| 龙门山构造带晚新生代剥蚀作用与均衡隆升的地表过程研究 |
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| 引用本文：闫亮,李勇,邓涛,颜照坤,云锟,邵崇建,董顺利.2019.龙门山构造带晚新生代剥蚀作用与均衡隆升的地表过程研究[J].地球学报,40(1):76-92. |
| DOI：10.3975/cagsb.2018.111301 |
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| 基金项目:国家自然科学基金项目(编号: 41402159; 41741003; 40841010; 40972083; 41172162; 41372114; 41340005; 41502116);国家重点研发计划项目(编号: 2017YFC1501000);中国地质调查局地质调查工作项目(编号: 121201010000150004-08; 12120115004501-01);油气藏地质及开发工程国家重点实验室(成都理工大学)自主研究课题(编号: SK-0801) |
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| 中文摘要:基于SRTM DEM数据, 以青藏高原东缘龙门山地区为研究区域, 本文通过条带状剖面分析、古地形面(残余面)恢复以及弹性挠曲模拟等研究手段, 计算了青藏高原东缘龙门山地区晚新生代地壳均衡隆升与地表剥蚀之间的定量关系, 探讨了龙门山地区表面剥蚀作用与均衡隆升作用之间的地表响应过程, 从而为研究青藏高原东缘龙门山地区晚新生代以来的剥蚀—成山作用的隆升机制提供定量依据。研究表明: (1)晚新生代以来龙门山的地表剥蚀量为(0.74~1.14)×105 km3; (2)大量的地表剥蚀作用驱动了青藏高原东缘龙门山的地壳均衡反弹, 使龙门山隆升了近2 km; (3)龙门山地区地表剥蚀量和均衡隆升量具有空间匹配性, 岷山断块及龙门山中、南段的均衡隆升量高于青藏高原东缘其它区域, 反映了晚新生代以来龙门山地区在不同分段内差异化的构造地貌形态及与剥蚀—隆升相关的地表过程。(4)龙门山的隆升是多期、多种隆升机制叠加的产物, 其隆升过程具有历史性和复合性。均衡隆升和剥蚀作用在相似的时间尺度上和空间尺度上控制着龙门山地貌的形成, 约束了青藏高原东缘龙门山的隆升机制。 |
| 中文关键词:古地形面(残余面)恢复 弹性挠曲模型 地表剥蚀 均衡隆升 龙门山 青藏高原东缘 |
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| Late Cenozoic Surface Process Caused by Denudation and Isostatic Rebound of the Longmen Shan Tectonic Belt on the Eastern Margin of the Tibetan Plateau |
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| Abstract:On the basis of the SRTM DEM data, with the Longmen Shan on the eastern margin of the Tibetan Plateau as the research area and in combination with the analyzing swath profiles, rebuilding paleo-residual surfaces and simulating elastic deflection model, the authors calculated the quantitative relationship between isostatic rebound and surface erosion of the Longmen Shan area in Late Cenozoic, and discussed the surface response process of the Longmen Shan caused by the effect of denudation and isostatic uplift. The results provide a basis for quantitative study of the uplift mechanism of the Longmen Shan on the eastern margin of the Tibetan Plateau since Late Cenozoic. Firstly, the value of the surface denudation volume in the Longmen Shan is (0.74~1.14)×105 km3 , There is a high value of the erosion amount in Minshan block, the middle and lower reaches of Fujiang River, Minjiang River, Qingyi River and three main faults of the Longmen Shan. Among them, the value of the denudation volume in Minshan block area is about 17%~21% of the total denudation volume, the denudation amount in the northern segment of Longmen Shan is approximately 20%~23%, the denudation amount is about 28%~34% in the middle segment, and the denudation amount is about 24%~29% in the southern segment. Secondly, a large amount of surface denudation drived isostatic rebound of the Longmen Shan on the eastern margin of the Tibetan Plateau, of which the value was nearly 2 km. Thirdly, there has been a spatial matching feature between the amount of surface denudation and isostatic uplift in the Longmen Shan since Late Cenozoic. The value of isostatic uplift in Minshan block, the middle and southern segment of the Longmen Shan was bigger than the other areas of the Tibetan Plateau. It is thus shown that there have been different features of structure morphology and surface processes associated with denudation-uplift in different segments of Longmen Shan area since Late Cenozoic. The history of Longmen Shan’s uplift is a production of multiphase and superposition of multiple uplifting mechanism, which has been a historical and compound uplift process. It is held that the isostatic uplift and surface denudation control the relief of the Longmen Shan in the same time scale and space scale, and constrain the uplifting mechanism of the Longmen Shan on the eastern margin of the Tibetan Plateau. |
| keywords:paleo-residual surface reconstruction flexural deflection model surface denudation isostatic uplift Longmen Shan eastern margin of the Tibetan Plateau |
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