Paleotopographic controls on loess deposition in the Loess Plateau of China
Paleotopographic controls on loess deposition in the Loess Plateau of China
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DOI：
10.1002/esp.3883
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发表时间：
2016-07
影响因子：
3.3
通讯作者：
Li-yang Xiong;G. Tang;J. Strobl;A. Zhu
中科院分区：
文献类型：
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作者：
Li-yang Xiong;G. Tang;J. Strobl;A. Zhu
下伏古地形直接影响黄土的沉积过程，并塑造了现今黄土地貌的形态。了解下伏古地形对黄土沉积的控制作用是揭示黄土地貌形成机制的关键。然而，这些控制效应表现出空间变化以及不确定性，这取决于研究的数据来源，方法和特定的研究范围。本文利用详细的地质资料和数字高程模型（DEM）对黄土高原一个水土流失严重的研究区的地质历史进行了研究，并建立了该地区的古地形模型。基于现代地形和古地形模型，引入流域层次分析方法，研究黄土-地貌继承关系的空间变化，揭示黄土在不同流域尺度上的沉积过程。地貌继承关系的特点是使用地形起伏变化指数（TRCI）和基岩地形可控性指数（BTCI）。结果表明，TRCI似乎有一个反向关系，增加研究范围，表明，与该地区的古地形相比，现代地形具有较低的地形起伏在整个地区，而它具有较高的地形起伏在较小的，局部地区。随着流域面积的增加，BTCI增强，这表明了对整个研究区域的强烈控制作用，但由于古地形对现代地形的影响，在较小的局部区域的影响较弱。研究结果有助于理解黄土沉积与古地形的空间变化关系，并有助于建立基于过程的黄土地貌演化模型。版权所有© 2015约翰威利父子有限公司.
The underlying pre‐existing paleotopography directly influences the loess deposition process and shapes the morphology of current loess landforms. An understanding of the controlling effects of the underlying paleotopography on loess deposition is critical to revealing the mechanism of loess‐landform formation. However, these controlling effects exhibit spatial variation as well as uncertainty, depending on a study's data sources, methodologies and particular research scope. In this study, the geological history of a study area in the Loess Plateau of China that is subject to severe soil erosion is investigated using detailed geological information and digital elevation models (DEMs), and an underlying paleotopographic model of the area is constructed. Based on the models of modern terrain and paleotopography, we introduce a watershed hierarchy method to investigate the spatial variation of the loess‐landform inheritance relationship and reveal the loess deposition process over different scales of drainage. The landform inheritance relationships were characterized using a terrain‐relief change index (TRCI) and a bedrock terrain controllability index (BTCI). The results show that the TRCI appears to have an inverse relationship with increasing research scope, indicating that, compared with the paleotopography of the region, modern terrain has lower topographic relief over the entire area, while it has higher topographic relief in the smaller, local areas. The BTCI strengthens with increasing drainage area, which demonstrates a strong controlling effect over the entire study area, but a weak effect in the smaller, local areas because of the effect of paleotopography on modern terrain. The results provide for an understanding of the spatial variation of loess deposition in relation to paleotopography and contribute to the development of a process‐based loess‐landform evolution model. Copyright © 2015 John Wiley & Sons, Ltd.