LGM – Holocene sedimentary dynamics by multidisciplinary analysis of three box cores collected east to the Hillary Canyon (Eastern Ross Sea, Antarctica)

The presence of different types of glacial and sub-glacial features near the shelf edge indicates that the Western Antarctic Ice Sheet (WAIS) was grounded near the shelf break in many sectors of the Eastern Ross Sea (ERS) during the Last Glacial Maximum (LGM) (Shipp et al., 1999; Mosola & Anderson, 2006; Halberstadt et al., 2016; Anderson et al., 2018; Gales et al., 2021). However, mechanisms and timing of the post-LGM retreat are still debated. Studying sediments collected along the continental slope could help to reconstruct the LGM and post-LGM history of the ice sheet. This study focused on the analysis of three box cores collected east of the Hillary Canyon, which carves the ERS continental slope and is connected to the Glomar Challenger and Pennell Troughs on the shelf, south-east to the Iselin Bank. Multidisciplinary analysis (grain size, organic matter, biogenic silica and water content, magnetic susceptibility and chemical composition (XRF core scanner)) were conducted in order to reconstruct the sedimentary dynamics. Three samples for each box core were dated by using organic matter (14C AIO dates). Here, we present the results of these analysis. These box cores were collected during the XXIX PNRA (National Antarctic Research Program) expedition (2013-2014) and studied in the frame of the ROSSLOPE II (2013/AN2.01) PNRA project and the STREAM Project (Late Quaternary evolution of the ocean-ice sheet interactions: the record from the Ross Sea continental margin, Antarctica; period 2019-2021). The latter is funded by the Italian Ministry of Foreign Affairs and International Cooperation and the National Research Foundation of Korea. Anderson J.B., Simkins L.M., Bart P.J., De Santis L., Halberstadt A.R.W., Olivo E. & Greenwood S.L. (2018) - Seismic and geomorphic records of Antarctic Ice Sheet evolution in the Ross Sea and controlling factors in its behaviour. In: Le Heron, D.P., Hogan, K.A., Phillips, E.R., Huuse, M., Busfield, M.E. & Graham, A.G.C. Eds., Glaciated Margins: The Sedimentary and Geophysical Archive. Geological Society, London, Special Publications, 475, 223-240. Gales J., Rebesco M., De Santis L., Bergamasco A., Colleoni F., Kim S., Accettella D., Kovacevic V., Liu Y., Olivo E., Colizza E., Florindo-Lopez C., Zgur F. & McKay R. (2021) - Role of dense shelf water in the development of Antarctic submarine canyon morphology. Geomorphology, 372, 107453. Halberstadt A.R.W., Simkins L.M., Greenwood S.L. & Anderson J.B. (2016) - Past ice-sheet behaviour: retreat scenarios and changing controls in the Ross Sea, Antarctica. The Cryosphere, 10, 1003-1020. Mosola A.B. & Anderson J.B. (2006) - Expansion and rapid retreat of the West Antarctic Ice Sheet in Eastern Ross Sea: possible consequence of over-extended ice stream. Quat. Sci. Rev., 29, 2177-2196. Shipp S., Anderson J.B. & Domack E.W. (1999) - Late Pleistocene/Holocene retreat of the West Antarctic ice-sheet system in the Ross Sea. Part 1. Geophysical results. GSA Bulletin, 111, 1486-1516.