NSFGEO-NERC Collaborative Research: Coupling Erosion, Weathering, and Hydrologic Function in an Active Orogenic System

NSFGEO-NERC 合作研究：活跃造山系统中侵蚀、风化和水文功能的耦合

• 批准号: 2021619
• 负责人: A Joshua West
• 金额: $ 160.54万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2021619&HistoricalAwards=false
• 关键词: NSFGEO; NERC; Collaborative; Research; Coupling

Mountain ranges are some of the most spectacular features of the Earth’s surface, but their importance extends far beyond their photogenic nature. Mountains play critical roles in sustaining key natural resources, such as supplying fresh water to large human populations. Mountainous regions are the site of many destructive natural hazards, such as landslides and floods. In addition, mountains are where fresh rocks are exposed to water and the atmosphere, resulting in chemical reactions that can modify carbon dioxide and climate over geologic time. These processes are all closely interconnected, yet they have been largely studied in isolation. This project will examine the physical and chemical transformation of rock together with the flow of water and Earth materials within the scope of one integrated research endeavor. The project will examine these processes in a valley in the Himalaya Mountains of Nepal where topography changes from more subdued in the south to high mountains in the north. Cutting-edge techniques for documenting the nature and rate of landscape change will be applied to determine the role of mountains in the Earth system. Models that illustrate how all these processes interact and the effects they produce will be developed to forecast future changes and apply the results to other regions. The research will involve training of multiple graduate and undergraduate researchers and will involve collaboration among researchers from four countries. The collisional boundaries between Earth’s tectonic plates produce dramatic mountain ranges that generate destructive natural hazards as well as chemical and physical exchanges that control the surface environment. This project will comprise a multi-disciplinary investigation of four interrelated problems: (1) how rock is transformed physically and chemically during exhumation in tectonically-active mountains; (2) how the steep mountainous topography of active orogens develops, and particularly what the role is for landslides; (3) how water makes its way from precipitation, through the subsurface, and into streams and rivers draining active orogens; and (4) how chemical weathering depends on tectonic and climatic conditions in these settings. The project will investigate the Melamchi Khola valley in central Nepal, where a pronounced south-to-north gradient in exhumation rate offers an ideal opportunity to document system-level relationships among tectonics, topographic evolution, erosion, hydrology, and chemical weathering in an archetypal setting of collisional tectonics. The research will (1) characterize rock mass across scales from the micron to kilometer, including via geophysical imaging, borehole drilling, and rock testing; (2) quantify water transit times and chemical weathering reactions and fluxes, via groundwater dating, stream and spring monitoring, and reactive transport modeling; and (3) develop models of landscape evolution that account for the interconnected processes that regulate landslides, which are the primary vehicles for hillslope erosion in these settings. The project includes diverse opportunities for student education, development of international collaboration. A summer school for early-career researchers will expand the educational reach, and a short course on active source seismology will be held in Kathmandu to broaden the training opportunities for Nepali scientists.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.

山脉是地球表面最壮观的特征之一，但它们的重要性远远超出了它们上镜的性质。山脉在维持关键的自然资源方面发挥着关键作用，例如为大量人口提供淡水。山区是许多破坏性自然灾害的发源地，如山体滑坡和洪水。此外，山脉是新鲜岩石暴露在水和大气中的地方，导致化学反应，可以随着地质时间的推移改变二氧化碳和气候。这些过程都是紧密相连的，但它们在很大程度上是孤立地进行研究的。这个项目将在一个综合研究的范围内，研究岩石的物理和化学变化，以及水和地球材料的流动。该项目将在尼泊尔喜马拉雅山脉的一个山谷中研究这些过程，那里的地形从南部较为平缓的地形转变为北部的高山。将应用记录景观变化的性质和速度的尖端技术来确定山脉在地球系统中的作用。将开发说明所有这些过程如何相互作用及其产生的影响的模型，以预测未来的变化并将结果应用于其他地区。这项研究将涉及多名研究生和本科生研究人员的培训，并将涉及来自四个国家的研究人员之间的合作。地球构造板块之间的碰撞边界产生了戏剧性的山脉，产生了破坏性的自然灾害，以及控制地表环境的化学和物理交换。该项目将包括对四个相互关联的问题的多学科调查：(1)在构造活跃的山脉中岩石在折返过程中如何发生物理和化学变化；(2)活动造山带的陡峭山区地形是如何发展的，特别是对滑坡的作用是什么；(3)水如何从降水中进入地下，进入排干活跃造山带的溪流和河流；以及(4)化学风化作用如何取决于这些背景下的构造和气候条件。该项目将调查尼泊尔中部的Melamchi Khola山谷，那里从南到北的显著折返速率梯度提供了一个理想的机会，在碰撞构造的原型背景下记录构造、地形演化、侵蚀、水文和化学风化之间的系统级关系。这项研究将(1)通过地球物理成像、钻孔和岩石测试来表征从微米到千米的岩体；(2)通过地下水测年、溪流和泉水监测以及反应运移模型，量化水的传输时间、化学风化反应和通量；以及(3)开发景观演变模型，解释调节滑坡的相互关联的过程，滑坡是这些环境下山坡侵蚀的主要工具。该项目包括多样化的学生教育机会，发展国际合作。职业生涯早期研究人员的暑期学校将扩大教育范围，加德满都将举办关于活动震源地震学的短期课程，以扩大尼泊尔科学家的培训机会。这一奖项反映了国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。