Geochronology and genesis of the bimodal volcanic rocks in Dalawuzi from the southern margin of Allay, Xinjiang

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	Geochronology and genesis of the bimodal volcanic rocks in Dalawuzi from the southern margin of Allay, Xinjiang
	Geng, XX (Geng XinXia); Chai, FM (Chai FengMei); Yang, FQ (Yang FuQuan); Zuo, WZ (Zuo WenZhe); Guo, ZL (Guo ZhengLin); Liu, F (Liu Feng); Zhang, ZX (Zhang ZhiXin)
刊名	ACTA PETROLOGICA SINICA
	2010
卷号	26 期号:10 页码:2967-2980
关键词	Bimodal volcanic rocks LA-ICP-MS zircon U-Pb dating Petrogenesis Southern margin of Altay
ISSN号	1000-0569
英文摘要	LA-ICP-MS U-Pb zircon ages are reported for meta-rhyolites in the bimodal volcanic rocks from the Altaizhen Formation in Dalawuzi area at the southern margin of Altay orogenic belt. The zircons with well-defined oscillatory zoning from meta-rhyolite sample yielded mean (206)Pb/(238)U ages of 365.6 +/- 1. 6Ma and 413. 5 +/- 2. 0Ma. The age of 365. 6 1. 6Ma represent the eruption age of the volcanic rocks of the Altaizhen Formation, which indicated that the Altaizhen Formation was formed during the Middle to Late Devonian. The age of 413. 5 2. 0Ma, which are consistent with the eruption age of the Kangbutiebao silicic volcanic rocks and Early Devonian granite, can be interpreted as an age of captured zircon from Early Devonian magmatism. Geochemically, meta-basalts are rich in titanium, alkali (especially sodium), iron, LILE and LREE and poor in magnesium. They have higher contents of HFSEs (Nb, Ta, Zr and Hf) than those of typical JAB. Meta-rhyolites are generally characterized by rich silicon, alkali, and poor magnesium. They have relatively high U, Th and rather low Ba, Sr, Ti and P. They display obvious negative anomaly of Nb, Ta and Ti, obvious enrichment of LREE, noticeable negative Eu anomalies (delta Eu =0. 21 similar to 0. 41). Basaltic and rhyolitic rocks show similar Pb isotopic data to N-MORB. On the basis of regional geological and geochemical evidences, this paper concludes that the basalt was originated from depleted asthenosphere and subducted material (subducted slab, sediments and fluids), and rhyolite resulted from thermal and the new accretion materials and mingling between basaltic magma and felsic magma. The bimodal volcanic rocks are the products of partial extension after the subduction.
学科主题	火成岩岩石学
WOS关键词	TRACE-ELEMENT GEOCHEMISTRY ; CHINESE ALTAI ; NORTHWEST CHINA ; TECTONIC EVOLUTION ; NW CHINA ; U-PB ; PETROGENESIS ; ACCRETIONARY ; MOUNTAINS ; GRANITES
WOS研究方向	Geology
语种	中文
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000284450800009
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39128]
专题	中国地质调查局
作者单位	Xinjiang Geoexplorat Bur Nonferrous Met, Altay 839000, Peoples R China
推荐引用方式 GB/T 7714	Geng, XX ,Chai, FM ,Yang, FQ ,et al. Geochronology and genesis of the bimodal volcanic rocks in Dalawuzi from the southern margin of Allay, Xinjiang[J]. ACTA PETROLOGICA SINICA,2010,26(10):2967-2980.
APA	Geng, XX .,Chai, FM .,Yang, FQ .,Zuo, WZ .,Guo, ZL .,...&Zhang, ZX .(2010).Geochronology and genesis of the bimodal volcanic rocks in Dalawuzi from the southern margin of Allay, Xinjiang.ACTA PETROLOGICA SINICA,26(10),2967-2980.
MLA	Geng, XX ,et al."Geochronology and genesis of the bimodal volcanic rocks in Dalawuzi from the southern margin of Allay, Xinjiang".ACTA PETROLOGICA SINICA 26.10(2010):2967-2980.