First glacial chronology in Corsica (Western Mediterranean Sea) based on 10Be moraine dating: evidence of two glacier extents since the Last Glacial Maximum
Résumé
The timing of past glacier fluctuations is poorly constrained in Corsica (Western Mediterranean Sea). Although several glacial landforms and deposits were described, there are no absolute glacial chronology. We will present 19 new 10Be cosmic-ray exposure ages (CRE) of boulders collected from 4 moraines located in the area of the Bastani Lake (Monte Renoso, Northern Corsica). For the first time on a Mediterranean island, mountain glacier fluctuations are documented from moraine CRE for the Lateglacial Period. Two main glacier advances since the Last Glacial Maximum are identified. 12 boulders of three moraines dated between 14.98 ± 0.89 ka BP and 18.88 ± 1.04 ka BP reveal a glacier extent during the Oldest Dryas (Heinrich Stadial 1 - HS1). 5 boulders of one moraine dated between 12.13 ± 0.69 ka BP and 13.93 ± 0.79 ka BP are attributed to the Late Glacial–Younger Dryas transition. Results and associated past Equilibrium Line Altitude will be compared with those in the Mediterranean mountain ranges. Implications for regional climatic conditions will be discussed.