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
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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. |
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