Late Early Cretaceous adakitic granitoids and associated magnesian and potassium-rich mafic enclaves and dikes in the Tunchang-Fengmu area, Hainan Province (South China): Partial melting of lower crust and mantle, and magma hybridization

doi:10.1016/j.chemgeo.2012.04.029

	Late Early Cretaceous adakitic granitoids and associated magnesian and potassium-rich mafic enclaves and dikes in the Tunchang-Fengmu area, Hainan Province (South China): Partial melting of lower crust and mantle, and magma hybridization
	Wang, Qiang 1; Li, Xian-Hua 2; Jia, Xiao-Hui 1,6; Wyman, Derek 3; Tang, Gong-Jian 1; Li, Zheng-Xiang 4,5; Ma, Lin 1; Yang, Yue-Heng 2; Jiang, Zi-Qi 1; Gou, Guo-Ning 1
刊名	CHEMICAL GEOLOGY
	2012-10-18
卷号	328 页码:222-243
关键词	Adakites Shoshonites Enclaves Magma mixing Underplating South China
ISSN号	0009-2541
DOI	10.1016/j.chemgeo.2012.04.029
文献子类	Article
英文摘要	This paper reports on a rare magmatic suite of adakitic rocks and associated magnesian and potassium-rich magmatic enclaves and dikes, which occur in the Tunchang-Fengmu area, Hainan Island (Southeast China). LA-ICP-MS zircon U-Pb age data show that they were generated in the late Early Cretaceous (similar to 107 Ma). The adakitic rocks, consisting mainly of granodiorites and biotite granites, are high-K cal-calkaline and have low Mg-# values (0.27-0.50). They are geochemically similar to slab-derived adakites, e.g., with high SiO2, Al2O3, Sr, Sr/Y and La/Yb values, low Y and Yb contents, and negligible Eu and positive Sr anomalies. They also have relatively uniform (Sr-87/Sr-86); (0.7086-0.7096), (Pb-206/Pb-204)(i) (18.50-18.61), (Pb-207/Pb-204)(i) (15.56-15.64) and (Pb-208/Pb-204)(i) (38.17-38.44) isotope ratios, with slightly variable epsilon(Nd)(t) (-3.85 to -6.55) and zircon in situ epsilon(Hf)(t) (-4.7 to +1.7) values. The mafic enclaves and dikes display disequilibrium textures (e.g., multiple-zoned clinopyroxene with low-MgO rims in contact with perthite and quartz microcrystals). They are high-K calc-alkaline and shoshonitic, and all but one sample have high Mg-# (0.63-0.72) values. These mafic rocks are characterized by light rare earth element enrichment and heavy rare earth element (REE) depletion, negligible Eu and Sr and positive Pb anomalies, and Nb and Ta depletion. They have slightly more variable initial Sr-87/Sr-86 isotope ratios (0.7064-0.7086), epsilon(Nd)(t) (-5.1 to +0.1) values. and (Pb-206/Pb-204)(i) (18.35-18.50), (Pb-207/Pb-204)(i) (15.45-15.59) and (Pb-208/Pb-204)(i) (38.18-38.70) ratios. One mafic dike sample has zircon in situ epsilon(Hf)(t) values (-4.94 to -2.42) similar to those of adakitic rocks (-4.7 to +1.7) in the area. We suggest that the adakitic rocks were most likely generated by partial melting of newly underplated basaltic lower crust with arc-like geochemical characteristics, and the primitive compositions of the mafic enclaves and dikes likely originated from lithospheric + asthenospheric mantle sources meta-somatized by subducted oceanic sediments or a relatively juvenile lithospheric mantle source. Mantle-derived primitive magmas likely underwent mixing at depth with minor crustally-derived felsic magmas before being injected into the adakitic magma chamber. Such injections may have broken up the magma into discrete globules and convective motion distributed the enclaves through the adakitic host. Asthenosphere upwelling due to the roll-back of the subducted Paleo-Pacific plate likely triggered the coeval late Early Cretaceous crust- and mantle-derived magmatism, resulting in the magma hybridization observed on Hainan Island. (C) 2012 Elsevier B.V. All rights reserved.
WOS关键词	LOWER CONTINENTAL-CRUST ; U-PB ZIRCON ; LITHOSPHERE-ASTHENOSPHERE INTERACTION ; UNDERPLATED BASALTIC CRUST ; THICKENED LOWER CRUST ; CU-AU MINERALIZATION ; SLAB-DERIVED MELTS ; SE CHINA ; INTRUSIVE ROCKS ; VOLCANIC-ROCKS
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000310124900014
资助机构	Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; 41073029 ; 41073029 ; 41121002) ; 41121002) ; Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; 41073029 ; 41073029 ; 41121002) ; 41121002) ; Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; 41073029 ; 41073029 ; 41121002) ; 41121002) ; Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; Knowledge Innovation Program of Chinese Academy of Sciences(KZCX1-YW-15-2) ; National Natural Science Foundation of China(41025006 ; National Natural Science Foundation of China(41025006 ; 41073029 ; 41073029 ; 41121002) ; 41121002)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84504]
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, State Key Lab Isotope Geochem, Guangzhou Inst Geochem, Guangzhou 510640, Guangdong, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 3.Univ Sydney, Sch Geosci, Sydney, NSW 2006, Australia 4.Curtin Univ Technol, ARC Ctr Excellence Core Crust Fluid Syst CCFS, Perth, WA 6845, Australia 5.Curtin Univ Technol, Inst Geosci Res TIGeR, Dept Appl Geol, Perth, WA 6845, Australia 6.Wuhan Inst Geol & Mineral Resources, Wuhan 430223, Peoples R China
推荐引用方式 GB/T 7714	Wang, Qiang,Li, Xian-Hua,Jia, Xiao-Hui,et al. Late Early Cretaceous adakitic granitoids and associated magnesian and potassium-rich mafic enclaves and dikes in the Tunchang-Fengmu area, Hainan Province (South China): Partial melting of lower crust and mantle, and magma hybridization[J]. CHEMICAL GEOLOGY,2012,328:222-243.
APA	Wang, Qiang.,Li, Xian-Hua.,Jia, Xiao-Hui.,Wyman, Derek.,Tang, Gong-Jian.,...&Gou, Guo-Ning.(2012).Late Early Cretaceous adakitic granitoids and associated magnesian and potassium-rich mafic enclaves and dikes in the Tunchang-Fengmu area, Hainan Province (South China): Partial melting of lower crust and mantle, and magma hybridization.CHEMICAL GEOLOGY,328,222-243.
MLA	Wang, Qiang,et al."Late Early Cretaceous adakitic granitoids and associated magnesian and potassium-rich mafic enclaves and dikes in the Tunchang-Fengmu area, Hainan Province (South China): Partial melting of lower crust and mantle, and magma hybridization".CHEMICAL GEOLOGY 328(2012):222-243.