We open a 3 years PhD position at the Centre de Recherches Petrographiques et Géochimiques (CRPG, CNRS, Université de Lorraine, Nancy, France), mainly in the framework of the ERC Synergy Green2Ice project (2023-2029). This is a full-time position based at CRPG Nancy (supervision P.-H. Blard, pierre-henri.blard@univ-lorraine.fr), with a non-negligible period of time that will be spent in other European institutions for tight collaborations: Niels Bohr Institute of Copenhagen and Denmark Technical University (Danemark) and Université Libre de Bruxelles (Belgium, coll. F. Fripiat).

The main task of the PhD will be to get new key temporal constraints (duration and age) on the last partial deglaciation episodes of the Greenland (Green2Ice ERC project) and Antarctica ice sheets (ANR ToBe and Beyond EPICA H2020 projects) by using in situ cosmogenic nuclides of various half-lives (10Be, 26Al, 36Cl, 21Ne, possibly 41Ca) measured in the geological debris of the basal sections of the Greenland ice cores. The samples will be processed at the IRISS analytical platform of CRPG Nancy for 10Be, 26Al, and in the noble gas platform for 21Ne isotopes, while 36Cl will be undertaken in collaboration with I. Schimmelpfennig (CEREGE, Aix-en-Pce) and 41Ca in collaboration with Prof. Lu (China). Since there is not a unique solution to convert these isotopic ratios into past exposure scenario, the PhD student will perform forward numerical modeling to explore the most plausibile paleo-exposure scenarios, incorporating the luminescence data (OSL and IRSL) that are now obtained on the same geological ice core material analyzed in the frame of the Green2Ice project (Carlos ORTIZ, PhD 2024-2027, DTU Denmark, and Trine FREIESLEBEN Post Doc 2024-2027, DTU Denmark, Kristina THOMSEN, DTU Denmark). Luminescence dating and in situ cosmogenic nuclides are complementary methods because the former provide the age of the last deglaciation, will the later provide a maximum age and constrain the duration of this exposure.

The main targeted ice core basal material, will be: NewGRIP (drilling scheduled in 2026 and 2027), EastGRIP, NEEM and Camp Century as a test (interlab comparison and new isotopes in complement to the work of Christ et al., 2021; 2023) for Greenland (ERC Green2Ice project), and Byrd and Beyond Epica cores for Antarctica (ANR ToBe and Beyond EPICA H2020 projects).

This PhD will also have as a secondary side project, the characterization the geological nature of the debris incorporated in the basal ice of the Antarctic core, developing a variety of analytical methods (mineralogy, geochemistry) to characterize the formation age and the provenance of this material, in tight collaboration with the others scientists of our group working on the same material, notably Louise CRINELLA (PhD 2024-2027 CRPG Nancy).

We open a 3 years PhD position at the Centre de Recherches Petrographiques et Géochimiques (CRPG, CNRS, Université de Lorraine, Nancy, France), mainly in the framework of the ERC Synergy Green2Ice project (2023-2029). This is a full-time position based at CRPG Nancy (supervision P.-H. Blard, pierre-henri.blard@univ-lorraine.fr), with a non-negligible period of time that will be spent in other European institutions for tight collaborations: Niels Bohr Institute of Copenhagen and Denmark Technical University (Danemark) and Université Libre de Bruxelles (Belgium, coll. F. Fripiat).

The main task of the PhD will be to get new key temporal constraints (duration and age) on the last partial deglaciation episodes of the Greenland (Green2Ice ERC project) and Antarctica ice sheets (ANR ToBe and Beyond EPICA H2020 projects) by using in situ cosmogenic nuclides of various half-lives (10Be, 26Al, 36Cl, 21Ne, possibly 41Ca) measured in the geological debris of the basal sections of the Greenland ice cores. The samples will be processed at the IRISS analytical platform of CRPG Nancy for 10Be, 26Al, and in the noble gas platform for 21Ne isotopes, while 36Cl will be undertaken in collaboration with I. Schimmelpfennig (CEREGE, Aix-en-Pce) and 41Ca in collaboration with Prof. Lu (China). Since there is not a unique solution to convert these isotopic ratios into past exposure scenario, the PhD student will perform forward numerical modeling to explore the most plausibile paleo-exposure scenarios, incorporating the luminescence data (OSL and IRSL) that are now obtained on the same geological ice core material analyzed in the frame of the Green2Ice project (Carlos ORTIZ, PhD 2024-2027, DTU Denmark, and Trine FREIESLEBEN Post Doc 2024-2027, DTU Denmark, Kristina THOMSEN, DTU Denmark). Luminescence dating and in situ cosmogenic nuclides are complementary methods because the former provide the age of the last deglaciation, will the later provide a maximum age and constrain the duration of this exposure.

The main targeted ice core basal material, will be: NewGRIP (drilling scheduled in 2026 and 2027), EastGRIP, NEEM and Camp Century as a test (interlab comparison and new isotopes in complement to the work of Christ et al., 2021; 2023) for Greenland (ERC Green2Ice project), and Byrd and Beyond Epica cores for Antarctica (ANR ToBe and Beyond EPICA H2020 projects).

This PhD will also have as a secondary side project, the characterization the geological nature of the debris incorporated in the basal ice of the Antarctic core, developing a variety of analytical methods (mineralogy, geochemistry) to characterize the formation age and the provenance of this material, in tight collaboration with the others scientists of our group working on the same material, notably Louise CRINELLA (PhD 2024-2027 CRPG Nancy).