Petrogenesis of Carboniferous adakites and Nb-enriched arc basalts in the Alataw area, northern Tianshan Range (western China): Implications for Phanerozoic crustal growth in the Central Asia orogenic belt

doi:10.1016/j.chemgeo.2006.08.013

	Petrogenesis of Carboniferous adakites and Nb-enriched arc basalts in the Alataw area, northern Tianshan Range (western China): Implications for Phanerozoic crustal growth in the Central Asia orogenic belt
	Wang, Qiang ; Wyman, Derek A.; Zhao, Zhen-Hua ; Xu, Ji-Feng ; Bai, Zheng-Hua ; Xiong, Xiao-Lin ; Dai, Tong-Mo ; Li, Chao-Feng ; Chu, Zhu-Yin
刊名	CHEMICAL GEOLOGY
	2007-01-15
卷号	236 期号:1-2 页码:42-64
关键词	adakite Nb-enriched basalts slab melting mantle metasomatism crust growth Tianshan
ISSN号	0009-2541
DOI	10.1016/j.chemgeo.2006.08.013
文献子类	Review
英文摘要	Carboniferous volcanic rocks in the Alataw area, Northern Tianshan Range (Xinjiang), consist of early Carboniferous (ca. 320 Ma) adakites and Nb-enriched arc basalts and basaltic andesites (NEBs), and late Carboniferous (ca. 306-310 Ma) mainly high-K calc-alkaline andesites, dacites and rhyolites. The adakites are calc-alkaline, and characterized by high Na(2)O/K(2)O (1.52-3.32) ratios, negligible to positive Eu anomalies, strong depletion of heavy rare earth elements (e.g., Yb = 0.74-1.47 ppm) and Y (6.7-14.9 ppm), positive Sr and Ba but negative Nb and Ti anomalies, and relatively constant epsilon(Nd)(T) values (+3.4-+6.6) and ((87)Sr/(16)Sr)(i) ratios (0.7035-0.7042). Some andesitic and dacitic adakite samples exhibit high MgO contents similar to magnesian andesites. The NEBs are sodium-rich (Na(2)O/K(2)O=2.03-8.06), and differ from the vast majority of arc basalts in their higher Nb, Zr, TiO(2) and P(2)O(5) contents and Nb/Th, Nb/La and Nb/U ratios, and minor negative to positive anomalies in Ba, Nb, Sr, Zr and Ti. They have the highest epsilon(Nd)(T) values (+6.4-+11.6) but varying ((87)Sr/(86)Sr)(i) ratios (0.7007-0.7063). The high-K calc-alkaline suite is similar to typical 'normal' arc volcanic rocks in terms of moderately fractionated rare earth abundance and distinctly negative Eu, Nb, Sr and Ti anomalies. They have epsilon(Nd)(T) values (+1.2-+6.4) and ((17)Sr/(116)Sr)(i) ratios (0.7018-0.7059). Geochemically, they are similar to coeval I-type granitoids in the Alataw area. Given the presence of early Carboniferous ophiolites in the Northern Tianshan Range, and the isotopically inappropriate compositions of Proterozoic metamorphic basement in the Alataw area, we argue that the Alataw adakites were most probably related to the melting of young subducted crust of the Northern Tianshan Ocean. The NEBs likely originated from mantle wedge peridotites metasomatized by adakites and minor slab-derived fluids. The later high-K calc alkaline suite was generated by AFC processes that acted on melts derived from a mantle wedge metasomatized by hydrous fluids. The larger range of isotopic compositions exhibited by both the NEB and high-K suite, relative to the adakites, suggests that the mantle wedge was heterogeneous prior to slab- or fluid-mediated metasomatism.
WOS关键词	ND-PB ISOTOPE ; STRENGTH ELEMENT ENRICHMENT ; ARCHEAN SUBDUCTION ZONE ; LOWER CONTINENTAL-CRUST ; A-TYPE GRANITES ; VOLCANIC-ROCKS ; TECTONIC IMPLICATIONS ; EASTERN TIANSHAN ; INTRUSIVE ROCKS ; NORTHWEST CHINA
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000243678100004
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/67772]
专题	中国科学院地质与地球物理研究所
通讯作者	Wyman, Derek A.
作者单位	1.Univ Sydney, Sch Geosci, Div Geol & Geophys, Sydney, NSW 2006, Australia 2.Chinese Acad Sci, Key Lab Isotope Geochronol & Geochem, Guangzhou Inst Geochem, Guangzhou 510640, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Wang, Qiang,Wyman, Derek A.,Zhao, Zhen-Hua,et al. Petrogenesis of Carboniferous adakites and Nb-enriched arc basalts in the Alataw area, northern Tianshan Range (western China): Implications for Phanerozoic crustal growth in the Central Asia orogenic belt[J]. CHEMICAL GEOLOGY,2007,236(1-2):42-64.
APA	Wang, Qiang.,Wyman, Derek A..,Zhao, Zhen-Hua.,Xu, Ji-Feng.,Bai, Zheng-Hua.,...&Chu, Zhu-Yin.(2007).Petrogenesis of Carboniferous adakites and Nb-enriched arc basalts in the Alataw area, northern Tianshan Range (western China): Implications for Phanerozoic crustal growth in the Central Asia orogenic belt.CHEMICAL GEOLOGY,236(1-2),42-64.
MLA	Wang, Qiang,et al."Petrogenesis of Carboniferous adakites and Nb-enriched arc basalts in the Alataw area, northern Tianshan Range (western China): Implications for Phanerozoic crustal growth in the Central Asia orogenic belt".CHEMICAL GEOLOGY 236.1-2(2007):42-64.