Sub-glacial lakes in Antarctica

• Main Author: Pilkington, Stephen
• Format: Other/Unknown Material
• Language: English
• Published: University of Canterbury 2001
• Subjects: Antarctic; East Antarctic Ice Sheet; Vostok Station; Antarc*; Antarctica; Ice Sheet
• Online Access: http://hdl.handle.net/10092/14052

For over 30 years the presence of subglacial lakes under the East Antarctic ice sheet wete only surmised. The first documented lecord is probably from a senior aviation navigator with the Soviet Antarctic Expedition Of 1959 who noted the existence Of shallow snow surface depressions near to the Vostok Station (780288, 106048'E), which he likened to "lakes" (Robinson 1960). He observed the surface manifestations of the deeply buried lakes, which remain level and smooth because there is no friction between the bottom of the ice sheet and the lake water. In contrast, the surrounding aæa.s have a mugh and tilted surface because of the friction between the ice and bedmck on either side. The significance of this was not appleciated at the time. In 1963-1964, members of the 9th Soviet Antarctic Expedition, studying the thickness of the ice sheet, collected seismic traces adjacent to Vostok (Kapitsa 1998). Seismic surveying involves placing the seismic source (an explosive charge) and sensing apparatus (seismometers) 30m or so deep into the dense glacial ice. The explosion and resultant echo from below ale timed, and indicate the depth of ice to bedrock. Again, scientists at the time failed to recognise the subtle indications of a deeply buried body of water. During the late 1960's and 1970's detailed VHF radio echo soundings wele taken of the ice sheet. By sending VHF radio waves down into the ice, where they reflect off layers of contrasting electrical properties, the thickness of the ice can be obtained. By plotting the consecutive radar pulses obtained by moving horizontally, glaciologists can generate a picture of the ice sheet in cross section (Figure I). The advantage of radar is that it can be mounted on aircraft and information For over 30 years the presence of subglacial lakes under the East Antarctic ice sheet wete only surmised. The first documented lecord is probably from a senior aviation navigator with the Soviet Antarctic Expedition Of 1959 who noted the existence Of shallow snow surface depressions near ...