| 青藏高原东北缘祁连山三叠系砂岩碎屑锆石U-Pb定年及其物源分析 |
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| 引用本文： | 吴龙,柳长峰,刘文灿,张宏远.青藏高原东北缘祁连山三叠系砂岩碎屑锆石U-Pb定年及其物源分析[J].现代地质,2021,35(5):1178-1193. |
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| 作者姓名： | 吴龙 柳长峰 刘文灿 张宏远 |
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| 作者单位： | 1.湖北省地质调查院,湖北 武汉 4300342.中国地质大学(北京) 海洋学院,北京 1000833.中国地质大学(北京) 地球科学与资源学院,北京 100083 |
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| 基金项目： | 中国地质调查局地质调查专题项目“新疆且末县阿克苏河一带构造变形特征及动力学机制研究”(D216080);中国地质调查局地质调查项目(1212011121188) |
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| 摘 要： | 三叠系沉积物广泛覆盖青藏高原东北缘,其中松潘—甘孜地区三叠系的沉积物得到了较系统的研究,但是青藏高原北缘的祁连山三叠系盆地的研究却较为缺乏。为了丰富相关研究和揭示区域构造演化的特点,通过古水流方向统计、砂岩中碎屑矿物统计和碎屑锆石U-Pb测年等方法对祁连山三叠纪盆地物源进行系统研究。结果表明,祁连山三叠系盆地的古流向主要有南东向、正南向、南西向,物源来自岩浆弧和大规模褶皱造山作用的混合区。祁连山三叠系砂岩中的碎屑锆石的年龄谱主要峰值集中在250~290 Ma、360~460 Ma、1 600~2 000 Ma和2 200~2 600 Ma这4个年龄段。通过对比分析华北板块、华南板块中和秦祁昆中央造山带中岩浆锆石年龄谱特征可知:1 600~2 000 Ma和2 200~2 600 Ma年龄段的锆石来自华北板块,360~460 Ma年龄段的锆石来自北祁连造山带,250~290 Ma年龄段的锆石来自东昆仑的火山岛弧。此外,600~1 000 Ma年龄段锆石很少,这些锆石来自扬子板块,表明在三叠纪扬子克拉通和华北克拉通发生碰撞形成了秦岭造山带,阻断了来自扬子克拉通的物源。
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| 关 键 词： | 祁连山 三叠系砂岩 碎屑锆石U-Pb定年 物源分析 |
| 收稿时间： | 2020-06-30 |
| 修稿时间： | 2021-08-30 |
Detrital Zircon U-Pb Dating and Provenance Analysis for the Triassic Sandstone in Qilianshan Orogen,NE Margin of Tibetan Plateau |
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| WU Long,LIU Changfeng,LIU Wencan,ZHANG Hongyuan.Detrital Zircon U-Pb Dating and Provenance Analysis for the Triassic Sandstone in Qilianshan Orogen,NE Margin of Tibetan Plateau[J].Geoscience——Journal of Graduate School,China University of Geosciences,2021,35(5):1178-1193. |
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| Authors: | WU Long LIU Changfeng LIU Wencan ZHANG Hongyuan |
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| Institution: | 1. Hubei Geological Survey, Wuhan, Hubei 430034,China2. School of Ocean Sciences, China University of Geosciences, Beijing 100083,China3. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China |
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| Abstract: | Triassic detrital sediments occurring in the northern margin of the Tibetan Plateau, which has been well studied in the Songpan-Ganzi terrane, yet the Triassic basin in the Qilianshan remain poorly understood. In this contribution, we integrated stratigraphy, sedimentology, zircon U-Pb dating on the Triassic sandstones in the Qilianshan to decipher their complex regional tectonic evolution. The results show that the ages of detrital zircons concentrate at four populations in 250-290 Ma,360-460 Ma,1,600-2,000 Ma,and 2,200-2,600 Ma. By comparing with the zircon age spectra in the North China Craton, South China Craton, and the Qinling-Qilian-Kunlun Central Orogenic belt, we suggest that the 1,600-2,000 Ma and 2,200-2,600 Ma zircon age populations were probably sourced from North China Craton, whereas a zircon age population of 360-460 Ma was derived from the North Qilian Orogenic Belt. The 250-290 Ma zircon population may have sourced from the volcanic arc of Eastern Kunlun Orogen in the south. The rare 600-1,000 Ma zircons were probably sourced from the Yangtze Block, since the Triassic North China-Yangtze collision along the Qinling Orogen may have acted as a barrier for the sediments from the Yangtze Block. |
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| Keywords: | Qilianshan Triassic sandstone detrital zircon U-Pb dating provenance analysis |
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