Abstract
Past glaciation is known to have caused a substantial morphological change to high latitude regions of the northern hemisphere. In the assessment of the long-term performance of deep geological repositories for radioactive wastes, future glaciation is a critical factor to take into consideration. This study develops a thermal-mechanical model to investigate ice sheet thermal evolution and the impact on bedrock erosion. The model is based on comprehensive field data resulting from international collaborative research on the Greenland Analogue Project. The ice sheet model considers surface energy balance and basal heat flux, as well as the temperature-dependent flow of ice that follows Glen’s law. The ice-bedrock interface is treated with a mechanical contact model, which solves the relative velocity and predicts the abrasional erosion and meltwater flow erosion. The numerical model is calibrated with measured temperature profiles and surface velocities at different locations across the glacier cross-section. The erosion rate is substantially larger near the glacier edge, where channel flow erosion becomes predominant. The abrasional erosion rate is averaged at 0.006 mm/a, and peaks at regions near the ridge divide. The mean meltwater flow erosion rate in the study area is estimated to be about 0.12 mm/a for the melted base region.
Highlights
Past glaciation is known to have caused a substantial morphological change to high latitude regions of the northern hemisphere
In the past million years, the Northern hemisphere was subjected to many glaciationdeglaciation cycles
The objective of this research is to further our understanding of the effects of glaciations on the THMC response of the geosphere, which could potentially host a deep geological repository (DGR)
Summary
Past glaciation is known to have caused a substantial morphological change to high latitude regions of the northern hemisphere. In the assessment of the long-term performance of deep geological repositories for radioactive wastes, future glaciation is a critical factor to take into consideration. This study develops a thermal-mechanical model to investigate ice sheet thermal evolution and the impact on bedrock erosion. The ice-bedrock interface is treated with a mechanical contact model, which solves the relative velocity and predicts the abrasional erosion and meltwater flow erosion. The mean meltwater flow erosion rate in the study area is estimated to be about 0.12 mm/a for the melted base region. In the past million years, the Northern hemisphere was subjected to many glaciationdeglaciation cycles. A DGR in Canada, or in similar Northern environments, would be subjected to the tremendous THMC perturbations that could potentially affect the structural integrity and performance of the multi-barrier system, reactivate fault zones near the DGR and erode the bedrock surface.
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