New PhD opportunity in Luminescence Dating at the Liverpool Luminescence Laboratory

DEADLINE: 10 January 2020
TITLE: Ice response in the Andes (24-55 ºC) to climate variability of the Little Ice Age


1. Introduction

There is an urgent need to estimate the impact of climate variability on ice masses in the Andes as they provide important water resources for society. Since 2010, the most severe and long-lasting hydrological drought on record has persisted in the central Andes (Rivera et al. 2017), which was driven by cooling in the tropical Pacific Ocean and reduced snowfall over the Andes. Climate model projections predict warming temperatures and precipitation redistribution in South America due to shifting atmospheric patterns over the 21st century. This would reduce freshwater availability to millions of people in the Andes by enhancing ice retreat. However, we do not understand how resilient ice masses in the Andes are to centennial-scale climate variability. The satellite record that we use as training sets for understanding these processes are insufficient as they only cover a small magnitude of climate change in comparison with the projections for the 21st century. Thus, we need to use the deeper past (i.e. the last period of dramatic climate variability) to quantify the impacts on ice and water resources.

2. Project summary:

This project will reconstruct the former ice limits of the Little Ice Age (LIA) in the Andes to understand how resilient ice masses are to centennial-scale climate variability. Previous studies have mapped the suggested LIA ice limits of the Northern and Southern Patagonian Icefields (e.g. Glasser et al. 2011; Rivera et al. 2012), but the limits between 24-55°S are largely unstudied and undated. Glacial geomorphological mapping of the high Andes will identify potential sites for field sampling. A combination of luminescence and cosmogenic nuclide dating will be used in this study to understand the timing of ice extents and infer any spatial variability between latitudes.

Luminescence dating is a technique important for reconstructing past environments on Earth over the last million years (see Smedley, 2018 for details). Routine luminescence dating of sedimentary grains (e.g. sand; Smedley et al. 2016) will be used to determine the timing of sediment deposition, alongside new developments in the technique that use rocks for burial dating. Cosmogenic nuclide dating is a technique routinely used to determine the time elapsed since erratic boulders or bedrock at ice margins were exposed. The ice reconstruction dataset developed can then be used in the latter stages of the project for data-model integration experiments, including process modelling experiments (supervised by Dr James Lea).

This project will use state-of-the-art equipment housed within the Liverpool Luminescence Laboratory (led by Dr Smedley), and the Cosmogenic Isotope Laboratory at the Pontificia Universidad Católica de Chile, Santiago, Chile (led by Dr Geiger) during a research visit. The University of Liverpool also hosts high performance computing facilities for modelling.

3. Supervisors and contact:



3. References:

Glasser et al. 2011. Global sea-level contribution from the Patagonian Icefields since the Little Ice Age maximum. Nature Geoscience, 4, 303–307.

Rivera et al. 2012. Little Ice Age advance and retreat of Glaciar Jorge Montt, Chilean Patagonia. Climate of the past, 8, 403–414.

Rivera et al. 2017. Regional aspects of streamflow droughts in the Andean rivers of Patagonia, Argentina. Links with large-scale climatic oscillations. Hydrology Research 49, 134-149.

Smedley 2018. Dust, sand and rocks as windows into the past. Elements, 14 (1), 9-14.

Smedley et al. 2016. Luminescence dating of glacial advances at Lago Buenos Aires (~46 °S), Patagonia. Quaternary Science Reviews, 134, 59 – 73.