Collaborative Research: Geomorphic legacy of megaflood deposits on river processes and form, Eastern Himalaya

合作研究：喜马拉雅东部大洪水沉积物对河流过程和形态的地貌遗产

• 批准号: 2220336
• 负责人: Katharine Huntington
• 金额: $ 23.41万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2220336&HistoricalAwards=false
• 关键词: Collaborative; Research; Geomorphic; legacy; megaflood

Earth and other planetary landscapes contain a record of both past and present surface processes. During colder climate periods thousands of years ago, glacial ice and debris episodically dammed rivers, leading to catastrophic floods of a magnitude not seen on Earth today. Such “megafloods” left an indelible signature on landscapes across nearly every continent, and geologists rely on rare flood deposits to reconstruct how megafloods have shaped the landscapes we see today. This project focuses on unique flood deposits from the eastern Himalayan mountains, using new observations, measurements, and computer modeling to study how catastrophic flood events contribute to the evolution of a steep, high-relief mountain landscape. This project also uses the fascinating story of megafloods to develop publicly accessible K-12 educational materials that integrate scientific discovery with Indigenous Knowledge and will support training of multiple graduate and undergraduate students. The results of this work will help to more accurately interpret the origin of the landscapes seen on both Earth and Mars today – as well as to better predict hazards from similarly catastrophic anthropogenic analogues, such as flooding after the failure of a dam. Prior megaflood research has focused on the impact of dam-burst megaflood discharges (10^6 m3/s) on bedrock channel erosion. This project will further explore the role of megaflood deposition on the long-term (10^3 yr) evolution of bedrock rivers. The project team will focus on a well-documented example of megaflood deposition along the Yarlung-Siang-Brahmaputra river system in the eastern Himalaya to: 1. determine the source, depositional age and grain size distribution of flood deposits using cutting-edge analytical tools, 2. develop a process-based numerical model to predict first-order changes to a bedrock river channel following abrupt flood aggradation, and 3. search for a unique topographic signature of megaflood processes by comparing the morphology of eastern Himalayan river channels with and without a history of megaflooding. These findings will illuminate how intermontane sediment deposition by megafloods governs river valley evolution. Ultimately, the results have the potential to change the way sediment deposition is considered in numerical models of eroding mountainous landscapes and will provide new insight into the role of infrequent, high-magnitude flood events in shaping landscapes on both Earth and Mars.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

地球和其他行星景观包含过去和现在的表面过程的记录。在数千年前的附带期间，冰川冰和碎屑会发出污染的河流，导致今天地球上没有看到的灾难性浮标。这种“大型富裕”几乎在几乎每个大陆的景观上都留下了难以置信的签名，地质学家依靠稀有的洪水沉积物来重建大型富裕人如何塑造我们今天看到的景观。该项目使用新的观察，测量和计算机建模来研究来自喜马拉雅东部东部的独特洪水沉积物，以研究灾难性洪水事件如何促进钢制高浮雕山景的演变。该项目还使用令人着迷的大型氟中心的故事来开发可公开访问的K-12教育材料，这些材料将科学发现与土著知识相结合，并将支持对多个研究生和本科生的培训。这项工作的结果将有助于更准确地解释当今地球和火星上景观的起源 - 以及更好地预测类似灾难性的人为类似物的危害，例如大坝失败后的洪水。先前的Megaflood Research集中于大坝爆发巨型排放（10^6 m3/s）对基岩通道侵蚀的影响。该项目将进一步探讨大型沉积物对基岩河流的长期演变（10^3年）的作用。项目团队将重点介绍一个有据可查的巨型散发沉积范围的例子大型过程通过比较东部喜马拉雅河河道的形态与有和没有大型富裕历史的形态。这些发现将阐明跨蒙托坦沉积物的沉积如何控制河谷的进化。 Ultimately, the results have the potential to change the way sediment deposition is considered in numerical models of eroding mountainous landscapes and will provide new insight into the role of infrequent, high-magnitude Flood events in shaping landscapes on both Earth and Mars.This award reflects NSF's statutory mission and has been deemed precious of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

项目成果

The Erosional and Depositional Potential of Holocene Tibetan Megafloods Through the Yarlung Tsangpo Gorge, Eastern Himalaya: Insights From 2D Hydraulic Simulations

• DOI: 10.1029/2021jf006498
• 发表时间: 2022-04
• 期刊: Journal of Geophysical Research: Earth Surface
• 作者: Susannah M. Morey;K. Huntington;Michael D. Turzewski;Mahathi Mangipudi;David R. Montgomery