USAP-DC

Intellectual Merit: Evidence from the eastern Ross Sea continental shelf indicates that the West Antarctic Ice Sheet advanced and retreated during the last glacial cycle, but it is unclear whether the ice sheet advanced to the shelf edge or just to the middle shelf. These two end-member scenarios offer different interpretations as to why, how, and when the West Antarctic Ice Sheet oscillated. The PI proposes to acquire seismic, multibeam, and core data from Whales Deep, to evaluate the timing and duration of two advances of grounded ice to the outer and middle shelf of the Whales Deep Basin, a West Antarctic Ice Sheet paleo ice stream trough in eastern Ross Sea. Grounding events are represented by seismically resolvable Grounding Zone Wedges. The PI will collect radiocarbon dates on in situ benthic foraminifera from the grounding zone diamict as well as ramped pyrolysis radiocarbon dates on acid insoluble organics from open-marine mud overlying the grounding zone diamict. Using these data the PI will calculate the duration of the two grounding events. Furthermore, the PI will test a numerical model prediction that West Antarctic Ice Sheet retreat must have involved melting at the marine terminus of the ice sheet. Pore-water from the grounding zone diamict will be extracted from piston cores to determine salinity and δ18O values that should indicate if significant melting occurred at the grounding line. Broader impacts: The data collected will provide constraints on the timing and pattern of Last Glacial Maximum advance and retreat that can be incorporated into interpretations of ice-surface elevation changes. The proposed activities will provide valuable field and research training to undergraduate/graduate students and a Louisiana high-school science teacher. The research will be interactively shared with middle- and high-school science students and with visitors to the LSU Museum of Natural Science Weekend-Science Program.

Person	Role
Bart, Philip	Investigator and contact
Steinberg, Deborah	Investigator

Antarctic Earth Sciences

Award # 1246357

NBP1502
NBP1502B_Whales_Deep_Basin_1.1

Deployment	Type
NBP1502	ship expedition

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	NBP1502 YoYo camera benthic images from Ross Sea	None	exist
R2R	NBP1502 Cruise Geophysics and underway data	GeoTIFF; Excel	exist

1. Bart, P. J., Anderson, J. B., & Nitsche, F. ( 2017). Post‐LGM grounding‐line positions of the Bindschadler Paleo Ice Stream in the Ross Sea Embayment, Antarctica. Journal of Geophysical Research: Earth Surface, 122, 1827– 1844. (doi:10.1002/2017JF004259)
2. Bart, P. J., Mullally, D., & Golledge, N. R. (2016). The influence of continental shelf bathymetry on Antarctic Ice Sheet response to climate forcing. Global and Planetary Change, 142, 87–95. (doi:10.1016/j.gloplacha.2016.04.009)
3. Bart, P. J., Anderson, J. B., & Nitsche, F. (2017). Post-LGM Grounding-Line Positions of the Bindschadler Paleo Ice Stream in the Ross Sea Embayment, Antarctica. Journal of Geophysical Research: Earth Surface, 122(10), 1827–1844. (doi:10.1002/2017jf004259)
4. Majewski, W., Bart, P. J., & McGlannan, A. J. (2018). Foraminiferal assemblages from ice-proximal paleo-settings in the Whales Deep Basin, eastern Ross Sea, Antarctica. Palaeogeography, Palaeoclimatology, Palaeoecology, 493, 64–81. (doi:10.1016/j.palaeo.2017.12.041)
5. Danielson, M., & Bart, P. J. (2019). Topographic control on the post-LGM grounding zone locations of the West Antarctic Ice Sheet in the Whales Deep Basin, Eastern Ross Sea. Marine Geology, 407, 248–260. (doi:10.1016/j.margeo.2018.11.001)
6. McGlannan, A. J., Bart, P. J., Chow, J. M., & DeCesare, M. (2017). On the influence of post-LGM ice shelf loss and grounding zone sedimentation on West Antarctic ice sheet stability. Marine Geology, 392, 151–169. (doi:10.1016/j.margeo.2017.08.005)
7. Bart, P. J., & Kratochvil, M. (2022). A paleo-perspective on West Antarctic Ice Sheet retreat. Scientific Reports, 12(1). (doi:10.1038/s41598-022-22450-3)