Doctoral Dissertation Research: Quantifying the Geomorphic Importance of Pre-Existing Fractures to Rates of Landscape Evolution

本博士论文研究项目将考察构造断裂在多大程度上改变了景观演化的速率和样式。这些裂缝通常与构造板块的运动、岩石的断裂和/或火山的喷发有关。自1875年以来，科学家们已经知道这些裂缝会影响山谷随着时间的推移而加深和扩大，但仍然不确定的是裂缝的重要性。例如，基岩裂缝浓度加倍对山谷演化的影响是什么？博士生将考察两个山谷，约塞米蒂国家公园的图奥勒米草地和塞拉国家森林的莫诺凹地。这些山谷在岩石类型、气候和冰川史等大多数方面是相似的，但它们在裂缝集中和样式上却有着根本的不同。该博士生将量化构造裂缝对景观演化的重要性，以评估裂缝集中、方向和分布对这两种不同裂缝类型的影响。这个研究项目将有助于加强对地球表面如何随时间变化的理解，并将有助于改进数值模型，以更真实地代表这种演变。该项目将为与该博士生一起工作的5名本科生提供教育和培训机会。有关该项目的信息及其结果将通过约塞米蒂国家公园和约翰缪尔荒野的公众宣传来呈现。该项目应能产生实际效益，帮助那些从事模拟长期特定景观演变的人，对地质工程和水文地质学具有特殊影响。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。

This doctoral dissertation research project will examine to what extent tectonic fractures modify the rates and styles of landscape evolution. These fractures are typically associated with the movement of tectonic plates, the faulting of rocks, and/or the eruption of volcanoes. Scientists have known since 1875 that these fractures influence how valleys deepen and widen over time, but what remains uncertain is how important the fractures are. What, for example, is the effect of a doubling in the bedrock fracture concentration on valley evolution? The doctoral student will examine two valleys, the Tuolumne Meadows of Yosemite National Park and the Mono Recesses of the Sierra National Forest. These valleys are similar in most respects, such as rock type, climate, and glacial history, but they are fundamentally different in their fracture concentration and style. The doctoral student will quantify the importance of tectonic fractures to landscape evolution in order to assess the effects of fracture concentration, orientation, and distribution for both of these distinct fracture styles.This research project will contribute to enhanced understanding of how the surface of the Earth changes with time, and it will help refine numerical models to more realistically represent that evolution. The project will provide education and training opportunities for five undergraduate students who are working with the doctoral student. Information about the project and its results will be presented through public outreach in Yosemite National Park and the John Muir Wilderness. The project should yield practical benefits by assisting those engaged in modeling the evolution of specific landscapes over long periods of time, with special implications for geological engineering and hydrogeology. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.