气候变化领域集成服务门户(CCPortal): Early Neoproterozoic accretionary assemblage in the Cathaysia Block: Geochronological, Lu-Hf isotopic and geochemical evidence from granitoid gneisses

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DOI	10.1016/j.precamres.2014.05.003
	Early Neoproterozoic accretionary assemblage in the Cathaysia Block: Geochronological, Lu-Hf isotopic and geochemical evidence from granitoid gneisses
	Wang, Yuejun; Zhang, Yuzhi; Fan, Weiming; Geng, Hongyan; Zou, Heping; Bi, Xianwu
通讯作者	Wang, YJ (通讯作者)
发表日期	2014
ISSN	0301-9268
EISSN	1872-7433
起始页码	144
结束页码	161
卷号	249
英文摘要	The South China Block (SCB) is composed of the Yangtze Block in the northwest and the Cathysia Block in the southeast. The earliest Neoproterozoic granitic rocks in the SCB are important for our understanding of the tectonic regime and location of this ancient continent in relation to the Rodinia supercontinent. However, such rocks have rarely been reported for the Cathaysia Block so far. In this study, six granitic gneisses from the Wuyi-Yunkai domain gave zircon U-Pb ages of 985-913 Ma, indicating the presence of the early Neoproterozoic granitic magmatism in the Cathaysia interior. These granitic gneisses are peraluminous with high FeOt, MgO, TiO2 and CaO/Na2O but low SiO2, Al2O3/TiOz,Al2O3/(MgO + FeOt) and Rb/Sr ratios. They show steep REE chondrite-normalized patterns with delta Eu values of 0.35-0.70. These samples have strongly negative Ba, Sr, Nb-Ta, P and Ti anomalies in primitive mantle-normalized diagrams, and epsilon Nd(t) values of -9.54 to -3.81, similar to those of the Kwangsian granitic rocks and Precambrian volcanosedimentary package in the Cathysia Block. The zircon grains with the earliest Neoproterozoic age gave epsilon Hf(t) values of -9.64 to +2.78 with the peak values at -2.5 and -7.5, and Hf model ages of 1.35-2.00 Ga with the two-peaks of 1.57 Ga and 1.75 Ga, respectively. These data suggest that the granitic gneisses originated dominantly from a binary mixing of metapelitic and metaigneous components, with insignificant input of juvenile materials. We consider that these rocks are closely related to the closure of the earliest Neoproterozoic (similar to 980 Ma) Wuyi-Yunkai back-arc basin in an accretionary continental margin setting. In combination with other data, it is proposed that the previously-defined Cathaysia block might consist of various sub-blocks separated by the arc-back-arc basin prior to the early Neoproterozoic period. The Wuyi-Yunkai arc-back-arc system was finally closed at similar to 920 Ma, significantly younger than the classical Grenvillian Orogenic event, and thus the SCB was located on the margin of the Rodinia supercontinent. (C) 2014 Elsevier B.V. All rights reserved.
关键词	S-TYPE GRANITES PB ZIRCON GEOCHRONOLOGY SOUTH CHINA BLOCK BACK-ARC BASIN U-PB YANGTZE CRATON JIANGNAN OROGEN TECTONIC ENVIRONMENT CRUSTAL EVOLUTION EAST ANTARCTICA
英文关键词	Zircon U-Pb geochronology; Lu-Hf isotopic composition; Geochemistry; Early neoproterozoic granitic gneiss; Accretionary assemblage; Cathaysia
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000339038100010
来源期刊	PRECAMBRIAN RESEARCH
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/258352
推荐引用方式 GB/T 7714	Wang, Yuejun,Zhang, Yuzhi,Fan, Weiming,et al. Early Neoproterozoic accretionary assemblage in the Cathaysia Block: Geochronological, Lu-Hf isotopic and geochemical evidence from granitoid gneisses[J]. 中国科学院青藏高原研究所,2014,249.
APA	Wang, Yuejun,Zhang, Yuzhi,Fan, Weiming,Geng, Hongyan,Zou, Heping,&Bi, Xianwu.(2014).Early Neoproterozoic accretionary assemblage in the Cathaysia Block: Geochronological, Lu-Hf isotopic and geochemical evidence from granitoid gneisses.PRECAMBRIAN RESEARCH,249.
MLA	Wang, Yuejun,et al."Early Neoproterozoic accretionary assemblage in the Cathaysia Block: Geochronological, Lu-Hf isotopic and geochemical evidence from granitoid gneisses".PRECAMBRIAN RESEARCH 249(2014).