Petrogenesis of volcanic rocks from Early Devonian Marasu Formation, West Junggar

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	Petrogenesis of volcanic rocks from Early Devonian Marasu Formation, West Junggar
	Li Ping 1; Wang HongLiang ; Xu XueYi 1; Chen JunLu ; Guo Lei ; Xi RenGang
刊名	ACTA PETROLOGICA SINICA
	2014
卷号	30 期号:12 页码:3553-3568
关键词	Marasu Formation Basic- and intermediate-volcanic rocks Geochemical features Back-arc basin West Junngar
ISSN号	1000-0569
英文摘要	Volcanic rocks from Marasu Formation of Early Devonian, occurred in northern West Junngar, are sodium-rich and Low-K tholeiitic series, these basaltic andesites and basalts on the north side of Xiemistai fault are generally distributed in the outcrops of pyroclastic rocks intermittently. The Hark diagrams of Me versus major and trace elements and plots of Th-Th/Nd suggest these basic- and intermediate-lavas were not formed only by the comagmatic evolution. The basaltic andesites in this study are characterized by enrichments in large ion lithophile elements (LILE) and depleted in high field-strength elements (HFSE), low Th contents and high Hf/Th and (Nb/Th)(PM) ratios, all of which show the typical geochemical features of subduction zones. The basalts have nearly flat REE patterns, high Th contents and low Hf/Th and ( Nb/Th) pm ratios, similar to the geochemical features of MORB. Although they also show various enrichments in LILE and depleted in HFSE, the high La/Nb ratios suggest that they are related to the added crust or subducting materials. Besides, some geotectonic discrimination diagrams also can reflect they are MORB-like basalts. HFSE/HFSE ratios (e. g. Zr/Nb, Hf/Ta) of both are similar to that of mid-oceanic ridge basalts, which should be the partial melting products of MORB sources. The primitive mantle normalized ratios of La/Yb and Gd/Yb suggest the basaltic andesites were originated from garnet-bearing or spinel-garnet mantle peridotites with subducting sediments or crustal materials added, and MORB-like basalts were formed by the partial melting of the spinel-bearing mantle peridotites. Several lines of evidence suggest that the Marasu volcanic rocks in northern West Junggar, with both geochemical characteristics of island arc and MORB-like volcanics, may be the magmatic records of back-arc spreading in tectonic collage.
学科主题	火成岩岩石学
WOS关键词	PALEOZOIC TECTONIC EVOLUTION ; SUBDUCTION-RELATED MAGMATISM ; ASIAN OROGENIC BELT ; NW-CHINA ; TRACE-ELEMENT ; GEOCHEMICAL CHARACTERISTICS ; NORTHERN XINJIANG ; RIDGE SUBDUCTION ; CRUSTAL CONTAMINATION ; CONTINENTAL-CRUST
WOS研究方向	Geology
语种	中文
出版者	SCIENCE PRESS
WOS记录号	WOS:000347270400007
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40272]
专题	中国地质调查局西安地质调查中心
作者单位	1.CGS, Xian Ctr Geol Survey, Xian 710054, Peoples R China 2.MLR Key Lab Study Focused Magmatism & Giant Depos, Xian 710054, Peoples R China
推荐引用方式 GB/T 7714	Li Ping,Wang HongLiang,Xu XueYi,et al. Petrogenesis of volcanic rocks from Early Devonian Marasu Formation, West Junggar[J]. ACTA PETROLOGICA SINICA,2014,30(12):3553-3568.
APA	Li Ping,Wang HongLiang,Xu XueYi,Chen JunLu,Guo Lei,&Xi RenGang.(2014).Petrogenesis of volcanic rocks from Early Devonian Marasu Formation, West Junggar.ACTA PETROLOGICA SINICA,30(12),3553-3568.
MLA	Li Ping,et al."Petrogenesis of volcanic rocks from Early Devonian Marasu Formation, West Junggar".ACTA PETROLOGICA SINICA 30.12(2014):3553-3568.