HR: 1340h
AN: C43A-0218    [Abstracts]
TI: A revised inventory of Antarctic subglacial lakes
AU: * Siegert, M J
EM: m.j.siegert@bristol.ac.uk
AF: University of Bristol, Bristol Glaciology Centre, School of Geographical Sciences, Bristol, BS8 1SS United Kingdom
AU: Carter, S
EM: sasha@utig.ig.utexas.edu
AF: University of Texas at Austin, Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, 4412 Spicewood Springs Road, Austin, TX TX 78759 United States
AU: Tabacco, I
EM: ignazio.tabacco@unimi.it
AF: University of Milan, Department of Earth Sciences, via Cicognara 7, Milan, 20129 Italy
AU: Popov, S
EM: spopov@peterlink.ru
AF: Polar Marine Geological Research Expedition (PMGRE), 24 Pobeda str., St. Petersburg, 188512 Russian Federation
AU: Blankenship, D D
EM: blank@utig.ig.utexas.edu
AF: University of Texas at Austin, Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, 4412 Spicewood Springs Road, Austin, TX TX 78759 United States
AB: The locations and details of 145 Antarctic subglacial lakes are presented. Subglacial lakes can be identified on radio-echo sounding (RES) data from the recognition of three characteristics. First, the radio reflections from subglacial lakes are strong and typically 10-20 dB greater than from the ice-bedrock boundary. Second, the echoes have constant strength along the record track, which is indicative of an interface that is smooth on the scale of the radio wavelength. Third the reflections from a lake are very flat compared with the surrounding topography and have a slope which is around ten times, and in opposite direction to, the ice surface slope (which is required if the lake is in hydrostatic equilibrium). The revised inventory is based on a former catalogue of lake-type features (Siegert et al., 1996), which has been subsequently reanalysed, and three additional datasets. The first is from Italian RES of the Dome C region of East Antarctica, from which fourteen new lakes are identified. These data also show that, in a number of occasions, multiple lake-type reflectors thought previously to be individual lakes are in fact reflections from the same relatively large lake. This reduces the former total of lake-type reflectors by six, but also adds a significant level of information to these particular lakes. The second dataset is from a Russian RES survey of the Dome A and Dome F regions of East Antarctica, which provides evidence of eighteen new lakes and extends the coverage of the inventory considerably. The third dataset comprises three airborne RES surveys undertaken by the US in East Antarctica over the last five years, from which forty three new lakes have been identified.
UR: http://www.ggy.bris.ac.uk/ellsworth
DE: 9310 Antarctica
DE: 9604 Cenozoic
DE: 1827 Glaciology (1863)
DE: 0900 EXPLORATION GEOPHYSICS
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting