Numerical modeling of mountain building: Interplay between erosion law and crustal rheology
Numerical modeling of mountain building: Interplay between erosion law and crustal rheology
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造山的数值模拟：侵蚀规律与地壳流变学之间的相互作用
DOI：
10.1029/2004gl021006
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发表时间：
2004
影响因子：
5.2
通讯作者：
J. Lavé
中科院分区：
文献类型：
--
作者：
Vincent Godard;R. Cattin;J. Lavé
侵蚀和构造之间的耦合被认为在造山演化中起着决定性作用。在这里，我们研究假设的侵蚀规律和碰撞高原边缘的地壳流变学之间的相互作用，比如尼泊尔中部的喜马拉雅山脉。在100KYR的时间尺度上，通过结合地壳的流变分层和跨范围收敛的主要特征的2D有限元模型计算了岩石圈的变形。在上边界条件下，试验了两种地表过程：线性扩散模式和包含沿河网的河流切割和滑坡侵蚀的1D_1/2一体化模式。根据约束性地质和地貌观测，讨论了模型结果及其对选定的侵蚀规律和地壳性质组合的敏感性。与Cattin和Avouac[2000]的结论不同，我们将地壳的石英-辉绿岩复合流变学与河流切割侵蚀规律结合起来，以解释尼泊尔中部喜马拉雅地区的侵蚀和高程剖面。更广泛地说，由于主要的剥蚀条件和地壳流变学之间的相互作用，有充分证据的侵蚀速率和过程都可以对活动造山带内的地壳性质提供显著的限制。
Coupling between erosion and tectonics is thought to play a determinant role in orogenic evolution. Here, we investigate the interplay in this coupling between the assumed erosion law and the crustal rheology at the margin of a collisional plateau, like the Himalaya of Central Nepal. Lithospheric deformation is calculated over a time scale of 100 kyr by a 2D finite element model that incorporates the rheological layering of the crust and the main features of the convergence across the range. For the upper boundary condition, two surface processes were tested: a linear diffusion model and a 1D1/2 integrative model including fluvial incision along the fluvial network and hillslope erosion by landsliding. Model results and their sensitivity to the chosen combinations of erosion law and crustal properties are discussed in light of the constraining geologic and geomorphologic observations. In contrast with the conclusions of Cattin and Avouac [2000] , where a compliant quartz‐rich crustal rheology and diffusion law were required, we combine a composite quartz‐diabase rheology for the crust with fluvial incision erosion law to account for erosion and elevation profiles across the Himalaya of Central Nepal. More generally, it is proposed that, because of the interplay between the dominant denudation conditions and the rheology of the crust, both well documented erosion rates and processes can provide significant constraints on crustal properties within an active orogen.