ASSESSING ARCTIC TIDEWATER GLACIER STABILITY USING DIFFERENTIAL BATHYMETRY IN KONGSFJORDEN, SVALBARD, NORWAY

Fjord bathymetry and glacial sedimentation processes are significant factors in the life cycle of Arctic tidewater glacier systems due to the influence of seafloor depth on glacier stability. Shallow water or areas with sufficiently high sediment accumulation help stabilize a retreating glacier while deeper waters accelerate the process. Glacial responses to a changing seafloor can provide valuable insight into the response of an Arctic tidewater glacier system to a changing climate.

The combined ice front of the Kronebreen and Kongsvegen tidewater glacier complex has undergone slow retreat since it last surged forward in 1948. Since 2011, significant ice loss has occurred and glacial retreat has accelerated as the terminus has moved into deeper waters. The 2014 Svalbard REU bathymetric survey used high and low frequency echosounding to map the fjord floor.

In recent years, the glacier complex has moved backwards along a shallow ridge running up the middle of the fjord into progressively deepening waters to the north and south of the ridge. Comparisons with earlier studies have also shown zones of significant sediment accumulation. One area of the 2009 survey found an old grounding line fan to be at a depth of 35m, while the 2014 survey mapped this area at a depth of 8m. Subglacial upwelling and sediment accumulation on the southern side of the glacier complex are highly active, producing an island within the last two years, and have helped stabilize the glacier near the shoreline.