Highlights from Carnegie PhD Scholars’ Gathering 2022
Project Title: A new approach to ice-sheet history and landscape evolution in the Cairngorms, Scotland
Glaciers and ice sheets have grown and collapsed over several glacial cycles in Earth’s history and are an important indicator of past climate change. Most of our knowledge of glacier change relates to the most recent glacial cycle, but this was just one of many glacial cycles in Earth’s history. While much of the Earth’s surface was shaped at this time, there are parts of the Scottish landscape that survived ice cover over many glacial cycles; these sites offer the opportunity to investigate long-term glacier change. The evidence for this exists at the atomic level inside of rock formations near mountain summits in the Cairngorms. These “tors” are delicate towers of rock that survived glacial erosion because the ice here was frozen to its bed. The tors offer a unique opportunity to learn about the long-term history of ice cover and erosion in Scotland through the measurement of rare “cosmogenic nuclides” that accumulate in rock minerals that are exposed at the Earth’s surface. These accumulate when the tors are exposed to the atmosphere and therefore cosmic radiation, but stop accumulating and are lost to radioactive decay when the tor is covered by protective ice. Because some nuclides decay faster than others, we can extract information on exposure time, ice cover time, and erosion rates through investigation of their isotopic ratios.
For this project, we retrieved a 4-metre deep rock core through a tor on Ben Avon and will use the change in isotopic ratios with depth to understand the history of ice cover and landscape change in Scotland. We hope the methodologies developed through this work can build on our initial work (Sugden et al., 2018) to constrain landscape development and ice history in Antarctica.
Awarded: Research Incentive Grant
University: University of Edinburgh