Increasing Ocean Access to Totten Glacier, East Antarctica

Tuesday, 16 December 2014
Jamin Stevens Greenbaum1, Donald D Blankenship1, Duncan A Young1, Alan Aitken2, Thomas G Richter1, Jason L Roberts3,4, Roland Charles Warner3,4, Tas D van Ommen3,4 and Martin John Siegert5, (1)University of Texas at Austin, Institute for Geophysics, Austin, TX, United States, (2)University of Western Australia, School of Earth and Environment, Crawley, WA, Australia, (3)University of Tasmania, Antarctic Climate & Ecosystems Cooperative Research Centre, Hobart, Australia, (4)Australian Antarctic Division, Kingston, Australia, (5)Imperial College London, Grantham Institute and Department of Earth Science and Engineering, London, United Kingdom
The Totten Glacier Ice Shelf (TGIS) is the primary outlet of the Aurora Subglacial Basin, draining 6.9 meters of eustatic sea level potential into the Sabrina Coast (SC) alongside the Moscow University Ice Shelf that fringes the coastline. The TGIS and surrounding grounded ice has the largest thinning signal in East Antarctica and the nature of the thinning suggests that it is driven by enhanced basal melting due to ocean processes. Warm Modified Circumpolar Deep Water (MCDW), which has been linked to glacier retreat in West Antarctica, has been observed in summer and winter on the SC continental shelf in the 400-500 m depth range. Here we show, using new data from recent aerogeophysical flights, that entrances to the cavity exist that are deeper than this range of thermocline depths, indicating that the TGIS is vulnerable to intrusions of MCDW if the vertical structure of cavity inflow is similar to the nearest observations. We provide evidence that a new entry to the cavity has opened likely due to the interplay between thinning ice and subglacial channels that could be related to regional mass loss acceleration observed in 2006. This new connection may increase access of warm water to the east side of the ice shelf, potentially destabilizing the low-lying area to the east of the TGIS.