USAP-DC

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Determining Middle Miocene through Pliocene Changes in Paleo Ice-flow and Basal Ice Conditions in East Antarctica through Sedimentological Analyses of Core Samples Description/Abstract This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The project aims on studying sediment cores collected from Prydz Bay and the Ross Sea to unravel the Neogene paleoclimatic history of the East Antarctic ice sheet. In the light of current measurements and predictions of a substantial rise in global temperature, investigations into the sensitivity of the East Antarctic ice sheet to climate change and its role in the climate system are essential. Geological records of former periods of climate change provide an opportunity to ground truth model predictions. The scientific objective of this project is to identify a previously proposed middle Miocene transition from a more dynamic wet-based East Antarctic ice sheet to the present semi-permanent ice sheet that is partially frozen to its bed. The timing and significance of this transition is controversial due to a lack of quantitative studies on well-dated ice-proximal sedimentary sequences. This project partially fills that gap using the composition and physical properties of diamictites and sandstones to establish shifts in ice-sheet drainage pathways, paleoenvironments and basal ice conditions. The results from the two key areas around the Antarctic continental margin will provide insight into the behavior of the East Antarctic ice sheet across the middle Miocene transition and through known times of warming in the late Miocene and Pliocene. Personnel Person Role Passchier, Sandra Investigator Funding Antarctic Earth Sciences Award # 0838842 AMD - DIF Record(s) NSF-ANT08-38842 Data Management Plan None in the Database Product Level: Not provided Datasets Repository Title (link) Format(s) Status USAP-DC Particle-size measurements for diamictites AND-2A sediment core, McMurdo Sound None exists Publications Pierce, E. L., van de Flierdt, T., Williams, T., Hemming, S. R., Cook, C. P., & Passchier, S. (2017). Evidence for a dynamic East Antarctic ice sheet during the mid-Miocene climate transition. Earth and Planetary Science Letters, 478, 1–13. (doi:10.1016/j.epsl.2017.08.011) Passchier, S., Hansen, M. A., & Rosenberg, J. (2021). Quartz grain microtextures illuminate Pliocene periglacial sand fluxes on the Antarctic continental margin. The Depositional Record. (doi:10.1002/dep2.157) Platforms and Instruments