Squeezing river catchments through tectonics: Shortening and erosion across the Indus Valley, NW Himalaya
Squeezing river catchments through tectonics: Shortening and erosion across the Indus Valley, NW Himalaya
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构造挤压河流集水区：喜马拉雅西北部印度河流域的缩短和侵蚀
DOI：
10.1130/b31435.1
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发表时间：
2017
影响因子：
4.9
通讯作者：
Sinclair H
中科院分区：
文献类型：
--
作者：
Sinclair H
在地壳缩短过程中，一些山脉的排水分水岭发生了构造位移，河流网络随之发生了变形，但从未得到验证。为了保持地表地形中的地壳应变，必须保留逆冲断层上的地表位移，而不会因随之而来的侵蚀而恢复。这些竞争过程的量化和流域地形的影响以前没有得到证明。在这里，我们使用结构映射结合阶地沉积物的测年来测量第四纪缩短横跨印度河流域拉达克，西北喜马拉雅。计算结果表明，自1980年以来，水平位移为1.021 m k.y.-1。45 ka的Stok逆冲断层，它定义了印度河流域的西南边缘，是该地区特提斯喜马拉雅山的主要逆冲断层。我们使用归一化的河道梯度的支流，流入印度河表明，斯托克逆冲断层的横向延续是活跃的至少70公里沿着走向。缩短率与故障的几何形状相结合，产生的垂直位移率相比，时间等效的侵蚀率在上盘来自已发表的碎屑10 Be分析。结果表明，垂直位移率横跨斯托克逆冲断层约两倍的时间等效侵蚀率，这意味着净水平位移的表面地形，因此缩小的印度河流域在100.1米公里-1。一个填充阶地记录了与逆冲活动有关的碎屑流就位，导致了山谷的筑坝和广泛的湖泊发展。一些现代冲积扇下的砾岩表明，印度河河道自公元前向东北移动。45 ka时，其目前的路线与Stok逆冲断层山谷的另一侧相反。结构，地形，侵蚀和沉积学数据的整合提供了第一次演示的构造收敛的排水划分在山脉，并产生一个模型的表面过程。
Tectonic displacement of drainage divides and the consequent deformation of river networks during crustal shortening have been proposed for a number of mountain ranges, but never tested. In order to preserve crustal strain in surface topography, surface displacements across thrust faults must be retained without being recovered by consequent erosion. Quantification of these competing processes and the implications for catchment topography have not previously been demonstrated. Here, we use structural mapping combined with dating of terrace sediments to measure Quaternary shortening across the Indus River valley in Ladakh, NW Himalaya. We demonstrate ∼0.21 m k.y.–1of horizontal displacement since ca. 45 ka on the Stok thrust in Ladakh, which defines the southwestern margin of the Indus Valley catchment and is the major back thrust to the Tethyan Himalaya in this region. We use normalized river channel gradients of the tributaries that drain into the Indus River to show that the lateral continuation of the Stok thrust was active for at least 70 km along strike. Shortening rates combined with fault geometries yield vertical displacement rates that are compared to time-equivalent erosion rates in the hanging wall derived from published detrital10Be analyses. The results demonstrate that vertical displacement rates across the Stok thrust were approximately twice that of the time-equivalent erosion rates, implying a net horizontal displacement of the surface topography, and hence narrowing of the Indus Valley at ∼0.1 m k.y.–1. A fill terrace records debris-flow emplacement linked to thrust activity, resulting in damming of the valley and extensive lake development. Conglomerates beneath some of the modern alluvial fans indicate a northeastward shift of the Indus River channel since ca. 45 ka to its present course against the opposite side of the valley from the Stok thrust. The integration of structural, topographic, erosional, and sedimentological data provides the first demonstration of the tectonic convergence of drainage divides in a mountain range and yields a model of the surface processes involved.
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DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
B. Phartiyal;Anupam Sharma;R. Upadhyay;Ram‐Awatar;A. K. Sinha
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影响因子：
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L. Kirstein;J. Foeken;P. A. van der Beek;F. Stuart;R. Phillips
影响因子：
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R. Devrani;Vimal Singh;S. Mudd;Hugh D. Sinclair
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R. Devrani;Vimal Singh;S. Mudd;Hugh D. Sinclair
断层弯曲褶皱上的地形平流：山谷位置的继承和风隙的形成
DOI：
--
发表时间：
2006
期刊：
影响因子：
--
作者：
Scott R. Miller;Rudy Slingerland
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DOI：
10.1144/gsl.sp.2000.170.01.14
发表时间：
2000
期刊：
Geological Society, London, Special Publications
影响因子：
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作者：
Roberto F. Weinberg;W. Dunlap;M. Whitehouse
通讯作者：
M. Whitehouse