USAP-DC

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. The Thwaites Glacier system dominates the contribution to sea-level rise from Antarctica. Predicting how this system will evolve in coming decades, and thereby its likely contribution to sea level, requires detailed understanding of how it has responded to changes in climate and oceanographic conditions in the past. 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. Specifically, the project will test the hypothesis--implied by existing geological evidence from the region--that present rapid retreat of the Thwaites Glacier system is reversible. The team aims to utilize two approaches: 1. To reconstruct relative sea level during the Holocene, it will map and date raised marine and shoreline deposits throughout Pine Island Bay. Chronological constraints on sea-level change will be provided by radiocarbon dating of organic material in landforms and sediments that are genetically related to past sea level, such as shell fragments, bones of marine fauna, and penguin guano. 2. To obtain geological evidence for past episodes of grounding-line retreat, the team will apply cosmogenic-nuclide exposure-dating of subglacial bedrock. Using drill systems recently developed for subglacial bedrock recovery, the team will 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. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Person	Role
Venturelli, Ryan A	Investigator and contact
Goehring, Brent	Investigator
Hall, Brenda	Investigator
Campbell, Seth	Investigator
Balco, Gregory	Investigator

Antarctic Earth Sciences	Award # 2317097
Antarctic Glaciology	Award # 2317097
Antarctic Earth Sciences	Award # 1738989
Antarctic Glaciology	Award # 1738989

USAP-1738989_1

Deployment	Type
Mt. Murphy	field camp
NBP1902	ship expedition

None in the Database

Repository	Title (link)	Format(s)	Status
R2R	NBP1902 Expedition data	Not Provided	exists
ICE-D	Cosmogenic-Nuclide data at ICE-D	Not Provided	exists
NERC EDS UK Polar Data Center	Cosmogenic 10Be data and calculated surface exposure ages for 41 cobbles and boulders collected from nunataks adjacent to Larter and Lucchitta glaciers in the Hudson Mountains, West Antarctica		exists
NERC EDS UK Polar Data Center	Geochronological data from the Hudson Mountains, Antarctica		exists
NERC EDS UK Polar Data Center	Laboratory spectral reflectance measurements at VNIR-SWIR wavelengths of 17 rock samples from Mount Murphy, West Antarctica		exists
NERC EDS UK Polar Data Center	Cosmogenic in situ 14C data and calculated surface exposure ages for 9 erratic cobbles collected from Mount Murphy, West Antarctica		exists
NERC EDS UK Polar Data Center	Orientations of bedrock striations in the Hudson Mountains, West Antarctica		exists
NERC EDS UK Polar Data Center	Geomorphological measurements and lithological classifications of 90 erratic cobbles from the Hudson Mountains, West Antarctica		exists
NERC EDS UK Polar Data Center	Cosmogenic Be-10 and Al-26 data and calculated surface exposure ages for cobbles collected from a moraine adjacent to Mount Murphy, West Antarctica		exists
NERC EDS UK Polar Data Center	Ground-penetrating radar surveys at three nunataks in the Hudson Mountains in the Amundsen Sea sector of West Antarctica, December 2019		exists
NERC EDS UK Polar Data Center	Cosmogenic Be-10 data and calculated surface exposure ages from nunataks adjacent to Pine Island Glacier in the Hudson Mountains, West Antarctica		exists
NERC EDS UK Polar Data Center	Beryllium-10 exposure ages for Pope Glacier from a scoria cone 1.5 km west of Mount Murphy in the Amundsen Sea Embayment		exists
USAP-DC	Pine Island Bay Relative Sea-Level Data	Excel	exists
USAP-DC	200 MHz ground-penetrating radar from Winkie Nunatak, West Antarctica	SEG-Y	exists
USAP-DC	In situ 14C data from a subglacial bedrock core near Pope and Thwaites glaciers	Excel	exists
USAP-DC	Ice-penetrating radar data from the northern embayment of the Mt. Murphy massif	Google Earth; HyperText Markup Language (HTML)	exists
USAP-DC	Firn and Ice Density at Winkie Nunatak	Microsoft Excel (OpenXML)	exists
USAP-DC	Ice-penetrating radar data from the Thwaites Glacier grounding zone	Not Provided	exists

1. Johnson, J. S., Venturelli, R. A., Balco, G., Allen, C. S., Braddock, S., Campbell, S., … Woodward, J. (2021). Review article: Existing and potential evidence for Holocene grounding-line retreat and readvance in Antarctica. The Cryosphere (doi:10.5194/tc-2021-360)
2. Balco, G., Brown, N., Nichols, K., Venturelli, R.A., Adams, J.R., Braddock, S., Campbell, S., Goehring, B., Johnson, J.S., Rood, D.H., Wilcken, K., Hall, B., Woodward, J. 2023. Reversible ice sheet thinning in the Amundsen Sea Embayment during the Late Holocene, The Cryosphere. First four authors contributed equally to this manuscript (doi:10.5194/tc-2022-172.)
3. Adams, J.R., Johnson, J.S., Roberts, S. J., Mason, P.J., Nichols, K.A., Venturelli, R.A., Wilcken, K., Balco, G., Goehring, B., Hall, B., Woodward, J., Rood, D.H. 2022. New 10Be exposure ages improve Holocene ice sheet thinning history near the grounding line of Pope Glacier, Antarctica, The Cryosphere. (doi:10.5194/tc-2022-82.)
4. Marschalek, J. W., Thomson, S. N., Hillenbrand, C.-D., Vermeesch, P., Siddoway, C., Carter, A., Nichols, K., Rood, D. H., Venturelli, R. A., Hammond, S. J., Wellner, J., & van de Flierdt, T. (2024). Geological insights from the newly discovered granite of Sif Island between Thwaites and Pine Island glaciers. Antarctic Science, 1–24. (doi:10.1017/s0954102023000287)
5. Braddock, S., Venturelli, R. A., Nichols, K., Moravec, E., Boeckmann, G. V., Campbell, S., Balco, G., Ackert, R., Small, D., Johnson, J. S., Dunbar, N., Woodward, J., Mukhopadhyay, S., & Goehring, B. (2024). Lessons learned from shallow subglacial bedrock drilling campaigns in Antarctica. Annals of Glaciology, 1–35. (doi:10.1017/aog.2024.12)
6. Nichols, K. A., Adams, J. R., Brown, K., Creel, R. C., McKenzie, M. A., Venturelli, R. A., Johnson, J. S., Rood, D. H., Wilcken, K., Woodward, J., & Roberts, S. J. (2024). Direct Geologic Constraints on the Timing of Late Holocene Ice Thickening in the Amundsen Sea Embayment, Antarctica. Geophysical Research Letters, 51(24). Portico. (doi:10.1029/2024gl110350)
7. Johnson, J. S., Woodward, J., Nesbitt, I., Winter, K., Campbell, S., Nichols, K. A., Venturelli, R. A., Braddock, S., Goehring, B. M., Hall, B., Rood, D. H., Balco, G. (2025) Assessing the suitability of sites near Pine Island Glacier for subglacial bedrock drilling aimed at detecting Holocene retreat and readvance. The Cryosphere 19, 303–324 (doi:10.5194/tc-19-303-2025)
8. Adams, J. R., Mason, P. J., Roberts, S. J., Rood, D. H., Smellie, J. L., Nichols, K. A., Woodward, J., Johnson, J. S. (2025) Remote mapping of bedrock for future cosmogenic nuclide exposure dating studies in remote unvisited areas of Antarctica. Remote Sensing 17 (2), 314. (doi:10.3390/rs17020314)
9. Jonson, J. S., Nichols, K. A., Riley, T. R., Venturelli, R. A., Hhodgson, D. A., Balco, G., Hall, B., Smith, J. A., Woodward, J. (2025) Glacial geology of the Hudson Mountains, Amundsen Sea sector, West Antarctica. Quaternary Science Reviews. (doi:10.1016/j.quascirev.2024.109027)
10. Walshaw, C.V., Gray, A., Fretwell, P.T., Convey, P., Davey, M.P., Johnson, J.S., Colesie, C. (2024) A remote-sensed baseline of photosynthetic life across Antarctica. Nature Geoscience 17, 755–762. (doi:10.1038/s41561-024-01492-4)
11. Nichols, K.A., Rood, D.H., Venturelli, R.A., Balco, G., Adams, J.R., Guillaume, L., Campbell, S., Goehring, B.M., Hall, B.L., Wilcken, K., Woodward, J., Johnson, J.S. (2023) Offshore-onshore record of Last Glacial Maximum-to-present grounding line retreat at Pine Island Glacier, Antarctica. Geology, 51, 1033-1037, paper (open access).
12. Herbert, L., Lepp, A.P., Munevar Garvia, S., Browning, A., Miller, L.E., Wellner, J., Severmann, S., Hillenbrand, C.-D., Johnson, J.S., Sherrell, R.M. (2023) Volcanogenic fluxes of iron from the seafloor in the Amundsen Sea, West Antarctica. Marine Chemistry, 104250, paper (open access) (doi:10.1016/j.marchem.2023.104250)