Research

Geomorphology | Glaciology | Geochronology | Palaeoclimatology

My research focuses on the applications of cosmogenic-nuclide surface-exposure dating and ice-flow modelling. Using these techniques, I am able to constrain past changes in the geometry and dynamics of ice sheets. Ultimately, this improves our understanding of ice sheet response to climate, and provides analogues for modern and future ice loss.

Ice sheets can erode bedrock and deposit boulders at their margins. Surface-exposure dating allows me to measure how long ago these bedrock and boulder surfaces were revealed by a thinning and retreating ice sheet. With this information I can establish the vertical and horizontal extent of ice sheets at different times in the past.

These surface-exposure data provide constraints for ice-flow modelling experiments. Both time-dependent steady-state simulations and transient simulations enable me to investigate glacier dynamics under certain environmental conditions, and the response of glaciers to climatic and topography-induced perturbations.

PROJECTS

East Antarctic Ice Sheet and sub-Antarctic glacier mass change during the last few millennia
As part of the Securing Antarctica’s Environmental Future (SAEF) program, this project aims to improve our understanding of ice sheet and glacier fluctuations over the last few millennia in East Antarctica and on Heard Island, and to use models to help identify the forcings and controls responsible for these changes. This will allow us to extend the observational record of glacier and ice sheet changes in Antarctica back beyond the historic period, and attribute past and present changes in ice sheets to climate forcing.

Characteristics and controls of ice sheet loss on centennial timescales
The polar ice sheets are getting smaller at an accelerating rate in response to a warming climate, but modern observations are not yet sufficient to determine whether current ice sheet loss marks the start of irreversible retreat. Through a combination of geological approaches and numerical ice-flow modelling, this project expects to generate new knowledge on the rates and magnitudes of ice sheet loss, and the processes that will dictate the amount of ice loss in this century and beyond. A key focus is to better understand what drove and controlled rapid ice loss during The Holocene (see review paper).

iceTEA – Tools for Exposure Ages
Cosmogenic-nuclide surface-exposure data provide important constraints on the thickness, extent and behaviour of ice masses in the geological past. iceTEA is a suite of freely accessible numerical tools that I have produced, which are available as an online interface (ice-tea.org) and as MATLAB© code (GitHub). By using the tools it is hoped that users will be able to evaluate complex exposure histories, assess the reliability of exposure ages, explore potential age corrections, and better analyse and understand spatial and temporal patterns within their data. The website also features summaries of published articles that use the tools to reconstruct glacier and ice sheet history (Spotlight Studies).

Past behaviour of Transantarctic Mountain outlet glaciers
Research conducted during my PhD explored the behaviour of Skelton and Mackay Glaciers in the Transantarctic Mountains in the recent geological past. I investigated the long-term fluctuations in glacier geometry and basal conditions over the Late Cenozoic, and the response of these glaciers to climate drivers and topographic controls during deglaciation from the Last Glacial Maximum (~20,000 years ago).