SGER: Terrestrial in situ Cosmogenic Nuclides (TCN), Grain Size, and the Processes of Erosion

智力优势：使用陆地原位宇宙成因核素（TCN）已成为一种强有力的技术来量化地貌形成过程和计算侵蚀速率。冲积沉积物中的三氯化萘浓度可能取决于所取样的冲积颗粒大小。这导致计算正确的侵蚀率的问题，但也持有一个未充分利用的潜力，确定特定的山坡和通道风化和运输过程。本研究将使用TCN来量化岩石转化为风化层的山坡过程，风化层的运输渠道，并在运输过程中的粒度减小。这是及时的和有吸引力的，因为该技术正在享受广泛接受的不同社区的地球科学家。华盛顿州西部的奥林匹克山脉和爱达荷州东部的莱姆希山脉是多种多样的，但之前已经进行了充分的研究，以探索可变气候、构造和岩石类型对粒度- TCN浓度关系的影响。这项研究将对如何估计全流域冲积沉积物的侵蚀速率，确定侵蚀过程，空间分布，和坡面侵蚀速率，并在数值长期景观演变模型中分配各种侵蚀过程。结果将有重要的影响，在奥运会研究区的流域，有很强的使用压力的体育捕鱼，美洲原住民的鱼类捕捞和伐木的沉积物的渠道和生态系统管理。莱姆希山脉的研究将转化为地质野外营地项目，这是一个开创性的尝试，将过程地貌学融入夏季野外项目，这些项目在很大程度上是结构构造测绘练习的领域。博士的学术训练候选人帕特里克贝尔蒙特将得到支持。

Intellectual Merit: Use of terrestrial in situ cosmogenic nuclides (TCN) have emerged as a powerful technique to quantify landform-shaping processes and calculate rates of erosion. TCN concentrations in alluvial sediments can depend on the alluvial grain size sampled. This leads to problems in calculating the correct erosion rate, but also holds an underutilized potential for identifying specific hillslope and channel weathering and transport processes. This research will use TCN to quantify the hillslope processes of rock transformation into regolith, the transportation of the regolith to the channel, and grain size reduction during transport. It is both timely and attractive given that the technique is enjoying widespread acceptance by a diverse community of geoscientists. The Olympic Mountains of western Washington State and the Lemhi Range in eastern Idaho serve as diverse, but previously well-studied settings to explore the effects of variable climate, tectonics, and rock type on the grain size - TCN concentration relationship.Broader Impacts: The study will have immediate and important implications for how to estimate basin-wide erosion rates from alluvial sediment, identify the processes, spatial distribution, and rates of hillslope erosion, and apportion the various processes of erosion in numeric long term landscape evolution models. The results will have important implications for the delivery of sediment to channels and ecosystem management of the watersheds in the Olympics study area that have strong use pressures of sport fishing, Native American fish harvesting, and logging. The Lemhi Range study will be transformed into a geology field camp project which is a pioneering attempt to integrate process geomorphology into summer field programs that have largely been the domain of structure-tectonic mapping exercises. The academic training of a Ph.D. candidate, Patrick Belmont, will be supported.