Water Movement At The Base Of Ice Sheets

• Published in: Journal of Glaciology
• Main Author: Whillans, I. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1979
• Subjects: Earth-Surface Processes; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000030070; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000030070

Abstract Flat-surfaced subglacial lakes, such as those discovered by Oswald (1975), can form where basal sliding velocities are low. As the glacier moves onto a subglacial lake, its underside retains the shape of the vertical relief at the lake edge. Differential heat transfer from the lake into high and low points in the interface flattens the surface by extra melting of the downward projections or freezing in the high areas. A time of the order of 10 3 years is required to flatten the fluting, and the down-glacier part of a subglacial lake can be flat-surfaced if the glacier takes longer than some 10 3 years to traverse the lake. Such a slow traverse time is expected near ice-drainage divides, and it is there that flat-surfaced lakes were discovered by radar sounding.