Geologic Reconstructions of Changes in Erosion Rates and Hillslope Processes in Response to Climate Forcing

景观综合了作用于地球表面的构造和气候驱动过程的影响。揭示地表过程的复杂动态对于理解景观如何应对气候变化至关重要，特别是在全球变化的背景下。通过重建与潮湿气候时期相关的侵蚀速率和山坡过程的过去变化，我们可以将过去和未来的气候变化与景观响应联系起来。在这项研究中，我将使用宇宙成因同位素来确定与过去潮湿时期有关的沉积矿床的古侵蚀速率。对相关地表过程的研究将包括量化土壤生产率，并注意沉积物来源和沉积物物理特性的任何变化。侵蚀速率将与现代侵蚀速率和长期地质剥露速率进行比较，以获取系统的长期平均行为和短期变异性。通过用实地数据校准数值模型，我将深入了解（1）不同景观对气候变化的敏感程度;（2）系统响应的性质，包括滞后时间、最大响应和达到新稳定条件的时间;以及（3）控制系统响应的过程。这种方法将使我们超越我们对降水增加导致更大侵蚀的定性理解，并进入预测气候变化对特定景观反应的领域。

Landscapes integrate the influence of tectonic and climate-driven processes acting on the Earth’s surface. Unraveling the complex dynamics of surface processes is crucial for understanding how landscapes respond to climate change, especially in the context of global change. By reconstructing past changes in erosion rates and hillslope processes associated with wet climate periods, we can link climate change with landscape response in the past and in the future. In this study, I will use cosmogenic isotopes to determine paleoerosion rates for sedimentary deposits associated with past wet periods. Studies of associated surface processes will include quantifying soil production rates and noting any changes in sediment provenance and physical characteristics of the sedimentary deposits. The erosion rates will be compared to modern erosion rates and long-term geologic exhumation rates to capture the long-term average behavior of the system and shorter-term variability. By calibrating numerical models with the field data, I will gain insight into (1) how sensitive different landscapes are to climate change; (2) the nature of the system response in terms of lag time, maximum response, and time to reach new steady conditions; and (3) the processes that control system responses. This approach will take us past our qualitative understanding that increased precipitation leads to greater erosion, and into the realm of predicting specific landscape responses to a change in climate.