Contrasting zircon Hf and O isotopes in the two episodes of Neoproterozoic granitoids in South China: Implications for growth and reworking of continental crust

doi:10.1016/j.lithos.2006.10.003

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	Contrasting zircon Hf and O isotopes in the two episodes of Neoproterozoic granitoids in South China: Implications for growth and reworking of continental crust
	Zheng, Yong-Fei ; Zhang, Shao-Bing ; Zhao, Zi-Fu ; Wu, Yuan-Bao ; Li, Xianhua ; Li, Zhengxiang ; Wu, Fu-Yuan
	2007-06-01
发表期刊	LITHOS
ISSN	0024-4937
卷号	96 期号:1-2 页码:127-150
文章类型	Article
摘要	The genetic links among rift magmatism, crustal growth and water-rock interaction are an important issue about mass and heat transfer between mantle and crust during supercontinent breakup. A combined study of Hf and O isotopes in zircons from Neoproterozoic granitoids in South China provides evidence for growth and reworking of juvenile and ancient crusts with different styles of water-rock interactions along rift tectonic zones. Two generations of the granitoids show contrasting features in both zircon Hf and O isotope compositions, indicating their distinct petrogenesis. The similar to 825 Ma granitoids exhibit negative epsilon(Hf)(t) values of -3.4 +/- 0.8 to -1.6 +/- 0.8 with old model Hf ages of 1.81 +/- 0.07 to 1.92 +/- 0.10 Ga, and high delta O-18 values of 8.7 to 10.4%. These indicate that the source material of granitoid magmas was derived from melting of Paleoproterozoic basement that has the Hf isotope signature similar to the enriched mantle but experienced chemical weathering process before anatexis. Reworking of ancient crust is demonstrated to occur at similar to 825 Main the orogenic collapse zone, with overprinting of subsolidus hydrothermal alteration during magma emplacement. In contrast, the 760750 Ma bimodal intrusives are characterized by positive epsilon(Hf)(t) values of 3.5 +/- 0.8 to 9.9 +/- 0.8 with young model Hf ages of 0.94 +/- 0.06 to 1.18 +/- 0.06 Ga, and both low and high delta O-18 values of 4.2 to 6.2% relative to 5.3 +/- 0.3% for the normal mantle zircon. Prompt reworking of juvenile crust is suggested to occur at similar to 750 Main the rifted tectonic zone, with occurrence of supersolidus hydrothermal alteration and local low-O-18 magmatism during supercontinent breakup. Contributions of the depleted mantle to their magma sources are contrasting in the two episodes of magmatism in association with breakup of the supercontinent Rodinia. While the change in melt source from the crust to the mantle keeps pace with the advance from continental rifting to supercontinent breakup, significant transport of both heat and material from the depleted mantle to the continental crust only occurred along the active rifting zone. In either case, the growth and reworking of continental crust are episodically associated with rift magmatism. (C) 2006 Elsevier B.V All rights reserved.
关键词	zircon Hf isotope O isotope neoproterozoic magmatism South China continental growth mantle upwelling supercontinent breakup
WOS标题词	Science & Technology ; Physical Sciences
DOI	10.1016/j.lithos.2006.10.003
关键词[WOS]	U-PB GEOCHRONOLOGY ; ULTRAHIGH-PRESSURE ECLOGITE ; MAFIC-ULTRAMAFIC ROCKS ; LU-HF ; OXYGEN ISOTOPES ; YANGTZE BLOCK ; IGNEOUS ROCKS ; DABIE OROGEN ; MANTLE PLUME ; BREAK-UP
收录类别	SCI ; ISTP
语种	英语
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:000247167300009
出版者	ELSEVIER SCIENCE BV
引用统计
文献类型	期刊论文
条目标识符	http://ir.iggcas.ac.cn/handle/132A11/68075
专题	中国科学院地质与地球物理研究所
通讯作者	Zheng, Yong-Fei
作者单位	1.Univ Sci & Technol China, Sch Earth & Space Sci, CAS, Key Lab Crust Mantle Mat & Environm, Hefei 230026, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithosphere Evolut, Beijing 100029, Peoples R China 3.China Univ Geosci, Fac Earth Sci, Wuhan 430074, Peoples R China 4.Chinese Acad Sci, Guangzhou Inst Geochem, CAS Key Lab Isotope Geochronol & Geochem, Guangzhou 510640, Peoples R China 5.Univ Western Australia, Sch Earth & Geog Sci, Tecton Special Res Ctr, Crawley, WA 6009, Australia
推荐引用方式 GB/T 7714	Zheng, Yong-Fei,Zhang, Shao-Bing,Zhao, Zi-Fu,et al. Contrasting zircon Hf and O isotopes in the two episodes of Neoproterozoic granitoids in South China: Implications for growth and reworking of continental crust[J]. LITHOS,2007,96(1-2):127-150.
APA	Zheng, Yong-Fei.,Zhang, Shao-Bing.,Zhao, Zi-Fu.,Wu, Yuan-Bao.,Li, Xianhua.,...&Wu, Fu-Yuan.(2007).Contrasting zircon Hf and O isotopes in the two episodes of Neoproterozoic granitoids in South China: Implications for growth and reworking of continental crust.LITHOS,96(1-2),127-150.
MLA	Zheng, Yong-Fei,et al."Contrasting zircon Hf and O isotopes in the two episodes of Neoproterozoic granitoids in South China: Implications for growth and reworking of continental crust".LITHOS 96.1-2(2007):127-150.