A potential 2 millions year old ice core site

This project aims at characterizing the North Patch area, situated at ~10 km from the Concordia station and which potentially hosts 2 million years ice at its base.
Scientists aim to reconstruct the Earth climate during the Mid-Pleistocene Transition (MPT) which occurred between 1.2 and 0.8 million years ago and which corresponds to the appearance of the large glacial cycles with a period of 100,000 years. This is why the Beyond EPICA project was started in 2016, with the current phase running as a European H2020 RIA (2019-2026) to retrieve a 1.5 million year old ice at the Little Dome (LDC) site. With its low ice thickness, it is unlikely that the LDC site will go back more than 1.5 million years with a sufficiently high resolution (Chung et al., 2023a, b). It is even possible that the LDC site will only reconstruct the late part of the MPT (Chung et al., 2024).
This project aims at characterizing a site with even older ice (2 million years), a period during which the greenhouse gases concentrations were potentially as high as today. A potential candidate area, called North Patch, was identified but a detailed survey needs to be carried out to characterize the future ice core possible locations (Parrenin et al., 2017; Chung et al., 2023a, b). While several nations (Australia, Korea, USA) are interested by North Patch, Europe and France are in the best position to foster the geophysical characterization of this area.
We propose here a geophysical campaign and numerical modeling work to further constrain the glaciological properties of North Patch. The personal could be hosted at Concordia and mutualized with the Beyond EPICA personal as long as this project lasts.
The geophysical campaign is composed first of a ApRES radar equipment deployment (provided by BAS) which measures at every location the vertical compression of layers. This equipment requires to revisit the same sites after several years, to measures the vertical displacement of internal reflection horizons. The main objective is to evaluate if there is basal melting underneath the ice sheet. In addition, ApRES can detect climatic transition, an information which can be included in our numerical modeling work. The deployment of ApRES is rapid (under an hour to deploy and overnight unattended measurement per site) and only requires 1 operator. ApRES will be deployed during the season 2025/2026 and revisited in 2026/2027 and 2028/2029. The ApRES measurements will be coupled with GNSS measurements at the same time and at the same places.
The second part of the geophysical campaign consists in the deployment of a deep-looking profiling radar (provided by AWI/UCPH) during the season 2025/2026, which will allow to laterally image the internal horizons. It is the same type of radar equipment which was deployed at LDC in 2019 (Lilien et al., 2021).
The numerical modeling will use the geophysical information to constrain the ice flow and the age in the basal layer of the North Patch region. It will be similar to what was published in Chung et al. (2023a, b; 2024) but with updated geophysical data.
Chung, A., Parrenin, F., Steinhage, D., Mulvaney, R., Martín, C., Cavitte, M.G.P., Lilien, D.A., Helm, V., Taylor, D., Gogineni, P., Ritz, C., Frezzotti, M., O’Neill, C., Miller, H., Dahl-Jensen, D., and Eisen, O.: Stagnant ice and age modelling in the Dom C region, Antarctica, The Cryosphere, 17, 3461-3483, https://doi.org/10.5194/tc-17-3461-2023, 2023.
Chung, A., Parrenin, F., Mulvaney, R., and Eisen, O.: Could there be 2 million year old ice at North Patch near Dome C, Antarctica?, PAGES Mag, 31, 60-61, https://doi.org/10.22498/pages.31.2.60, 2023.
Chung, A., Parrenin, F., Mulvaney, R., Vittuari, L., Frezzotti, M., Zanutta, A., Lilien, D.A., Cavitte, M.G.P., and Eisen, O.: Age, thinning and spatial origin of the Beyond EPICA ice from a 2.5D ice flow model, EGUsphere, 1-21, https://doi.org/10.5194/egusphere-2024-1650, 2024.
Lilien, D.A., Steinhage, D., Taylor, D., Parrenin, F., Ritz, C., Mulvaney, R., Martín, C., Yan, J.-B., O’Neill, C., Frezzotti, M., Miller, H., Gogineni, P., Dahl-Jensen, D., and Eisen, O.: Brief communication: New radar constraints support presence of ice older than 1.5 Myr at Little Dome C, The Cryosphere, 15, 1881-1888, https://doi.org/10.5194/tc-15-1881-2021, 2021.
Parrenin, F., Cavitte, M.G.P., Blankenship, D.D., Chappellaz, J., Fischer, H., Gagliardini, O., Masson-Delmotte, V., Passalacqua, O., Ritz, C., Roberts, J., Siegert, M.J., and Young, D.A.: Is there 1.5-million-year-old ice near Dome C, Antarctica?, The Cryosphere, 11, 2427-2437, https://doi.org/10.5194/tc-11-2427-2017, 2017.