Glacial and fluvial erosion in the Dolpo Basin, Western Nepal
Glacial and fluvial erosion in the Dolpo Basin, Western Nepal
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DOI：
10.1016/j.geomorph.2020.107033
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发表时间：
2020-04
期刊：
影响因子：
3.9
通讯作者：
Rhys E. Buceta;L. Schoenbohm;P. DeCelles
中科院分区：
文献类型：
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作者：
Rhys E. Buceta;L. Schoenbohm;P. DeCelles
尼泊尔西部的地貌受到地质构造以及冰川和河流侵蚀的巨大影响。在这里，我们调查的现代地貌和冰川特征的多尔波盆地在尼泊尔北方中西部。我们分析属性，如冰川的大小，坡度，方面和脚趾，头部和峰值海拔为446冰川内和周围的盆地，确定其与盆地特征，如岩性，坡度和降水的关系。冰川反映岩性和降水，但冰川的大小与基准面和坡度密切相关。我们的数据表明，具有高基准面的低坡度冰川，即，那些流到青藏高原的，因为它们处于或高于平衡线的高度，所以被迫变大。盆地内的冰川，特别是西部的冰川，可能在陡坡上被肢解，降水只能部分抵消这种影响。区域坡度的空间变异性以及北方盆地边界沿着风隙的存在表明多尔波盆地最近被占领。因此，高原状地貌曾经向南延伸至少45公里。盆地向南的开口使降水进入，形成了沿着盆地北方边界西端的冰川。随着时间的推移，较大的冰川（由于高基准面）通过溯源侵蚀将海脊推向南方。我们的研究表明，尼泊尔西部的景观发生了戏剧性的重组，这与其他最近的研究一致，表明了一个更广泛的原始西藏。
The landscape of Western Nepal has been dramatically shaped by tectonics and by both glacial and fluvial erosion. Here we investigate the modern geomorphic and glacial features of the Dolpo basin in northern mid-western Nepal. We analyze attributes such as glacier size, slope, aspect and toe, head and peak elevation for 446 glaciers within and around the basin, determining their relationship with basin features such as lithology, slope and precipitation. Glaciers reflect lithology and precipitation, but glacier size is strongly correlated with base-level and slope. Our data suggest that low-slope glaciers with high base-level, i.e., those that flow onto the Tibetan plateau, are forced to grow large because they exist at or above the equilibrium-line altitude. Glaciers within the basin, particularly in the western part, can become dismembered on steep slopes, an effect only partly offset by precipitation. The spatial variability in regional slope and presence of a wind gap along the northern basin border suggest recent capture of the Dolpo basin. A plateau-like morphology would have thus once extended at least 45 km southward. The southward opening of the basin allowed precipitation to enter, forming glaciers along the western end of the northern basin border. Larger glaciers (resulting from high base-level) pushed the ridge southward over time through headward erosion. Our study suggests dramatic landscape reorganization in western Nepal, consistent with other recent studies suggesting a more extensive proto-Tibet.