GNGTS 2022 - Atti del 40° Convegno Nazionale

410 GNGTS 2022 Sessione 3.2 COOK GLACIER-OCEAN SYSTEM, SEA LEVEL AND ANTARCTIC PAST STABILITY (COLLAPSE) PROJECT: PNRA CRUISE 2022 PRELIMINARY DATA L. De Santis 1 , F. Accaino 1 , D. Accettella 1 , J. Beagley 2 , A. Bubbi 1 , E. Colizza 3 , F. Colleoni 1 , F. Coslovich 1 , D. Cotterle 1 , A. Cova 1 , L. Facchin 1 , A. Gallerani 4 , L. Gasperini 4 , D. Gei 1 , R. Gerin 1 , M. Giorgi 1 , V. Kovacevic 1 , P. Mansutti 1 , E. Mauri 1 , S. Picotti 1 , M. Petrini 1 , E. Pochini 1 , M. Santulin 1 , R. Scipinotti 5 , L. Ursella 1 , A.C. Vallejo 6 , F. Zgur 1 , P. Zuppelli 1 1 National Institute of Oceanography and Applied Geophysics – OGS, Sgonico, Italy 2 University of Otago, Dunedin, Nuova Zelanda 3 Dept. of Mathematics and Geoscience, Trieste University, Trieste, Italy 4 National Research Council –Marine Science Institute– CNR-ISMAR, Bologna, Italy 5 ENEA-UTA, Bologna, Italy 6 R&E Ocean Community Conservation Foundation, Oakville, ON, Canada The Cook Glacier drains most of the Antarctic ice sheet covering the Wilkes Subglacial Basin (WSB), with an ice volume equivalent to a global sea rise of approximately 3-4 m. In this area of ​Antarctica, the base of the ice sheet is below sea level, and consequently it is vulnerable to variations in ocean temperature. Long-term climate projections suggest that in this area of ​eastern Antarctica, hitherto considered colder and more stable, a rapid retreat of the ice sheet can be triggered in response to the intrusion of warm ocean waters (Circumpolar Deep Water, CDW). The disintegration of much of the ice shelf in front of the Cook in the 1970s and 1980s and the acceleration of the flow of ice in the eastern and inland areas of the WSB (2003-2007) could represent clues to the change in the balance of the system. However, neither the morphobathymetry of the continental shelf facing the Cook glacier, nor the present and past oceanography of the area is known. Therefore, it is not possible to know if there are or have been the conditions for the CDW to penetrate to the Cook grounding line. This information is essential for predicting the timing and modalities of the Cook glacier’s reaction to ocean warming in the coming decades. The COLLAPS (Cook glacier-Ocean system, sea LeveL and Antarctic Past Stability) project funded by the PNRA (National Research Program in Antarctica) aims to fill the lack of data and measurements in this area, about the current and past environment through amultidisciplinary geological, geophysical and oceanographic survey. During the PNRA campaign of 2022, the COLLAPSE project mapped in detail with the geophysical instrumentation (Multibeam, subbottom Topas, multi-channel seismic and magnetometer) present on board the research ice breaker L. Bassi, two systems of canyons and embankments located at the mouth of the glacial valleys of the Cook and of Ninnis. Sediment cores were collected on each of them with the aim of obtaining information on the rate of accumulation, the origin of the sediments and the different processes active on the seabed today and in recent periods. It will therefore be possible, albeit indirectly, to reconstruct the dynamics of the different glaciers as a function of climatic variations and ocean circulation and estimate their respective contribution to global sea level rise. During the COLLAPSE 2022 campaign, measurements of temperature, salinity, speed of currents and content of suspended biogenic material and on the seabed in the different areas of the embankment were also carried out. This information will be used to know the parameters that characterize the current environment, to be used as a reference guide to recognize similar characteristics in the geological record of the cores. Acknowledgements. We sincerely thank the Bassi’s Commander Sedmak, the crew members, the logisticians, the technicians and the researchers on board the Bassi who did their utmost to carry out the various activities envisaged by the project, We thank Flippo Muccino (INGV) for making the magnetometer available and for acquiring magnetic data in the COLLAPSE project area, which were not initially foreseen. Thanks to Paul Watcher, German Space Agency (DLR) for providing the Sentinel-1D and Sentinel-3 sea ice satellite images in addition to the AMSR2 satellite data available in ship, thanks to Stefano Ferriani (ENEA). Thanks to IHS for licensing the Kingdom interpretation software. Thank Amy Leventer (Colgate Univ. NY, USA) and Mauro Celussi (OGS) for providing all the material for the water filtering. Thanks to Pasquale Castagno (univ Partenope, Na), Dongseob Shin (KOPRI) and Craig Stevens and Philip Sutton (NIWA, NZ) who supplied us with XBT and XCTD