2018-2019 USAP Field Season
Geological history constraints on the magnitude of grounding line retreat in the Thwaites Glacier system
Dr. Brent M Goehring
Dr. Joanne Johnson
Supporting Stations: RV/IB Nathaniel B. Palmer
Researchers on this project hope to obtain geological evidence from the Thwaites-Pine Island Glacier system that will show whether glaciers were less extensive than they are at present, and, if so, when. Their goals are: (1) to determine whether previous grounding-line retreat-advance cycles, as suggested by existing geological evidence, occurred in the late Holocene; (2) establish under what climate and sea-level boundary conditions they took place; and (3) investigate whether this sector of the ice sheet collapsed during previous warm Pleistocene interglacial periods. Determining the conditions under which the Thwaites and Pine Island Glacier grounding lines have retreated and re-advanced in the past is critically relevant to determining whether or not present-day grounding-line retreat is irreversible.
Field Season Overview
Field work during 2018-19 will focus on producing a record of relative sea-level change from islands in Pine Island Bay. Two researchers will sail on the RV/IB Nathaniel B. Palmer (NBP) in late January to mid March and will coordinate with a seal tagging team (C-445-E/Heywood/Pettit) on the same cruise to conduct field research in the Edwards Islands. They may also conduct field work on other islands, if opportunities arise. Field work will consist of mapping raised beaches, collecting small samples of organic material for radiocarbon dating, and collecting rock samples for exposure-age dating. Samples will be shipped back to the University of Maine for analysis.
Deploying Team Members