It’s that time of year again! Everyone is scrambling to get their posters completed and printed before leaving for AGU, resorting to begging the library staff to stay open just a few minutes later. Even though we know AGU happens at the same time every year, and have plenty of time to prepare, there is inevitably a throng of anxious geoscientists vying for a spot on the printing waiting list the night before getting on the plane.

Nevertheless, I am excited to present my work on the deglacial history of the Ross Sea!



Here is the abstract:

Marine evidence of a deconvolving Antarctic Ice Sheet during post-LGM retreat of the Ross Sea sector

1Lindsay O. Prothro, 2Yusuke Yokoyama, 1Lauren M. Simkins, 1John B. Anderson, 3Wojciech Majewski, 2Masako Yamane, 4Naohiko Ohkouchi

1Department of Earth, Environmental and Planetary Science, Rice University; 2Atmosphere and Ocean Research Institute, University of Tokyo; 3Department of Environmental Paleobiology, Polish Academy of Sciences; 4Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology

Predictive models of ice sheet and sea level change are dependent on observational data of ice-sheet behavior for model testing and tuning. The geologic record contains a wealth of information about ice-sheet dynamics, with fewer logistical, spatial, and temporal limitations than are involved in data acquisition along contemporary ice margins. However, past ice-sheet behavior is still largely uncertain or contested due to issues with obtaining meaningful radiocarbon dates. We minimize bias from glacially-reworked carbon and limitations from unknown geomorphic context and uncertainty in sediment facies identification by using careful sedimentary analyses within a geomorphic framework, as well as selection of appropriate dating methods. Our study area, the Ross Sea sector of Antarctica, is the primary drainage outlet for ~25% of the continent’s grounded ice. During the Last Glacial Maximum, the low-profile, marine-based West Antarctic Ice Sheet (WAIS) and the steeper profile, largely land-based East Antarctic Ice Sheet (EAIS) converged in the Ross Sea to flow out to or near the continental shelf edge. Geomorphic and sedimentary data reveal that during their subsequent retreat to form the Ross Sea Embayment, the two ice sheets behaved differently, with the WAIS rapidly retreating tens of kilometers followed by extended pauses, while the EAIS retreated steadily, with shorter (decadal- to century-long) pauses. This behavior leads us to believe that the two ice sheets may have contributed diachronously to sea level. By acquiring accurate timing of grounding line retreat, we are able to calculate volumes of ice lost throughout deglaciation, as well as associated sea level contributions. In addition, we attempt to rectify the contradicting marine and terrestrial interpretations of retreat patterns from the Ross Sea continental shelf.

Time and location: Session C21E, Tuesday, 12 December 2017 08:00 – 12:20; New Orleans Ernest N. Memorial Convention Center – Poster Hall D-F, Poster #0319