HR: 1340h
AN: C13B-1071    [Abstracts]
TI: Subglacial lakes in Iceland. A review.
AU: * Bjornsson, H
EM: hb@raunvis.hi.is
AU: Palsson, F
EM: fb@raunvis.hi.is
AB: Subglacial lakes in Iceland are expressions of glacier-volcanic interaction. At several of the central volcanoes under the ice caps Vatnajokull and Myrdalsjokull hydrothermal activity results from the interaction of water with magmatic intrusions at shallow depths in the crust. Ice is continuously melted at the glacier bed creating permanent depressions in the glacier surface that reveal this hydrothermal activity. The meltwater may be trapped in a lake that rises as a dome above the bed due to relatively low basal fluid potential under the depression. High ice overburden pressure at the rim around the depression seals the lake that expands as water flows toward the depression, until the hydraulic seal is broken and water drains out in a jokulhlaup. The best-known examples of such subglacial lakes are Gr¡msvotn in the interior of Vatnajokull and the Skafta cauldrons. We describe the geometry, refill rate, mass and energy balance of these subglacial lakes.
DE: 0720 Glaciers
DE: 0776 Glaciology (1621, 1827, 1863)
SC: Cryosphere [C]
MN: Fall Meeting 2005