RABID

2004-9

Basal conditions on Rutford Ice Stream, West Antarctica: Hot water drilling and downhole instrumentation.

About the project

The vast majority of the ice in Antarctica is discharged through fast-flowing ice streams.

These form arteries through the ice sheet and, despite occupying only 10% of the coastline, discharge around 90% of the snow falling on the ice sheet in winter. Predicting the future of the world’s ice sheets and their impact on sea level requires an understanding of subglacial processes, as they are a key control on the flow of the ice streams.  

The RABID project, which is a collaborative initiative between the British Antarctic Survey and Swansea University, aims to improve predictions of the stability of the West Antarctic Ice Sheet during climate change. Specifically, the project aims to investigate the flow of a West Antarctic ice stream on timescales from hours/minutes to geologic times, and to elucidate the ice stream basal conditions and the role of these in controlling ice stream dynamics.

During the period 28th October 2004 to 28th February 2005, Professor Tavi Murray undertook fieldwork on the Rutford Ice Stream, West Antarctica. For almost three months she lived and worked 'deep field' in tents. Observations from the project show active processes beneath the ice stream that can normally only be postulated from the geological record. The observations show erosion at a rate of one metre per year beneath a fast-flowing Antarctic ice stream, followed by a cessation of erosion and the rapid formation of an active drumlin from fully mobilised sediment. Both mobilisation and increased compaction of basal sediment, interpreted as changes in quantity, location and pressure of water within the glacier bed, have been observed. All these changes have occurred on timescales of a few years or less. This degree of variability is far higher than expected. It shows that an ice stream can reorganise its bed rapidly and suggests that present models do not yet simulate all the relevant subglacial processes.