83-5 Appalachian Pasts, Arctic Futures: Lessons from Frozen Critical Zones

Abstract:

Climate influences the evolution of Earth's critical zone by modulating temperature and moisture in rock and soil, which in turn control chemical and physical weathering and biota. However, due to the frequency of Quaternary climate shifts and the integrative nature of the critical zone, isolating and quantifying evidence for temperature control on long-term landscape evolution remains challenging. Here I will present data from both modern and ancient permafrost landscapes demonstrating the unique control that temperature exerts on hydrology, erodibility, and hillslope form in both the Arctic and mid-latitude sites adjacent to former ice sheets.

In Arctic landscapes, we show that hillslope flux from solifluction and inhibited incision from frozen ground together reduce drainage density and store carbon on permafrost hillslopes, and warming is likely to instigate channel network expansion and carbon release. I show that we can infer changes to thermal and hydrological conditions in the subsurface via satellite-derived vegetation indices, coupled with field observations of vegetation and temperature, allowing us to remotely monitor these critical zones. I connect the processes active on modern permafrost landscapes to the legacy of periglaciation south of the Laurentide Ice Sheet, where ancient critical zones can be reconstructed from cored sediments. I show that high regolith production from frost cracking and increased hillslope flux during thaw influence hillslope morphology and erosion rate, and that structurally controlled basins in Appalachia record ecological and landscape response to the Pleistocene-Holocene transition.

Geological Society of America Abstracts with Programs. Vol. 58, No. 5, 2026

doi: 10.1130/abs/2026AM-19384

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