Tectonic affinity and timing of two types of amphibolites within the Qinling Group, north Qinling orogenic belt

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	Tectonic affinity and timing of two types of amphibolites within the Qinling Group, north Qinling orogenic belt
	Yan, QR (Yan QuanRen); Wang, ZQ (Wang ZongQi); Yan, Z (Yan Zhen); Chen, JL (Chen JunLu); Xiang, ZJ (Xiang ZhongJin); Wang, T (Wang Tao); Zhang, HY (Zhang HongYuan)
刊名	ACTA PETROLOGICA SINICA
	2009
卷号	25 期号:9 页码:2177-2194
关键词	Qinling Group Amphibolites SHRIMP U-Pb analysis Ar/Ar dating
ISSN号	1000-0569
英文摘要	There are two types of amphibolites within the Qinling Group, north qinling orogenic belt. One is layer-liked or blocked amphibolites involved in marbles, another is the dikes Of amphibolites intruding into mica-schist, indicative of significant differences of petrogenesis and time between two types of amphibolites. Geochemistry shows that the Protolithes of two types of amphibolites are basaltic. The dikes of amphibolites were formed in a tectonic setting of the within-plate, and isotopes Of Strontium and neodymium indicate that magma of those dikes sourced from depleted mantle. SHRIMP U-Pb analyses for zircons show that the dikes were formed in the Late Ordovician, ca. 449 +/- 11 Ma, and (40)Ar/(39) Ar dating results reveral that those dikes underwent amphibolite facies metamorphism at the end of the Carboniferous, ca. 301.3 +/- 6.4Ma. In comparison, layer-liked or blocked amphibolites involved in marbles of the Qinling Group show the geochemical kind isotopic affinity with oceanic island basalls, or seamount basalts. (40)Ar/(39) Ar dating results show that this type of amphibolite underwent amphibolite facies metamorphism in the Late Permian, ca.258.1 +/- 5.7Ma, later about 40Ma than the dikes. Difference of tectonic affinities and timings, and similar metamorphism and ages suggest that two types of amphibolites in the Qinling Group are belonged to different tectonic blocks, and then assembled together to constructed a high-graded metamorphic terrane, that is the Qinling Group. In conclusion, this paper suggests that the dikes of amphibolites intruding into the mica-schist were products of crust extension or lithospheric delamination and thinning triggered by thermal contraction during the post Caledonian orogen in the north Qinling orogenic belt. While layer-liked or blocked amphibolite involved in marbles might be the assemblages of basic extrusive rocks and carbonate cap of the oceanic rises, such as the OIBs and seamounts, most likely. Those oceanic rises were allochthonous in the Middle Permian.
学科主题	构造地质学
WOS关键词	VOLCANIC-ROCKS ; U-PB ; AGES ; CLASSIFICATION ; GRANULITE ; EVOLUTION ; ND
WOS研究方向	Geology
语种	中文
出版者	SCIENCE PRESS
WOS记录号	WOS:000270044500012
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38981]
专题	中国地质调查局
作者单位	China Univ Geosci, Sch Geosci & Resources, Beijing 100083, Peoples R China
推荐引用方式 GB/T 7714	Yan, QR ,Wang, ZQ ,Yan, Z ,et al. Tectonic affinity and timing of two types of amphibolites within the Qinling Group, north Qinling orogenic belt[J]. ACTA PETROLOGICA SINICA,2009,25(9):2177-2194.
APA	Yan, QR .,Wang, ZQ .,Yan, Z .,Chen, JL .,Xiang, ZJ .,...&Zhang, HY .(2009).Tectonic affinity and timing of two types of amphibolites within the Qinling Group, north Qinling orogenic belt.ACTA PETROLOGICA SINICA,25(9),2177-2194.
MLA	Yan, QR ,et al."Tectonic affinity and timing of two types of amphibolites within the Qinling Group, north Qinling orogenic belt".ACTA PETROLOGICA SINICA 25.9(2009):2177-2194.