Presentation
The mission of this LEFE project is to prepare the study of the Beyond EPICA – Oldest Ice core currently being drilled a few dozen kilometers from the French-Italian base of Concordia. It will focus on the processes leading to the formation of paleoclimate signals at the air-snow-ice interface, and thus to a better understanding of the paleoclimate proxies measured in the ice cores, both in the ice matrix and in the air bubbles.
It will be based on two short, hundred-meter cores drilled in 2017/2018 and in 2022/2023 in the drill zone.
Projet LEFE-IMAGO : 2022 – 2024
Participants : IGE (coordination) ; LSCE ; CEREGE ; CNRM ; GIPSA-lab
This LEFE project includes a major component to better understand gas trapping processes in which LSCE is involved notably for measurements of orbital tracers O2/N2 and δ18Oatm, of δ15N (N2) and rare gas isotopes. Air content and CH4 will be measured in Grenoble. All these measurements, together with data on seasonal-scale firn pumping, will be used to improve firn models (densification, impact of metamorphism on gas trapping).
LSCE is also involved in the study of post-depositional effects, particularly metamorphism, on water isotopes. In areas of low accumulation, such as Concordia and the Beyond Epica drilling site, these effects are particularly important.
Another part of PROXYNNOV will focus on cosmogenic 36Cl and 10Be, which could help date the BE-OI core if the loss of chlorine and therefore the initial 36Cl/10Be ratio can be sufficiently constrained at the BE-OI site. An evaluation of δ15N (NO3-) as a tracer of accumulation rate will also be carried out as part of this project.