Relative sea-level data preclude major late Holocene ice-mass change in Pine Island Bay

Braddock, Scott, Hall, Brenda L., Johnson, Joanne S., Balco, Greg, Spoth, Meghan, Whitehouse, Pippa L., Campbell, Seth, Goehring, Brent M., Rood, Dylan H. and Woodward, John (2022) Relative sea-level data preclude major late Holocene ice-mass change in Pine Island Bay. Nature Geoscience. ISSN 1752-0894 (In Press)

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Official URL: https://doi.org/10.1038/s41561-022-00961-y

Abstract

The rapidly retreating Thwaites and Pine Island glaciers together dominate present-day ice loss from the West Antarctic Ice Sheet and are implicated in runaway deglaciation scenarios. Knowledge of whether these glaciers were substantially smaller in the mid-Holocene and subsequently recovered to their present extents is important for assessing whether current ice recession is irreversible. Here we reconstruct relative sea-level change from radiocarbon-dated raised beaches at sites immediately seawards of these glaciers, allowing us to examine the response of the earth to loading and unloading of ice in the Amundsen Sea region. We find that relative sea level fell steadily over the past 5.5 kyr without rate changes that would characterize large-scale ice re-expansion. Moreover, current bedrock uplift rates are an order of magnitude greater than the rate of long-term relative sea-level fall, suggesting a change in regional crustal unloading and implying that the present deglaciation may be unprecedented in the past ~5.5 kyr. While we cannot preclude minor grounding-line fluctuations, our data are explained most easily by early Holocene deglaciation followed by relatively stable ice positions until recent times and imply that Thwaites and Pine Island glaciers have not been substantially smaller than present during the past 5.5 kyr.

Item Type: Article
Additional Information: Funding information: This work is part of the “Geological History Constraints” project, a component of the International Thwaites Glacier Collaboration. We thank C. Beeler, N. Fenney, V. Fitzgerald, A. Fox, K. Hogan, J, Kirkham, E. Rush, UNAVCO, the Polar Geospatial Center, and the Captain and Crew of the R/V Nathaniel B. Palmer for assistance. This work was supported by the National Science Foundation (Grant OPP-1738989 – SB, BH, GB, MS, BG, SC) and the Natural Environment Research Council (Grant NE/S006710/1 and NE/S006753/1 – JJ, DR, JW). This is ITGC Contribution No. ITGC-050.
Subjects: F600 Geology
F800 Physical and Terrestrial Geographical and Environmental Sciences
Department: Faculties > Engineering and Environment > Geography and Environmental Sciences
Depositing User: Elena Carlaw
Date Deposited: 01 Jun 2022 14:56
Last Modified: 13 Jun 2022 14:15
URI: http://nrl.northumbria.ac.uk/id/eprint/49249

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