| 根据碎屑白云母40Ar/39Ar年龄追索喜马拉雅造山带的剥落历史——对青藏高原隆升过程的启示 |
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| 引用本文： | 段,亮.根据碎屑白云母40Ar/39Ar年龄追索喜马拉雅造山带的剥落历史——对青藏高原隆升过程的启示[J].地质通报,2010,29(1):70-78. |
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| 作者姓名： | 段 亮 |
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| 作者单位： | 西北大学大陆动力学国家重点实验室/西北大学地质学系,陕西,西安,710069 |
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| 基金项目： | 西北大学研究生自主创新基金项目 |
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| 摘 要： | 对喜马拉雅前陆盆地和孟加拉海扇中各地层的碎屑白云母40Ar/39Ar资料的系统分析揭示了喜马拉雅造山带自印度-欧亚板块碰撞开始造山以来的整个剥落历史: 剥落速率开始较为稳定，然后开始上升，在22Ma左右达到峰值，为4~5mm/a，随后急剧下降，最终以2mm/a的速率保持平稳。喜马拉雅造山带与青藏高原周缘剥落历史的对比约束了印度-欧亚板块碰撞造成青藏高原东缘和北缘的不同反应方式。即开始时的挤压主要被青藏高原北缘的大规模左旋走滑吸收, 到30Ma左右，喜马拉雅造山带冷却、剥落速率显著增强，北缘左旋走滑造成的柴达木地块的向东运动被华北板块阻挡而停滞，因此在北缘发生了一些重要的冷却和抬升剥落事件。至18Ma左右，喜马拉雅造山带的冷却、剥落速率继续增高并维持在较高水平，而该时间段内无论是北缘还是东缘，均未发生显著的抬升剥落事件，因此青藏高原的整体隆升和地壳增厚可能发生在此期间。中新世末—上新世初开始至今，青藏高原东缘龙门山地区发生了一些显著的抬升剥落事件，导致了大量的山崩和河流侵蚀，即此时来自喜马拉雅的挤压主要被青藏高原向东方向的地壳逃逸所吸收。
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| 关 键 词： | 40Ar/39Ar年龄 白云母 剥落历史 喜马拉雅造山带 隆升过程 青藏高原 |
Tracing the exhumation history of the Himalaya orogenic zone by detrital muscovite 40Ar/39Ar dating: implications for uplifting process of the Qinghai-Tibet Plateau, China |
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| DUAN Liang.Tracing the exhumation history of the Himalaya orogenic zone by detrital muscovite 40Ar/39Ar dating: implications for uplifting process of the Qinghai-Tibet Plateau, China[J].Geologcal Bulletin OF China,2010,29(1):70-78. |
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| Authors: | DUAN Liang |
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| Institution: | DUAN Liang State Key Laboratory of Continental Dynamics/Department of Geology,Northwest University,Xi\'an 710069,Shaanxi,China |
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| Abstract: | Systematic analysis of detrital muscovite 40Ar/39Ar data from the Himalayan foreland basin and Bengal fan stratigraphic units reveals the entire exhumation history of the Himalaya orogen since India-Asia plate collision event. The exhumation process was steady at the beginning, then increased up to the peak in around 22Ma with a rate of 4~5mm/a, subsequently, dropped dramatically and kept even ultimately with the rate of 2mm/a. The comparison of the exhumation histories between the edge of Tibetan Plateau and the Himalaya orogen could restrict the different reacting ways of the east and north boundaries of the Tibetan Plateau induced by India-Asia collision. The compression force was mainly absorbed in the first instance by large scale left-lateral strike-slip in the north edge of Tibetan Plateau till 30 Ma, which was followed by an important cooling and exhumation event triggered by the stagnancy of eastward movement of the Qaidam Block due to the countercheck of the North China Craton. Subsequently, with the continuous increasing of the cooling-exhumation rate in Himalaya and sustaining at a high level until 18 Ma and no marked exhumation event occurred either in north edge or east boundary, entire uplift and crust thickening of the Tibetan Plateau may occurred in this period. From late Miocene - early Pliocene to now, a series of pronounced uplift and exhumation events happened in the east edge resulted in large amounts landslides in conjunction with coeval river erosion, that means the compression force from the Himalaya was mainly absorbed by lateral growth and crust escaping of the Tibetan Plateau in the direction of east. |
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| Keywords: | 40Ar/39Ar age muscovite exhumation history Himalaya orogenic zone uplift process Tibetan Plateau |
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