New Data For Upper Pleistocene Glacial Fluctuations In The Aubrac Mountains (Massif Central, France)

Without numerical chronological milestones, the reconstructions of glacial fluctuations and palaeo-climuttic evolutions in the Massif Central proposed until today remain subject to many uncertainties. In order to better understand the spatio-temporal dynamics of the freezing of the Massif Central, the north-eastern fringe of the Monts d'Attbrac was chosen as the first study site, because the glacial heritages are numerous and well preserved. Two key sectors have been identified thanks to the coupling of photo-interpretation and geomorphological prospecting approaches in the field. The mapping of glacial and proglacial forms and formations and the litho-stratigraphic analysis of the associated deposits allowed us to redefine the extension of three stages of freezing: maximum glacial extension, a recurrence affecting a large part of the massif and a stage of Withdrawal. These results led to a digital dating campaign using terrestrial cosmogenic nuclides and optically stimulated luminescence of glacial and proglacial sediments. Currently underway, this campaign should make it possible to establish the absolute chronological framework of glacial fluctuations in the Aubrac Mountains, to he compared with environmental fluctuations recognized elsewhere. The approach will then he extended to the entire western mountainous facade of the Massif Central and in particular to the Cantal-Cezallier-Monts Dore-Artense complex. These results led to a digital dating campaign using terrestrial cosmogenic nuclides and optically stimulated luminescence of glacial and proglacial sediments. Currently underway, this campaign should make it possible to establish the absolute chronological framework of glacial fluctuations in the Aubrac Mountains, to be compared with environmental fluctuations recognized elsewhere. The approach will then be extended to the entire western mountainous facade of the Massif Central and in particular to the Cantal-Cezallier-Monts Dore-Artense complex. These results led to a digital dating campaign using terrestrial cosmogenic nuclides and optically stimulated luminescence of glacial and proglacial sediments. Currently underway, this campaign should make it possible to establish the absolute chronological framework of glacial fluctuations in the Aubrac Mountains, to be compared with environmental fluctuations recognized elsewhere. The approach will then be extended to the entire western mountainous facade of the Massif Central and in particular to the Cantal-Cezallier-Monts Dore-Artense complex.Reconstructions of glacial variations and palaeoclimatic records in the Massif Central remain ambiguous because of a lack of clear chronological milestones. In order to clarify glacial fluctuation dynamics in the Massif Central, we focus our study on the eastern flank of the Aubrac massif where numerous glacial landforms and sediments are well preserved. Two key areas have been identified using a combination of remote sensing and field investigations of the geomorphology. Subsequently, precise analysis of sedimentological cross-sections in valleys and surveys of glacial landforms and sediments have allowed us to highlight three glacial stages: the maximum ice extent, a significant recurrence and a final stage. These results enabled us to define a calibrated sequence of dates using terrestrial cosmogenic nuclides on glacial and proglacial sediments.