USAP-DC

Collapse of the West Antarctic ice sheet (WAIS) could raise global sea level by up to 3 meters, at a rate of up to ~1 meter per century, yielding major societal impacts. The goal of this project is to determine if such a collapse occurred in the recent past. This will include development of new geochemical tools to evaluate the sedimentary geologic record around the WAIS to evaluate WAIS behavior during past warm periods. The primary activities to be carried out by the research team are to: 1) characterize the chemistry and magnetic properties of sediments being discharged from different portions of the WAIS and use these properties to ?fingerprint? inputs from different sources on the continent; 2) measure these same properties in a marine sediment core to document major changes in the WAIS over the last 150,000 years. Determining if the WAIS has collapsed in the recent past can provide important information on WAIS potential to grow unstable in the future. The tools to be developed here can then be used on older records around the WAIS to examine the frequency of ice sheet instability in the past. The project will support a postdoctoral researcher as well as undergraduate students. This project will develop sediment provenance proxies to trace the sources of sediment discharged by the West Antarctic Ice Sheet (WAIS) to the continental rise. Specific questions to be addressed are: 1) the degree that sediment from different WAIS terranes can be geochemically and magnetically differentiated; 2) the ability of terrane provenance proxies to detect WAIS collapse in the late Quaternary. The WAIS erodes sediments from various West Antarctic geologic terranes that are deposited in adjacent drift sites. The geochemistry and magnetic properties of drift sediments reflect the tectonic and metamorphic history of their source terranes. Deglaciation of a terrane during WAIS collapse should be detectable by the loss of the terrane?s geochemical and magnetic signature in continental-rise detrital sediments. Continental shelf late-Holocene sediments from near the current WAIS groundling line will be analyzed for silt- and clay-size Sr-Nd-Pb isotopes, magnetic properties, and major-trace elements. The suite of cores includes the eastern Ross Sea to the northern tip of the Antarctic Peninsula and will establish provenance signatures of the Ross and Amundsen Provinces of Marie Byrd Land, Pine Island Bay, Thurston Island/Eight Coast Block, Ellsworth-Whitmore Crustal Block, and Antarctic Peninsula terranes. Many of these terranes have similar tectonic and metamorphic histories but Sr-Nd isotope data from detrital sediments suggest at least 3 distinct provenance signatures. An initial down core study of Ocean Drilling Program Site 1096 in the Bellingshausen Sea will be conducted to detect if the WAIS was unstable during the last interglacial period.

Person	Role
Anders, Carlson	Investigator and contact
Beard, Brian	Co-Investigator
Stoner, Joseph	Investigator and contact

Antarctic Earth Sciences	Award # 1443437
Antarctic Earth Sciences	Award # 1443268

USAP-1443437_1

None in the Database

Repository	Title (link)	Format(s)	Status
PANGAEA	Radiogenic isotopes of ODP Site 178-1096	None	exists
PANGAEA	Sand content of ODP Site 178-1096	None	exists

1. Golledge, N. R., Clark, P. U., He, F., Dutton, A., Turney, C. S. M., Fogwill, C. J., … Carlson, A. E. (2021). Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change. Geophysical Research Letters, 48(17). (doi:10.1029/2021gl094513)