| 东准噶尔西缘晚古生代火山岩的锆石U-Pb年龄和Hf同位素特征及构造意义 |
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| 引用本文： | 史基安,唐相路,张顺存,张宏福,肖燕.东准噶尔西缘晚古生代火山岩的锆石U-Pb年龄和Hf同位素特征及构造意义[J].地质科学,2012,0(4):955-979. |
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| 作者姓名： | 史基安 唐相路 张顺存 张宏福 肖燕 |
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| 作者单位： | 1. 中国科学院油气资源研究重点实验室 兰州 730000;
2. 中国科学院研究生院 北京 100049;
3. 中国科学院地质与地球物理研究所 北京 100029 |
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| 摘 要： | 白碱沟和帐篷沟剖面位于东准噶尔西缘,出露有大量古生代火山岩,是研究东准噶尔古生代火山岩及构造演化的有利区域.本文利用LA-MC-ICP-MS锆石U-Pb定年法和Hf同位素系统对该区中的玄武岩、玄武质安山岩、流纹岩、角斑岩以及少量的凝灰岩和正长斑岩进行了地质年代学研究,认为它们形成于早泥盆世至晚石炭世之间(400～307...
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| 关 键 词： | 中亚造山带 东准噶尔 锆石U-Pb定年 Hf同位素 年轻地壳 岛弧 陆壳增生 |
| 收稿时间： | 2012-06-02 |
| 修稿时间： | 2012-06-02; |
Zircon U-Pb age and Hf isotopic systematics of Late Paleozoic volcanic from the western margin of east Junggar and tectonic implication |
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| Shi Ji'an,Tang Xianglu,Zhang Shuncun,Zhang Hongfu,Xiao Yan.Zircon U-Pb age and Hf isotopic systematics of Late Paleozoic volcanic from the western margin of east Junggar and tectonic implication[J].Chinese Journal of Geology,2012,0(4):955-979. |
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| Authors: | Shi Ji'an Tang Xianglu Zhang Shuncun Zhang Hongfu Xiao Yan |
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| Institution: | 1. Key Laboratory of Petroleum Resources Research,Institute of Geology and Geophysics,Chinese Academy of Sciences,Lanzhou 730000;
2. Graduate University of Chinese Academy of Sciences,Beijing 100049;
3. Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029 |
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| Abstract: | Two sections,namely Baijiangou and Zhangpenggo,in the western margin of east Junggar,where expose a large number of Paleozoic volcanic rocks,are the favorable areas to study the tectonic evolution of the east Junggar.LA-MC-ICP-MS zircon U-Pb dating and Hf isotopic systematics study of igneous rocks(basalt,basaltic andesite,rhyolite and keratophyre with minor tuff and syenite-porphyry),using geochrony technology,suggests that they were formed during Early Devonian to Late Carboniferous(400～307 Ma).Basalts and basaltic andesites are more likely output as dikes,and they display age-range from 435 Ma to 300 Ma and show positive εHf(t) values(+0.7～+15.4),which suggests that the east Junggar terrane is controled by juvenile crust and that the Precambrian crystalline rocks must be very limited,if there is any.The Zhangpenggou rhyolite and keratophyre,zircon U-Pb ages of 332 Ma and 336 Ma respectively,were formed in a volcanic arc environment or a environment which was mixed with part of island arc.The Baijiangou syenite-porphyries with positive εHf(t) values in Late Carboniferous(307 Ma and 315 Ma)indicate a vertical accretion of crustal materials.The Baijiangou rhyolites which show positive εHf(t)values and zircon U-Pb ages of 315 Ma and 323 Ma suggests a lateral accretion of crustal materials.Therefore,the east Junggar is mainly accretionary prism undering extensional settings of post-collisional period,and it's considered today to be a Paleozoic Mariana-type intra-oceanic island arc. |
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| Keywords: | Central Asian orogenic belt East Junggar Zircon U-Pb dating Hf isotopic Juvenile crust Island arc Continental growth |
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