HR: 1340h
AN: C43A-0223    [Abstracts]
TI: Radar Sounding Studies of Cracks at the Base of the Ross Ice Shelf, Antarctica
AU: * Smith, D E
EM: dcarver@mail.utexas.edu
AF: The University of Texas, Institute for Geophysics, Jackson School for Geosciences, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AU: Blankenship, D D
EM: blank@ig.utexas.edu
AF: The University of Texas, Institute for Geophysics, Jackson School for Geosciences, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AU: Peters, M E
EM: mattp@ig.utexas.edu
AF: The University of Texas, Institute for Geophysics, Jackson School for Geosciences, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AU: Morse, D L
EM: morse@ig.utexas.edu
AF: The University of Texas, Institute for Geophysics, Jackson School for Geosciences, 4412 Spicewood Springs Rd., Bldg. 600, Austin, TX 78759 United States
AB: Ice shelf systems are important links between ice sheets and global climate change. Through iceberg calving and basal melting and freezing, these ice shelves are vital contributors of fresh water to the thermohaline circulation of the world's oceans. In addition, as ice shelves evolve in concert with ocean circulation, the back stress that they provide to their parent ice sheet has been shown to modulate its evolution. The distribution and character of cracks beneath these ice shelves are important indicators of the evolving state of stress associated both with iceberg calving and grounding line migration. We will present results from airborne radar sounding surveys of the basal crack system from two locations on the Ross Ice Shelf. The first of these is iceberg B15a, representing a largely intact sample of 140 km of the calving front of the central Ross Ice Shelf. The second is a transect across the grounding zone where the now stagnant Kamb ice stream (ice stream C) abuts Siple Dome. Radar returns observed from basal cracks at these two locations are combined with dielectric models of crack evolution to classify cracks as either insipient or healed. The distributions of these classes of cracks at each site are interpreted from the perspective of the hypothesized stress states for ice shelf calving and grounding line retreat.
DE: 4540 Ice mechanics and air/sea/ice exchange processes
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 0694 Instrumentation and techniques
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting