Amalgamation between the Yangtze and Cathaysia Blocks in South China: Constraints from SHRIMP U-Pb zircon ages, geochemistry and Nd-Hf isotopes of the Shuangxiwu volcanic rocks

doi:10.1016/j.precamres.2009.07.004

	Amalgamation between the Yangtze and Cathaysia Blocks in South China: Constraints from SHRIMP U-Pb zircon ages, geochemistry and Nd-Hf isotopes of the Shuangxiwu volcanic rocks
	Li, Xian-Hua 1,2; Li, Wu-Xian 3; Li, Zheng-Xiang 4; Lo, Ching-Hua 2; Wang, Jian 5; Ye, Mei-Fang 3; Yang, Yue-Heng 1
刊名	PRECAMBRIAN RESEARCH
	2009-10-01
卷号	174 期号:1-2 页码:117-128
关键词	Volcanic arc U-Pb zircon age Geochemistry Nd-Hf isotopes South China Neoproterozoic
ISSN号	0301-9268
DOI	10.1016/j.precamres.2009.07.004
文献子类	Article
英文摘要	South China was formed through the amalgamation of the Yangtze Block with the Cathaysia Block, but the timing of this amalgamation is controversial, ranging from Mesoproterozoic to Mesozoic. We report here SHRIMP U-Pb zircon ages, geochemistry and Nd-Hf isotopes of the Shuangxiwu Group volcanic rocks from the southeastern Yangtze Block. These rocks were strongly deformed, metamorphosed to greenschist-facies, intruded by 849 +/- 7 Ma dolerites, and unconformably overlain by Neoproterozoic rift successions of no older than ca. 820 Ma. The Beiwu and Zhangcun volcanic rocks from the middle and uppermost Shuangxiwu Group were dated at 926 +/- 15 Ma and 891 +/- 12 Ma, respectively. All the studied rocks are characterized by highly positive epsilon Nd(T) (5.4-8.7) and epsilon Hf(T) (11.0-15.3) values. The Pingshui basaltic and andesitic rocks from the lower Shuangxiwu Group, which were previously dated at ca. 970 Ma, are high in Al(2)O(3) (15-20%) but low in MgO (<8%), and are characterized by enrichments in Th and LREE but depletions in Nb, Ta, Zr, Hf and Ti, broadly similar to high-Al basaltic rocks in many volcanic arcs. The Beiwu andesitic to rhyolitic rocks have higher MgO than the experimental melts of basaltic rocks, and their Al(2)O(3) content decreases with increasing SiO(2), similar to the regional coeval tonalites and granodiorites, suggesting their formation by crystal fractionation of basaltic parent magma. The Zhangcun volcanic rocks are high in SiO(2) (mostly >69%), low in MgO (0.35-1.2%), and have nearly constant Al(2)O(3) contents of 14-15% and relatively uniform trace element concentrations. They were generated by remelting of juvenile mafic to intermediate arc rocks. Overall, the Shuangxiwu Group volcanic rocks and associated intrusive tonalites and granodiorites constitute a typical calc-alkaline magmatic assemblage of a 970-890 Ma active continental margin. These results and the 849 +/- 7 Ma zircon U-Pb age for the undeformed doleritic dikes intruding the Shuangxiwu Group suggest that the tectonic regime of the study region transformed from plate convergence to intracontinental rifting in the time period between ca. 890 Ma and ca. 850 Ma. Previously reported 1.04-0.94 Ga metamorphic and deformation ages from the nearby Tianli Schists and evidence for the final closure of the back-arc basin at ca. 880 Ma (ophilitic obduction at Xiwan), further suggest that the amalgamation between the Yangtze and Cathaysia Blocks, likely through "soft docking" at the eastern segment of the Sibao orogen, was completed at ca. 880 Ma or soon after. (C) 2009 Elsevier B.V. All rights reserved.
WOS关键词	NEOPROTEROZOIC TECTONIC EVOLUTION ; CONTINENTAL FLOOD BASALTS ; HIGH-ALUMINA BASALTS ; SM-ND ; JIANGNAN OROGEN ; WESTERN MARGIN ; MANTLE PLUME ; ALEUTIAN ARC ; SOUTHEASTERN CHINA ; NORTHERN GUANGXI
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000271362800007
资助机构	NSFC(40721063 ; NSFC(40721063 ; ARC Discovery Project(DP0770228) ; ARC Discovery Project(DP0770228) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; 40573016) ; 40573016) ; NSFC(40721063 ; NSFC(40721063 ; ARC Discovery Project(DP0770228) ; ARC Discovery Project(DP0770228) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; 40573016) ; 40573016) ; NSFC(40721063 ; NSFC(40721063 ; ARC Discovery Project(DP0770228) ; ARC Discovery Project(DP0770228) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; 40573016) ; 40573016) ; NSFC(40721063 ; NSFC(40721063 ; ARC Discovery Project(DP0770228) ; ARC Discovery Project(DP0770228) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; TIGeR (The Institute for Geoscience Research)(IGCP440) ; 40573016) ; 40573016)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/70314]
专题	中国科学院地质与地球物理研究所
通讯作者	Li, Xian-Hua
作者单位	1.Chinese Acad Sci, State Key Lab Lithospher Evolut, Inst Geol & Geophys, Beijing 100027, Peoples R China 2.Natl Taiwan Univ, Dept Geosci, Taipei 106, Taiwan 3.Chinese Acad Sci, Guangzhou Inst Geochem, Key Lab Isotope Geochronol & Geochem, Guangzhou 510640, Guangdong, Peoples R China 4.Curtin Univ Technol, Inst Geosci Res, Dept Appl Geol, Perth, WA 6845, Australia 5.Chengdu Inst Geol & Mineral Resources, Chengdu 610082, Peoples R China
推荐引用方式 GB/T 7714	Li, Xian-Hua,Li, Wu-Xian,Li, Zheng-Xiang,et al. Amalgamation between the Yangtze and Cathaysia Blocks in South China: Constraints from SHRIMP U-Pb zircon ages, geochemistry and Nd-Hf isotopes of the Shuangxiwu volcanic rocks[J]. PRECAMBRIAN RESEARCH,2009,174(1-2):117-128.
APA	Li, Xian-Hua.,Li, Wu-Xian.,Li, Zheng-Xiang.,Lo, Ching-Hua.,Wang, Jian.,...&Yang, Yue-Heng.(2009).Amalgamation between the Yangtze and Cathaysia Blocks in South China: Constraints from SHRIMP U-Pb zircon ages, geochemistry and Nd-Hf isotopes of the Shuangxiwu volcanic rocks.PRECAMBRIAN RESEARCH,174(1-2),117-128.
MLA	Li, Xian-Hua,et al."Amalgamation between the Yangtze and Cathaysia Blocks in South China: Constraints from SHRIMP U-Pb zircon ages, geochemistry and Nd-Hf isotopes of the Shuangxiwu volcanic rocks".PRECAMBRIAN RESEARCH 174.1-2(2009):117-128.