Graduation Year
2024
Document Type
Thesis
Degree
M.S.
Degree Name
Master of Science (M.S.)
Degree Granting Department
Marine Science
Major Professor
Alastair G. C. Graham, Ph.D.
Co-Major Professor
David F. Naar, Ph.D.
Committee Member
Anna Wåhlin, Ph.D.
Keywords
multibeam bathymetry, side-scan sonar, geomorphological map, glacier retreat, glacial landform, land system mode
Abstract
The future loss of ice in West Antarctica is one of the biggest uncertainties in projections of global sea level rise. The West Antarctic Ice Sheet (WAIS), home to Cosgrove Ice Shelf (CIS), contains enough ice to raise global sea level by more than three meters if it collapsed completely. Accurately predicting how much sea level change may occur from a future collapse of WAIS is of particular interest to low-lying, heavily populated coastal areas such as Florida. For this reason, it is important to understand the processes underpinning rapid changes and retreat at marine-terminating glaciers in the Amundsen Sea. At present, sub-ice shelf melting through warm water contact on the underside of the ice sheet is the central hypothesis for the changes occurring at the floating edges of marine-terminating glaciers like CIS. The grounding zone, the physical point at which the glacier meets the ocean and comes afloat, is of particular interest because it acts as a junction for ice, ocean, and solid Earth interactions. However, little is known about the processes that occur at grounding zones due to difficulties in collecting data in the direct vicinity of these ice sheets. Here we show new multibeam bathymetric and sub-bottom data, collected via an autonomous underwater vehicle (AUV), covering the seafloor of Ferrero Bay in front of CIS. These data provide high resolution bathymetry of the former ice bed and detailed observations of bedforms present in Ferrero Bay. We have identified several previous grounding zone wedges (GZW) and other features of interest. The AUV sub-bottom profiles illustrate evidence of both hard and soft substrate elements for this former ice bed – suggesting this could be classified as a mixed-substrate bed. Our results indicate that Cosgrove’s former ice bed is more complex than previously thought. The presence of several grounding zones and other mixed bedforms suggests that ice shelf retreat in Ferrero Bay was episodic during the Holocene.
Scholar Commons Citation
Burkhalter-Castro, Rosemary E., "Revealing Grounding Zone and Subglacial Processes at Cosgrove Ice Shelf: Seafloor Analogs for the Modern Antarctic Ice Sheet" (2024). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/10601
