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| 柴达木西部第三系砂岩碎屑锆石LA-ICP-MS年龄对阿尔金造山带隆升的制约 | |
| 引用本文： | 周海,陈亮,孙勇,第五春荣,彭德华,尹成明,雷川.柴达木西部第三系砂岩碎屑锆石LA-ICP-MS年龄对阿尔金造山带隆升的制约[J].地质学报,2012,86(6):906-922. |
| 作者姓名： | 周海 陈亮 孙勇 第五春荣 彭德华 尹成明 雷川 |
| 作者单位： | 1. 大陆动力学国家重点实验室,西北大学地质学系,西安,710069 2. 中国石油青海油田公司勘探开发研究院,敦煌,736202 3. 中国地质科学院地质力学研究所,北京,100081 |
| 基金项目： | 国家自然科学基金项目（面上项目，重点项目，重大项目） |
| 摘 要： | 阿尔金造山带是青藏高原北缘一条受到走滑断裂强烈改造的碰撞造山带,构成了现今青藏高原北部的构造边界。阿尔金造山带的隆升是青藏高原隆起过程的重要组成部分。本文对柴达木盆地西北部干柴沟剖面的下干柴沟组(E31)和下油砂山组下段(N12)砂岩的碎屑锆石进行了LA-ICP-MSU-Pb年代学分析,并对这些样品进行了碎屑重矿物分析。本文分析的第三系砂岩样品的碎屑锆石U-Pb年龄谱中均包括显著的印支期和加里东期的年龄峰期,下干柴沟组和下油砂山组的年龄谱存在明显的差别:下干柴沟组样品的年龄谱中印支期峰值相对显著,而下油砂山组样品的年龄谱中加里东期峰值逐渐变得显著。重矿物组合的稳定系数也从下干柴沟组到下油砂山组迅速降低,说明碎屑由高成熟度转变为低成熟度,物源由远变近。由此证实渐新世早期和上新世早期阿尔金经历了强烈的隆升。尽管阿尔金造山带经历的碰撞造山过程早在早古生代就已结束,但是现今出露的阿尔金山系主要是在新生代经受构造运动而隆起形成的。此工作也证实碎屑锆石年龄谱结合重矿物组合分析是研究地层物源和盆山耦合的一种有效的方法。 |
| 关 键 词： | 柴达木 阿尔金 碎屑锆石 LA-ICP-MS |
| 收稿时间： | 2010/7/29 0:00:00 |
| 修稿时间： | 2010/11/30 0:00:00 |
Detrital Zircon LA-ICP-MS ages of Tertiary sandstones from western Qaidam basin- constraints on the uplift of Altun mountains |
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| Zhou Hai,Chen Liang.Detrital Zircon LA-ICP-MS ages of Tertiary sandstones from western Qaidam basin- constraints on the uplift of Altun mountains[J].Acta Geologica Sinica,2012,86(6):906-922. | |
| Authors: | Zhou Hai Chen Liang |
| Institution: | Department of Geology, Northwest University,Dept.of Geology, Northwest University |
| Abstract: | The Altun mountains along the Northern margin of the Qaidam basin is a collisional orogenic belt strongly modified by strike-slip-faults, constituing the current nothern tectonic boundary of Qinghai-Tibet Plateau. Its uplift is remarkable part of the cenozoic uplift of Qinghai-Tibet Plateau. In this contribution, we present LA-ICPMS U-Pb dating results of detrital zircons, together with heavy mineral assemblages from sandstones of the Xiaganchaigou formation (E31) and lower segment of the Xiayoushashan formation (N21) from northwest Qaidam Basin. Our results show that there are significant Indosinian and Caledonian age populations in all samples. However, significant differences in age spectrums exist between the samples from Xiaganchaigou formation ages and those from Xiayoushashan formation. Indosinian peaks in the ages spectrums of Xiaganchaigou samples are stronger than those of Xiaganchaigou, whereas the of Caledonian peak gradually become stronger in Xiayoushashan samples. The stability of Heavy mineral assemblages decrease severely from the Xiaganchaigou formation to the Xiayoushashan formation , indicating that their debris changed from a high maturity into a low maturity level, reflecting that provenance area for the Xiaganchaigou formation is much farther than the Xiayoushashan formation. All these results imply that Altun experienced a significant uplift in the the early Oligocene and early Pliocene. Although the subduction-collision orogeneiss of Altun belt orogenic belt was completed in the early Paleozoic., the currently exposed Altun mountains was primarily formed by much later tectonic movement, i.e. uplifting asociated with strike-slip faulting in Cenozoic. This work also confirmed the U-Pb age spectrum of detrital zircon, associated with heavy mineral assemblage analysis is an effective tool in research of strat provenance and basin-mountain coupling. |
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