ANTIPODE

FRAMEWORK:

• Context - Antarctic ice shelves are thinning in response to on-going ocean warming especially in the marine-based sectors of the Antarctic ice sheet (AIS):

Location of ocean heat exchanges across the continental shelf edge nowadays determines which sectors of Antarctica are most at risk of fast retreat or collapse.

• Evidence - Pan-Antarctic continental margins evolved notably since 34 Million years ago as result of the AIS advances and retreats and associated extensive bed erosion:

Sediment core records and seismic stratigraphy show a major change in sedimentation after the Middle Miocene (15 Million years ago) which affected the morphology of the bathymetry.

• Hypothesis - At some point of the Antarctic Ice Sheet evolution, the heat and salt exchange across the continental shelves become a first order factor of the Antarctic Ice Sheet variability. We want to determine when this feedback between ocean and Antarctica strengthened.

• Focus - Ross Sea continental shelf (Antarctica)

• Goal - Provide hints on past AIS tipping points during policy-relevant times of high atmospheric CO2 concentration, with a special attention to Middle-Miocene.

• Multi-disciplinary approach:

Ocean and ice-sheet modeling

Seismic stratigraphy (PNRA and international geophysics cruises)

Sedimentology (IODP exp. 374 ; PNRA past cruises)

Oceanographic data (PNRA campaigns)