<div>Antarctic Specially Protected Area (ASPA) No. 143 Marine Plain in East Antarctica is valued for its “outstanding fossil fauna and rare geological features” (ATCM XXXVI 2013) but scientific evidence to guide its protection is sparse. The fragile Sørsdal Formation contains diverse marine vertebrate and invertebrate fauna, preserving a unique record of Antarctic environmental conditions in the Pliocene (Quilty et al. 2000). Strict permitting and access conditions are in place for the ASPA but evidence-based guidance for decision makers on how to assess the risks to the values of the ASPA is minimal. </div><div><br></div><div>We will present the results of geological mapping, aerial imagery collection, and field observations from Marine Plain to consider the impact of foot traffic and helicopter access to the ASPA and provide options for future monitoring and management. Surficial geology of the broader Vestfold Hills (a 400 km2 ice-free region in East Antarctica) was mapped at 1:2000 scale using aerial photos, satellite imagery, a digital elevation model, and field observations (McLennan et al. 2021, McLennan et al. 2022). From this regional-scale mapping, we show that the glacial sediments draping bedrock hills in Marine Plain are typical of the Vestfold Hills region and do not represent the vulnerable Sørsdal Formation or the thermokarst features considered unique to the ASPA. Polygons outlining recommended landing areas for helicopters in the Marine Plain ASPA were derived using a buffer around the Sørsdal Formation, lakes, away from the edge of steep bedrock slopes, and higher that the limit of Pliocene marine inundation. Our results show how foundational datasets like landform and geomorphology mapping can provide robust evidence to support informed ASPA management. </div><div><br></div><div>ATCM XXXIV, 2013. Measure 9. Antarctic Specially Protected Area No 143 (Marine Plain, Mule Peninsula, Vestfold Hills, Princess Elizabeth Land): Revised Management Plan</div><div>McLennan S. M., Haiblen A. M. & Smith J. 2021 Surficial geology of the Vestfold Hills, East Antarctica. First ed. Canberra, Australia: Geoscience Australia. https://pid.geoscience.gov.au/dataset/ga/145535</div><div>McLennan S. M., Haiblen, A.M. & Smith, J. 2022 Surficial geology of the Vestfold Hills, East Antarctica, GIS dataset. Canberra, Australia: Geoscience Australia. https://pid.geoscience.gov.au/dataset/ga/145536</div><div>Quilty P. G., Lirio J. M. & Jillett D. 2000 Stratigraphy of the Pliocene Sørsdal Formation, Marine Plain, Vestfold Hills, East Antarctica, <em>Antarctic Science</em>, vol. 12, no. 2, pp. 205-216. Presented at the SCAR Open Science Conference 2024

<div>Compared to its inherently unstable West Antarctic companion, the East Antarctic Ice Sheet (EAIS) as the largest ice mass on Earth, was long considered to react relatively robustly to external oceanic and/or atmospheric forcing. Many studies from recent years, however, revealed that ice masses in its marine-based portions such as the Wilkes and Aurora Subglacial Basins, which hold a potential sea-level equivalent of about 20 metres, may react just as sensitively. Currently, many outlet glaciers that connect into these deep hinterland basins are subject to significant ice flow acceleration and grounding-line retreat, hence may hint at potentially substantial ice losses in coming decades and centuries. Since those observations only cover a relatively short time period of several decades, it remains largely uncertain how the modern rapid changes in those sectors compare to ice sheet dynamics since the ice sheet’s last maximum extent some 20,000 years ago. Here, we report first results from newly acquired multibeam bathymetry, sediment echography and <em>in-situ</em> sediment core data from the Davis and Mawson Sea continental shelves, revealing major palaeo-ice stream troughs, grounding-line stabilization features, and extensive meltwater drainage systems. These new combined data will allow for establishing crucial spatiotemporal benchmarks for characterizing past ice sheet dynamics for these vulnerable EAIS portions, and with that deliver a needed framework for testing and validating palaeo-ice sheet models that ultimately aim at predicting their future response more reliably. Presented at the 29th International Polar Conference 'Dynamic Poles and High Mountain Environments'