Whipp D M, Ehlers T A
Institute of Seismology, Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.
Department of Geosciences, University of Tübingen, Tübingen, Germany.
Sci Adv. 2019 Apr 24;5(4):eaav3482. doi: 10.1126/sciadv.aav3482. eCollection 2019 Apr.
Quantifying how Earth surface processes interact with climate, tectonics, and biota has proven challenging, in part due to the stochastic nature of erosion and sedimentation. Landsliding is a common stochastic erosional process that may account for >50% of the sediment produced in steep mountainous landscapes. Here, we calculate the effects of landsliding and the residence time of sediment in a steep drainage basin in the Nepal Himalaya using a numerical model of landslide erosion combined with published cooling age distributions from two river sediment samples collected several years apart. We find that the difference in the two samples can be explained by landsliding and that the age distributions suggest that the residence time of sediment in the catchment is no greater than 50 years. This sensitivity to landsliding thus offers potential to improve our understanding of stochastic erosional processes, and further suggests that sediment is rapidly evacuated from steep mountainous drainage basins.
事实证明，量化地球表面过程如何与气候、构造和生物群相互作用具有挑战性，部分原因是侵蚀和沉积具有随机性。山体滑坡是一种常见的随机侵蚀过程，在陡峭的山区景观中，它产生的沉积物可能占沉积物总量的50%以上。在这里，我们使用滑坡侵蚀数值模型，并结合几年间采集的两个河流沉积物样本的已发表冷却年龄分布，来计算尼泊尔喜马拉雅山一个陡峭流域内山体滑坡的影响以及沉积物的停留时间。我们发现，两个样本的差异可以用山体滑坡来解释，年龄分布表明沉积物在集水区的停留时间不超过50年。因此，这种对山体滑坡的敏感性为增进我们对随机侵蚀过程的理解提供了可能，并且进一步表明沉积物会迅速从陡峭的山区流域中排出。
