Spatially variable response of Antarctica's ice sheets to orbital forcing during the Pliocene

Authors

Molly P. Patterson, State University of New York Binghamton University
Christiana Rosenberg
Masanobu Yamamoto
Oscar Romero
Mei Nelissen
Francesca Sangiorigi
Nick Golledge
Georgia Grant
William Arnuk
Benjamin Keisling
Tim Naish
Richard Levy
Stephen Meyers
Nicholas Sullivan
Jeanine Ash
Denise Kulhanek
Brian Romans
Natalia Verela
Harold Jones
Francois Beny
Imogene Browne
Giuseppe Cortese
Isabela Cordeiro de Sousa
Justin Dodd
Oliver Esper
Jenny Gales, School of Biological and Marine Sciences
David Harwood
Saki Ishino
Sookwan Kim
Sunghan Kim

ORCID

• Jenny Gales: 0000-0003-4402-5800

Abstract

Variations in Earth’s orbit pace global ice-volume/sea-level changes, but the variability in the response for different sectors of the Antarctic Ice Sheet (AIS) to orbitally-forced climate change remains unclear. We present geological records of iceberg-rafted debris (IBRD) and other proxies from locations adjacent to the West Antarctic Ice Sheet (WAIS) and East Antarctic Ice Sheet (EAIS) spanning ~3.3-2.3 Ma. Iceberg calving events from the WAIS recorded in Ross Sea sediment cores show a linear response to orbital forcing at timescales corresponding to obliquity (40 kyr) and precession (23-19 kyr) modulated by eccentricity (100 kyr). This contrasts with records adjacent to the EAIS, which lack obliquity pacing. Geological data and ice sheet model sensitivity tests show the WAIS is highly dynamic and responsive to oceanic melt driven by changes in Southern Ocean circulation, together with atmospheric forcing through variations in local insolation. Conversely, the EAIS appears less responsive to oceanic forcing, despite being the dominant source of meltwater to the global ocean during the mid-Pliocene. Our results imply a significant role for atmospheric warming on mid-Pliocene sea-level.

DOI Link

10.21203/rs.3.rs-4837964/v1

Publication Date

2025-10-02

ISSN

1752-0894

Acceptance Date

2025-10-02

Embargo Period

2026-01-01

Additional Links

https://www.researchsquare.com/article/rs-4837964/v1

Recommended Citation

Patterson, M., Rosenberg, C., Yamamoto, M., Romero, O., Nelissen, M., Sangiorigi, F., Golledge, N., Grant, G., Arnuk, W., Keisling, B., Naish, T., Levy, R., Meyers, S., Sullivan, N., Ash, J., Kulhanek, D., Romans, B., Verela, N., Jones, H., Beny, F., Browne, I., Cortese, G., Cordeiro de Sousa, I., Dodd, J., Esper, O., Gales, J., Harwood, D., Ishino, S., Kim, S., & Kim, S. (2025) 'Spatially variable response of Antarctica's ice sheets to orbital forcing during the Pliocene', Available at: 10.21203/rs.3.rs-4837964/v1