Future hot water drilling on Rutford Ice Stream 2004/05

Ice streams are major drainage routes, through which much of the ice in Antarctica flows from the continent. They flow at speeds of up to two orders of magnitude greater that the rest of the ice sheet and are believed to rest on beds of soft, water-saturated sediments. As sliding and sediment deformation processes affect the ice stream dynamics, understanding them is essential to future predictions of ice sheet variations. Rutford Ice Stream provides one such example of a fast flowing glacier constrained by a deep bedrock trough and is one of a number of ice streams that drain the West Antarctic Ice Sheet into the southwestern Ronne Ice Shelf (Figure1). Extensive fieldwork has been conducted on this ice stream over the past 25 years with measurements of strain, velocity and elevation. Also, ice sounding radars and seismic techniques have been used to measure the ice thickness and examine the nature of the bed at several locations [Doake et al., 2001; Smith, 1997]. Many of these measurements have been made in an area approximately 40 km upstream of the grounding line. Here, the aim is to access the bed of Rutford Ice Stream at least twice through almost 2200 m of ice using a hot water drill. Ice cores will be retrieved from selected depths using a hot water ice core drill based on the Caltech design [Engelhardt et al., 2000] and samples of basal sediment will also be recovered. The hole will then be instrumented to measure basal sliding, bed and ice column deformation, basal water pressure and ice temperature. In situ optical images of the bed and any sediment within the ice may also be taken.

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