EUROFLEETS2 Funded Project “ANTSSS” Results

Project Acronym &Title: ANTSSS – Antarctic ice Sheet Stability from continental Slope Processes investigation

Area: Ross Sea, Antarctica

Research Vessel: R/V OGS Explora, OGS, Trieste, Italy

Chief scientist: Jenny Gales, National Oceanography Centre, UK; Paolo Stocchi, NIOZ, The Netherlands

Other project partners:&OGS, Italy; KOPRI, Rep. of Korea; CNR ISMAR, Italy; British Antarctic Survey, UK; Victoria University of Wellington, New Zealand; Alfred Wegener Institute, Germany; Florida State University, USA; IACT-CSIC, Spain; Norwegian Polar Institute, Norway.

Date: 17 – 25 February 2017

The main objective of the expedition was to collect new geophysical data from an underexplored area of the Ross Sea continental margin. Particular focus areas were deep-sea sediment mounds that form on the levees of the Hillary canyon on the continental slope and rise of the eastern Ross Sea. Sediment mounds are well known archives of continuous records of past glacial-to-interglacial fluctuations and by studying the mounds on the flanks of the canyon, the aims were to record the action of along and bottom-slope currents in order to understand how ocean currents and ice sheets have changed during Cenozoic glacial and interglacial cycles. A second focus area was the shelf edge and upper continental slope at the head of the canyon. By collecting data over this region, the aims were to better understand past and modern processes operating there. A final objective was to acquire geophysical data in these regions to constrain appropriate sites for future planned drilling as part of the International Ocean Discovery Program – Expedition 374 in 2018.

The EUROFLEETS2-ANTSSS expedition took place on R/V OGS Explora between February 17th – February 25th 2017 within the Italian PNRA-funded Antarctic cruise programme to the Ross Sea between January 18th and March 16th 2017. The designated survey areas were situated along the continental shelf edge and rise of the eastern Ross Sea, Antarctica, located between 178°W and 172°W.

During the expedition, 6 days of geophysical survey were conducted. This included collecting 453 km of single-channel seismic data over 6 main transects, including over sediment drifts on the canyon levees and parallel to the continental shelf edge. 1575 km2 of multibeam echosounder, subbottom profiler and ship-board Acoustic Doppler Current Profiler data were also collected, predominantly focused at the head of the Hillary Canyon. Here, preliminary results show submarine gullies and channels feeding the head of the canyon. Oceanographic data collection were also focused in this region, with 8 Conductivity Temperature Depth casts and 52 eXpendeble BathyThermographs deployed.

Overall, the data will help to constrain past and present processes operating along the eastern Ross Sea margin and at the head of the Hillary Canyon. Data processing and post-cruise analysis are currently underway and the initial results of the expedition will be presented at the European Geosciences Union conference 2017 and at the Past Antarctic Ice Sheet Dynamics (PAIS) 2017 meeting in Trieste, where the post-cruise workshop will also take place.