Geothermal control on flow patterns in the last glacial maximum ice sheet of Iceland

Because it is located both on the Mid-Atlantic Ridge and on a mantle plume, Iceland is a region of intense tectonics and volcanism. During the last gl aciation, the island was covered by an ice sheet approximately 1000 m thick . A reconstruction of the ice flow lines, based on glacial directional feat ures, shows that the ice sheet was partly drained through fast-flowing stre ams. Fast flow of the ice streams has been recorded in megascale lineations and flutes visible on the currently deglaciated bedrock, and is confirmed by simple mass balance considerations. Locations of the major drainage rout es correlate with locations of geothermal anomalies, suggesting that ice st ream activity was favoured by lubrication of the bed by meltwater produced in regions of high geothermal heat flux. Similar control of ice flow by geo thermal activity is expected in ice sheets currently covering tectonically and volcanically active area such as the West Antarctic ice sheet. Copyrigh t (C) 2000 John Wiley & Sons, Ltd.