2021-2022 Antarctic

Geological History Constraints on the Magnitude of Grounding Line Retreat in the Thwaites Glacier System

This project contributes to the joint initiative launched by the U.S. National Science Foundation (NSF) and the U.K. Natural Environment Research Council (NERC) to substantially improve decadal and longer-term projections of ice loss and sea-level rise originating from Thwaites Glacier in West Antarctica. This project will provide a record of regional sea-level change by establishing chronologies for raised marine beaches as well as the timing and duration of periods of retreat of Thwaites Glacier during the past 10,000 years by sampling and dating bedrock presently covered by Thwaites Glacier via subglacial drilling. Together with climatic and oceanographic conditions from other records, these will provide boundary conditions for past-to-present model simulations as well as those used to predict future glacier changes under a range of climate scenarios. The project will utilize the Stampfli 2-Inch Drill and Winkie Drill to obtain subglacial bedrock from sites where ice thickness is dynamically linked to grounding-line position in the Thwaites system (specifically in the Hudson Mountains, and near Mount Murphy). Observation of significant cosmogenic-nuclide concentrations--the team will primarily measure Beryllium-10 and in situ Carbon-14--in these samples would provide direct, unambiguous evidence for past episodes of thinning linked to grounding-line retreat as well as constraints on their timing and duration.

Field Validation of ICESat-2 at Western Thwaites

Using the IDDO Hand Auger and Sidewinder, this project will measure firn density at three sites up to 40 meters deep along the Thwaites grounding zone. The project’s purpose is robust validation of the ability of ICESat-2 to estimate ice mass change at Western Thwaites, a rapidly changing ice shelf. One of the key challenges with understanding ice mass change is in understanding firn density. The fieldwork is a component of the Melting at Thwaites grounding zone and its control on sea level (MELT) project to measure the overall ice mass balance of Thwaites Glacier.