A large West Antarctic Ice Sheet explains early Neogene sea-level amplitude

• Published in: Nature
• Main Authors: Marschalek, J. W., Zurli, L., Talarico, F., van de Flierdt, T., Vermeesch, P., Carter, A., Beny, F., Bout-Roumazeilles, V., Sangiorgi, F., Hemming, S. R., Pérez, L. F., Colleoni, F., Prebble, J. G., van Peer, T. E., Perotti, M., Shevenell, A. E., Browne, I., Kulhanek, D. K., Levy, R., Harwood, D., Sullivan, N. B., Meyers, S. R., Griffith, E. M., Hillenbrand, C. D., Gasson, E., Siegert, M. J., Keisling, B., Licht, K. J., Kuhn, G., Dodd, J. P., Boshuis, C., de Santis, L., McKay, R. M., Ash, J., Cortese, G., Esper, O. V., Gales, J. A., Ishino, S., Kim, Sookwan, Kim, Sunghan, Laberg, Jan Sverre, Leckie, R. M., Muller, J., Patterson, M. O., Romans, B. W., Romero, O. E., Seki, O., Singh, S. M., Cordeiro de Sousa, I. M., Sugisaki, S. T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Nature 2021
• Subjects: Antarctic; East Antarctica; Ross Sea; West Antarctica; West Antarctic Ice Sheet; Antarc*; Antarctica; Ice Sheet
• Online Access: https://hdl.handle.net/10037/24498; https://doi.org/10.1038/s41586-021-04148-0

This version of the article has been accepted for publication, after peer review and is subject to Springer Nature’s AM terms of use , but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at https://doi.org/10.1038/s41586-021-04148-0 . Early to Middle Miocene sea-level oscillations of approximately 40–60 m estimated from far-field records1,2,3 are interpreted to reflect the loss of virtually all East Antarctic ice during peak warmth2. This contrasts with ice-sheet model experiments suggesting most terrestrial ice in East Antarctica was retained even during the warmest intervals of the Middle Miocene4,5. Data and model outputs can be reconciled if a large West Antarctic Ice Sheet (WAIS) existed and expanded across most of the outer continental shelf during the Early Miocene, accounting for maximum ice-sheet volumes. Here we provide the earliest geological evidence proving large WAIS expansions occurred during the Early Miocene (~17.72–17.40 Ma). Geochemical and petrographic data show glacimarine sediments recovered at International Ocean Discovery Program (IODP) Site U1521 in the central Ross Sea derive from West Antarctica, requiring the presence of a WAIS covering most of the Ross Sea continental shelf. Seismic, lithological and palynological data reveal the intermittent proximity of grounded ice to Site U1521. The erosion rate calculated from this sediment package greatly exceeds the long-term mean, implying rapid erosion of West Antarctica. This interval therefore captures a key step in the genesis of a marine-based WAIS and a tipping point in Antarctic ice-sheet evolution