Collaborative Research: Probing the Role of Rock Type in the Evolution of Glacial Landscapes

该项目将调查岩石类型对冰川侵蚀的作用。 虽然了解冰川侵蚀的过程，但这项研究的意义在于解决岩石类型和岩体断裂程度对侵蚀速率和模式的控制。 侵蚀速率控制着沉积物向河流和海洋的输送，而侵蚀模式则决定着受冰川侵蚀的地形结构和山脉高度。 对比岩石类型的侵蚀率的测定，暴露在壮观的Kichatna山脉和阿拉斯加山脉的Denali地块的花岗岩核心和变质围岩，将完成使用三种先进的方法：4 He/3 He的磷灰石从冰川端壁和侧壁配置文件，宇宙成因的放射性核素浓度在现代落石和中碛，和Nd的出口流的沉积物。 现代和十年尺度的冰川速度将使用全球定位系统和存档的航空照片分析记录。 结果将综合使用冰川的数值模型，他们侵蚀的山谷，并在剩余的岩石内不断变化的热场。更广泛的影响，虽然它一直被公认的岩石类型应该影响侵蚀速率的各种地貌过程，这项研究将是新颖的，在其重点放在岩石类型的作用，并应突出工具包，现在可以解决这些问题。 该研究将成为一名博士生的重点，并将为初级PI正在开发的新4 He/3 He方法提供另一个测试平台。 研究结果将被纳入大学课程，并在大学和公共场所的公开讲座中，包括冰川过程在产生公众重新娱乐的景观中占主导地位的国家公园。

This project will investigate the role of rock type on glacial erosion. While the processes of glacial erosion are understood, the significance of this research lies in addressing the control of both the type of rock and the degree of fracturing of the rock mass on the rates and patterns of erosion. Erosion rates control sediment delivery to rivers and oceans, while erosion patterns dictate both the topographic architecture and the heights of mountain ranges being attacked by glaciers. Determination of erosion rates in contrasting rock types, exposed in the granitic cores and metamorphic country rocks of the spectacular Kichatna Range and Denali Massif of the Alaska Range, will be accomplished using three cutting-edge methods: 4He/3He in apatites from glacial headwall and sidewall profiles, cosmogenic radionuclide concentrations in modern rockfall and medial moraines, and Nd in the sediments of outlet streams. Modern and decadal scale glacial speeds will be documented using GPS and analysis of archived air photographs. The results will be synthesized using numerical models of the glaciers, the valleys they erode, and the evolving thermal field within the remaining rock.Broader impactsWhile it has long been acknowledged that rock type should influence the rates of erosion by a variety of geomorphic processes, this research will be novel in its focus on the role of rock type, and should highlight the toolkit now available to address such issues. The research will be the focus of one PhD student, and will provide another testbed for the new 4He/3He method being developed by the junior PI. The results of the research will be incorporated in college courses, and in public talks at both university and public venues, including national parks in which glacial processes have dominated in the producing the landscapes in which the public recreates.