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: NE/V012037/1
• 负责人: Edward Tipper
• 金额: $ 31.13万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV012037%2F1
• 关键词: NSFGEO; NERC; Collaborative; Research; Coupling

The collision of continents driven by the movement of the Earth's tectonic plates raises the Earth's greatest mountain ranges. This has fundamental impacts on the habitability of large areas of the continents as well as controlling their geological evolution and moderating global climate. The prime modern example of a continental collision is the northward movement of India colliding with Asia which has raised the Himalayas and Tibet over the last 50 million years. This region sources freshwater for more than one-fifth of the global population and the floodplains of the rivers draining the region provide their food. The Himalayas and Tibet have a major impact on the climate of east and south-east Asia dominated by the summer monsoonal rains. The mountain range is the source of the major natural hazards in the region including earthquakes, landslides and floods. Continental collisions also have a major impact on the geological evolution the continental crust deforming, burying, heating and melting the crust and the associated uplift and erosion provides large amounts of sediment. The continental collisions are also thought to play an important part in moderating global climate on the greater than million-year timescales as the chemical reactions between carbon-dioxide dissolved in rainwater and the eroded sediment enhance the flux of dissolved carbon-dioxide and calcium to the oceans to be deposited as limestone removing carbon-dioxide from the atmosphere and limiting global temperatures.However the evolution of collisional mountain ranges involves complex interactions between tectonics, erosion and climate. The collision thickens the continents which elevates their surface topography, enhances erosion by landslides and the steeper river profiles. The topographic elevation also alters the local climate, for example by increasing rainfall which enhances erosion by increasing landslide frequency and the ability of rivers to transport sediments. The evolving topography of mountain belts is thought to represent a balance between the thickening of the continental crust by the collision balanced by the tendency of the thickened crust to spread under its own weight and the erosion of the crust forced by the topography and local climatic impacts. This project will study these complex interactions between the tectonic processes, the erosive processes dominated by landslides and the impact of climate by studying the Melamchi Khola river catchment in Nepal. The catchment spans the dramatic gradient in topography from the foothills to the high mountains, a gradient which is reflected by a marked increase in erosion rates towards the high mountains. The detailed study in one location will enable us to understand the interactions between the controlling processes. For example how does the exhumation rate control landslide formation and the erosion rate. How does the local climate, particularly rainfall, impact this relationship? How does removal of rock by erosion impact the controlling tectonics and propensity for earthquakes and landslides? The work will involve: 1) Determining how the physical and chemical properties of rock change by fracturing and chemical alteration as groundwater flows through the fractures as they are brought to the surface and the relationship of these changes to both the local tectonics and to climate. 2) Quantify how the topography is shaped by the competing processes of tectonically-driven uplift and erosion by landslides. How are these major processes impacted by the evolution of the rock mass and the groundwater flow through the subsurface. 3) Determine the flow paths of water as rain falls on the mountains and then enters fractured rock before feeding rivers below. 4) Quantify how the chemical alteration of the rock depends on the local climate (temperature and rainfall), groundwater flow paths and erosion rate.

由地球构造板块运动驱动的大陆碰撞抬升了地球上最大的山脉。这对大陆大片地区的宜居性以及控制其地质演化和缓和全球气候具有根本性影响。现代大陆碰撞的主要例子是印度向北移动与亚洲的碰撞，在过去的五千万年里导致了喜马拉雅山和西藏的上升。该地区为全球五分之一以上的人口提供淡水，流经该地区的河流洪泛区为他们提供食物。喜马拉雅山和西藏对东亚和东南亚以夏季季风雨为主的气候有重大影响。山脉是该地区主要自然灾害的根源，包括地震、山体滑坡和洪水。大陆碰撞也对地质演化产生重大影响，大陆地壳变形、掩埋、加热和熔化地壳，以及相关的隆起和侵蚀提供了大量沉积物。大陆碰撞也被认为在超过百万年的时间尺度上调节全球气候方面发挥着重要作用，因为溶解在雨水中的二氧化碳与被侵蚀的沉积物之间的化学反应增强了溶解的二氧化碳和钙到地球的通量。海洋以石灰石的形式沉积，消除了大气中的二氧化碳并限制了全球温度。然而，碰撞山脉的演化涉及构造、侵蚀和气候之间复杂的相互作用。碰撞使大陆增厚，抬高了其表面地形，加剧了山体滑坡和陡峭河流剖面的侵蚀。地形海拔也会改变当地的气候，例如，降雨量增加会增加滑坡频率和河流输送沉积物的能力，从而加剧侵蚀。山地带地形的演变被认为代表了由碰撞导致的大陆地壳增厚与地形和当地气候影响所迫使的地壳侵蚀之间的平衡，而该碰撞是由增厚的地壳在其自身重量下扩展的趋势所平衡的。 。该项目将通过研究尼泊尔的 Melamchi Khola 河流域来研究构造过程、以滑坡为主的侵蚀过程以及气候影响之间的复杂相互作用。该流域从山麓到高山的地形梯度很大，这种梯度反映在高山侵蚀率的显着增加上。在一个地点进行详细研究将使我们能够了解控制过程之间的相互作用。例如，折返率如何控制滑坡的形成和侵蚀率。当地气候，特别是降雨量，如何影响这种关系？通过侵蚀去除岩石如何影响控制构造以及地震和山体滑坡的倾向？这项工作将包括： 1) 确定当地下水流经裂缝到达地表时，岩石的物理和化学性质如何通过破裂和化学蚀变而发生变化，以及这些变化与当地构造和气候的关系。 2) 量化构造驱动的隆起和滑坡侵蚀的竞争过程如何塑造地形。这些主要过程如何受到岩体演化和地下地下水流的影响。 3) 确定雨水落在山上然后进入裂隙岩石然后注入下面河流时水的流动路径。 4) 量化岩石的化学变化如何取决于当地气候（温度和降雨量）、地下水流路径和侵蚀率。

项目成果

The efficacy of enhancing carbonate weathering for carbon dioxide sequestration

• DOI: 10.3389/fclim.2022.928215
• 发表时间: 2022-08-11
• 期刊: FRONTIERS IN CLIMATE
• 作者: Knapp, William J.;Tipper, Edward T.
• 通讯作者: Tipper, Edward T.