Past ice stream and ice sheet changes on the continental shelf off the Sabrina Coast, East Antarctica

• Published in: Geomorphology
• Main Authors: Fernández, R., Gulick, S., Domack, E., Montelli, A., Leventer, A., Shevenell, A., Frederick, B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier B.V. 2018
• Subjects: East Antarctic Ice Sheet; Glacial geomorphology; Grounding zone wedges; Mega scale glacial lineations; Antarctic; East Antarctica; Moscow University Ice Shelf; Sabrina Coast; The Antarctic; Totten Glacier; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Iceberg*
• Online Access: https://doi.org/10.1016/j.geomorph.2018.05.020; https://repositorio.uchile.cl/handle/2250/169420

Our understanding of the response of the Antarctic ice sheet to climate and ocean changes requires the improvement of current ice-atmosphere-ocean models and the accurate determination of boundary conditions such as ice thickness and extent at key time intervals, so that satellite gravity observations and isostatic models can be adjusted. However, large portions of the Antarctic margin remain understudied or lack suitable data. One key area where data are lacking, is the Sabrina Coast portion of the East Antarctic Ice Sheet (EAIS) margin where the Totten Glacier, which has the largest ice discharge in East Antarctica, is accelerating, thinning and loosing mass at high rates. In this work, we present the results of the first geological and geophysical marine survey to the continental shelf offshore of the Dalton Ice Tongue and Moscow University ice shelf, east of the Totten Glacier. The data presented include multibeam swath bathymetry and multichannel seismic, focusing on the sea floor morphology and sedimentary section above a regional angular unconformity separating pre- and post-Miocene glacial strata. Sea floor scouring and iceberg keel marks on the outer shelf, associated with gullies on the upper slope indicate that ice expanded in the past and grounded ~5 km from the shelf edge at ~450–500 mbsl, extending ~155 km north of the current Moscow University Ice Shelf. A nearly 1000 m deep area in the inner-middle shelf, oriented NW with paleo-ice flow direction indicated by mega scale glacial lineations (MSGL) and drumlins, is interpreted as a cross shelf glacial trough. A series of geomorphic associations on the north-eastern side of the glacial trough includes glacial lobes, grounding zone wedges (GZW), glacial lineations and transverse ridges, which indicates slower ice, grounding line stabilization and collapse. These geomorphic associations are organized in 4 four sets representing different past ice-flow configurations reflecting changes in ice flow direction, grounding line position, location of fast and ...