Geochronology and Genesis of the Bimodal Volcanic Rocks in Dalawuzi from the Southern Margin of Altay, Xinjiang
详细信息
- 责任者：Geng Xinxia (Institute of Mineral Resources ; Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Chai Fengmei
- 刊名：Acta Petrologica Sinica
- 出版年：2010
- 卷期：26(10)
- 关键词：双峰式火山岩 ; bimodal volcanic rocks ; 铀—铅计时 ; U-Pb dating ; 新疆 ; Xinjiang
- 页码：p.2967-2980
- 图表：4 illus., 3 tables, 83 refs.
- 分类号：0801
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
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 206Pb/238U ages of 365.6±1.6 Ma and 413.5±2.0 Ma. The age of 365.6±1.6 Ma 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. This paper concludes that the basalt was originated from depleted asthenosphere and subducted material, 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.
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