Simulating tectonically controlled fractal landscape evolution in the Three Rivers Region (SE Tibetan Plateau margin)
Simulating tectonically controlled fractal landscape evolution in the Three Rivers Region (SE Tibetan Plateau margin)
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DOI：
10.1016/j.geomorph.2023.108957
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发表时间：
2023-11
期刊：
影响因子：
3.9
通讯作者：
Zhenzhen Yan;Yaolin Shi;Lili Kang;Xiangtao Fan
中科院分区：
文献类型：
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作者：
Zhenzhen Yan;Yaolin Shi;Lili Kang;Xiangtao Fan
河流景观的长期发展对构造运动十分敏感。位于青藏高原东南缘的三江地区就是这种情况，在那里，它对于理解印度和欧亚板块之间的持续碰撞和挤压至关重要。然而，这种景观演变的定量观点是缺乏的。基于现有的全球定位系统（GPS）数据，提出了区域变形的两个阶段（北东-西南向缩短和右旋剪切变形）的定量表达，以表征印度-欧亚大陆的持续碰撞。通过将这种构造格局纳入景观演化模型，并结合区域差异隆升，数值模拟结果定量地呈现了青藏高原东南缘怒江、澜沧江和金沙江的动态塑造。对这些水系的分维分析表明，两个构造变形阶段显著地控制了区域景观的发展及其独特的水系特征。数值模拟描绘了河流网络，包括非常长和相对直的树干，和相对小和短的支流。构造缩短及其伴随的快速抬升阻止了支流的发展和延长，这可能促进了低起伏表面的形成。与数字高程模型（DEM）相比，尽管数值模型较为简单，但从数值结果中提取的河网分形特征与从天然河网中提取的特征一致。更广泛地说，基于更现实的运动学场景和合理的约束，这项研究有助于开发一个有效的和适用的模型，可以揭示该地区的景观演变的重要影响。
The long-term development of fluvial landscapes is sensitive to tectonic movement. This is the case for the Three Rivers Region, located on the southeastern margin of the Tibetan Plateau, where it is critical for understanding the continuous collision and compression between the Indian and Eurasian plates. However, quantitative perspectives on this landscape evolution are lacking. Based on present global positioning system (GPS) data, a quantitative expression of two phases of regional deformation, a northeast-southwest shortening and dextral shear deformation, was proposed to represent the continuous Indian-Eurasian collision. By incorporating this tectonic pattern into a landscape evolution model and integrating the regional differential uplift, the numerical results quantitatively present a dynamic shaping of the Nu, Lancang, and Jinsha rivers in the SE Tibetan plateau margin. Analyses of the fractal dimensions of these river networks indicate that two tectonic deformation phases significantly controlled regional landscape development and its unique drainage features. The numerical simulations depict the river networks to comprise very long and relatively straight stream trunks, and relatively small and short tributaries. The tectonic shortening and its accompanying rapid uplift prevented the development and lengthening of the tributaries, which might have promoted the formation of low-relief surfaces. With comparison to the digital elevation model (DEM), the fractal features of the river networks extracted from the numerical results are consistent with those extracted from the natural river networks, despite the simplicity of the numerical model. More broadly, based on the more realistic kinematic scenarios and reasonable constraints, this study contributes to the development of an effective and applicable model that can reveal important implications for the landscape evolution of the region.