Monsoon and earthquake controls on sediment flux in an arid bedrock landscape, Zanskar, India

量化侵蚀速率和泥沙通量在喜马拉雅等构造活跃的山区有着悠久的传统。相比之下，人们对间歇性泥沙储存的作用及其对景观演变的影响知之甚少。拟议的项目解决了这一缺点，旨在研究印度赞斯卡尔地区西北喜马拉雅潮湿-干旱过渡的第四纪晚期山内沉积记录。具体地说，我打算解决导致在原本被陡峭的基岩河流切割的集水区形成和切割大型山谷填充物的原因。全新世早期季风环流增强和史前大地震可能是造成河谷底部快速堆积的可能机制之一，这种快速堆积显著延迟了河流基岩切割，减少了局部山谷起伏，缓冲了山坡泥沙向河道的输送，总体上有助于减缓地形对构造抬升的响应。研究方法将结合地理信息系统和遥感分析、放射性年龄测定、沉积学和地貌学现场技术以及数值过程模拟，以便一级量化大山谷填充对喜马拉雅西北部晚第四纪景观动态的影响。

Quantifying rates of erosion and sediment flux has a long tradition in tectonically active mountain belts such as the Himalaya. Comparably little is known about the role of intermittent sediment storage and its implications for landscape evolution. The proposed project addresses this shortcoming, and aims to investigate the late Quaternary intramontane sedimentary record of the NW Himalayan humid-arid transition in the Zanskar region, India. Specifically, I intend to resolve the causes that led to the formation and incision of large valley fills in catchments otherwise dissected by steep bedrock rivers. A strengthened early Holocene monsoon circulation and large prehistoric earthquakes are among the likely mechanisms to explain the rapid aggradation of valley floors that significantly delay fluvial bedrock incision, reduce local valley relief, buffer hillslope sediment delivery to river channels, and generally contribute to slowing down landscape response to tectonic uplift. Study methods will combine GIS and remote sensing analyses, radiometric age dating, sedimentological and morphometric field techniques, and numerical process modelling in order to quantify to first order the effects of large valley fills on late Quaternary landscape dynamics in the NW Himalaya.