozoic multiple tectonothermal events in the;western Alxa block, North China Craton and their geological implication:;Evidence from zircon U-Pb ages and Hf isotopic composition.PRECAMBRIAN RESEARCH,235,36-57.
MLA	Zhang, Jianxin,et al."Neoarchean-Paleoproterozoic multiple tectonothermal events in the;western Alxa block, North China Craton and their geological implication:;Evidence from zircon U-Pb ages and Hf isotopic composition".PRECAMBRIAN RESEARCH 235(2013):36-57.