Insight into ice-ocean interactions during the Last Deglaciation revealed by iceberg ploughmarks identified on the continental shelf of the West Antarctic Peninsula

In order to predict future changes in the Antarctic Ice Sheet under anthropogenic climate change, it is essential that we understand how it
responded to past climatic changes. The Antarctic Peninsula is seen as a bellwether system for the wider Antarctic Ice Sheet and, as such, is an
ideal palaeo-glaciological study area. The timings of the retreat of the ice front in this area since the Last Glacial Maximum have been
extensively researched and the configuration of the major ice streams that drained the ice sheet on the Northern Peninsula is broadly known.
However, the ice-ocean interactions that occurred during this period remain poorly understood. The identification and analysis of iceberg
ploughmarks can provide information on the extent of past ice sheets and the morphology of their calving fronts; past calving regimes and
hence the dynamic behaviour of the ice sheet in the past and how this may have changed over time; and past ocean circulation. During a
Schmidt Ocean Institute scientific cruise to the Antarctic Peninsula, high resolution, multibeam acoustic data was acquired in a poorly mapped
area of the Bellingshausen Sea near the Ronne Entrance. Thousands of iceberg ploughmarks were identified on bathymetric maps produced
from this data. These scours were mapped and their morphological characteristics were recorded. Morphometric analyses were undertaken,
including quantitative investigations of length, depth, width and sinuosity, and the intensity and distribution of scours were also investigated.
The implications of these results for the morphology and dynamics of the ice sheet and ice-ocean interactions since the Last Glacial Maximum
are then discussed. The insights gained from this study will be used to help validate and constrain ice sheet models where these ice-ocean
interactions are not currently well represented.