Thwaites Glacier Margin Changes

Examining ice flow history of Thwaites Glacier using airborne radar and remote-sensing.

Ice-flow history of Thwaites Glacier, West Antarctica

Project Goals: This project has a sharply focused scientific goal: to understand the response of Thwaites Glacier to recent changes at its grounding line within the context of any possible long-term variability in mass balance. To this end, we concentrate on understanding the controls on fast glacier flow in this area and search for evidence which allows us to quantify the effect of recent changes in elevation and grounding line retreat on margin position within the context of longer time-scale retreat. Our plan is to work with data from groups that have previously visited the region (UTIG and ITASE) and those that are planning upcoming surveys (as part of ICEBridge) for analysis which allows us to test the following hypotheses related to our goal:

Margin migration: Observed changes in grounding line position and ice sheet elevation of Thwaites Glacier have forced outward migration of its lateral margins over the past few decades indicating that the basal boundary conditions that permit fast flow are not fixed in space and time.

Past variability: The divide between Thwaites and Pine Island Glaciers contains stratigraphy indicating that bounding glaciers have been active but fixed spatially for several millenia.

Controls on fast flow: A layer of deformable, wet till (as measured by increased bed reflectivity)
underlies the fast-moving trunk regions of Thwaites Glacier but not beneath the slow-moving
ridge between Thwaites and Pine Island Glacier. This wet till permits fast flow within the
trunk region.