Late Cretaceous crustal growth in the Gangdese area, southern Tibet: Petrological and Sr-Nd-Hf-O isotopic evidence from Zhengga diorite-gabbro

doi:10.1016/j.chemgeo.2013.04.005

	Late Cretaceous crustal growth in the Gangdese area, southern Tibet: Petrological and Sr-Nd-Hf-O isotopic evidence from Zhengga diorite-gabbro
	Ma, Lin 1,2; Wang, Qiang 1; Wyman, Derek A.3; Jiang, Zi-Qi 1,2; Yang, Jin-Hui 4; Li, Qiu-Li 4; Gou, Guo-Ning 1,2; Guo, Hai-Feng 1,2
刊名	CHEMICAL GEOLOGY
	2013-06-26
卷号	349 页码:54-70
关键词	Gabbro Metasomatized lithospheric mantle Anorthosite Underplating Crustal growth Southern Tibet
ISSN号	0009-2541
DOI	10.1016/j.chemgeo.2013.04.005
文献子类	Article
英文摘要	Recent studies of Gangdese granitic magmatism demonstrate a mantle contribution to crustal growth in southern Tibet during the Jurassic-Early Eocene. However, the specific mechanism for adding such juvenile crust has been disputed owing to a lack of reliable evidence for contemporaneous deep mantle geodynamic processes. Here, we report on the Zhengga diorite-gabbro suite from the Gangdese area. They consist of plagioclase (labra-dorite and anorthite), amphibole, clinopyroxene, biotite and minor magnetite, epidote, zircon and apatite. LA-ICP-MS zircon U-Pb dating for two samples gives a ca. 94 Ma age for the Zhengga intrusive rocks, i.e., the Late Cretaceous. Apart from one high-SiO2 (52.2 wt.%) diorite sample with slightly high K2O (1.72 wt.%) and initial Sr-87/Sr-86 (0.7068) and low epsilon(Nd)(t) (-5.6) values, the gabbro samples are geochemically characterized by low SiO2 (39.8-50.1 wt.%) and K2O (0.3-1.1 wt.%), strongly negative Nb-Ta and positive Sr anomalies, and uniform initial Sr-87/Sr-86 (0.7043-0.7048). The gabbros can be divided into two groups: Group I gabbros with relatively low total rare earth element (REE), Rb and SiO2 contents and positive Eu anomalies, and Group II gabbros with slightly higher total REE, Rb and SiO2 contents and negative Eu anomalies. The Group I gabbros have epsilon(Nd)(t) (+ 1.7 to +4.1), and zircon epsilon(Hf)(t) (+ 6.5 to +11.1) and delta O-18 (5.89 to 724 parts per thousand) values, which are slightly different to those of the Group II gabbros (- 02 to + 2.0, +2.9 to + 6.5 and 624 to 7.05 parts per thousand). Trace element compositions of amphibole and clinopyroxene grains suggest that the Zhengga mafic magmas contained a significant fluid-transported component, probably released from subducted oceanic lithosphere. We suggest that the parental magmas of the Zhengga gabbros were generated by the hydrous partial melting of lithospheric mantle metasomatized by sediment melts/fluids. The Group 1 gabbros were likely generated by the fractional crystallization of olivine or clinopyroxene from such parental magmas, with insignificant crustal contamination, whereas the Group 11 gabbros were probably produced by assimilation and fractional crystallization (AFC) processes from mafic magmas that were geochemically similar to the Group 1 gabbros. Pre-collisional underplating of mantle-derived mafic magmas likely played an important role in crustal growth and supplied the source materials for some late Late Cretaceous-Cenozoic granitoids of the Gangdese batholiths. This study also demonstrates that the hydrous partial melting of mantle wedge triggered by the dehydration in a subduction setting has a capacity to create significant volumes of juvenile continental crust. (C) 2013 Elsevier B.V. All rights reserved.
WOS关键词	ZIRCON U-PB ; LINZIZONG VOLCANIC SUCCESSIONS ; ISUA GREENSTONE-BELT ; OCEAN MANTLE DOMAIN ; CONTINENTAL-CRUST ; MAGMATIC EPIDOTE ; TRACE-ELEMENTS ; GEOCHEMICAL CHARACTERISTICS ; TECTONIC EVOLUTION ; SOUTHEASTERN TIBET
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000321601800005
资助机构	Chinese Academy of Sciences(XDB03010600) ; Chinese Academy of Sciences(XDB03010600) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; 41073029 ; 41073029 ; 41121002) ; 41121002) ; Chinese Academy of Sciences(XDB03010600) ; Chinese Academy of Sciences(XDB03010600) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; 41073029 ; 41073029 ; 41121002) ; 41121002) ; Chinese Academy of Sciences(XDB03010600) ; Chinese Academy of Sciences(XDB03010600) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; 41073029 ; 41073029 ; 41121002) ; 41121002) ; Chinese Academy of Sciences(XDB03010600) ; Chinese Academy of Sciences(XDB03010600) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences(Y234021001) ; 41073029 ; 41073029 ; 41121002) ; 41121002)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/87010]
专题	中国科学院地质与地球物理研究所
通讯作者	Wang, Qiang
作者单位	1.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Guangdong, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Univ Sydney, Sch Geosci, Sydney, NSW 2006, Australia 4.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Ma, Lin,Wang, Qiang,Wyman, Derek A.,et al. Late Cretaceous crustal growth in the Gangdese area, southern Tibet: Petrological and Sr-Nd-Hf-O isotopic evidence from Zhengga diorite-gabbro[J]. CHEMICAL GEOLOGY,2013,349:54-70.
APA	Ma, Lin.,Wang, Qiang.,Wyman, Derek A..,Jiang, Zi-Qi.,Yang, Jin-Hui.,...&Guo, Hai-Feng.(2013).Late Cretaceous crustal growth in the Gangdese area, southern Tibet: Petrological and Sr-Nd-Hf-O isotopic evidence from Zhengga diorite-gabbro.CHEMICAL GEOLOGY,349,54-70.
MLA	Ma, Lin,et al."Late Cretaceous crustal growth in the Gangdese area, southern Tibet: Petrological and Sr-Nd-Hf-O isotopic evidence from Zhengga diorite-gabbro".CHEMICAL GEOLOGY 349(2013):54-70.