Glacial history of the Maritime Alps from the Last Glacial Maximum to the Little Ice Age

Abstract

Abstract A complete sequence of glacial deposits and moraines within the same valley system in the Maritime Alps, spanning from the Last Glacial Maximum (LGM) to the Little Ice Age is presented. The sequence is geomorphologically and morphostratigraphically coherent and most stadials have been chronologically constrained by their cosmogenic exposure ages, lichenometry and by correlation with radiocarbon-dated moraines in neighbouring valleys. The shape, extent and thickness of the palaeoglaciers at each stadial have also been reconstructed and their equilibrium line altitude calculated. The LGM moraine of the Gesso Basin bears a similar equilibrium line altitude and age to that of other LGM moraines across the Alps. The recognized Late-glacial stadials show strong similarities with the corresponding stadials of the central–eastern Alpine valleys, such as Gschnitz, Bühl, Daun and Egesen. The recalculation of the exposure ages of moraine boulders with a new production rate better defines the LGM (24.0 ka) and the Egesen Stadial (13.0 ka), while the Bühl Stadial (18.5 ka) is dated for the first time in the Alps. Three early Holocene glacial advances are defined and correlated to the Kartell, Kromer and Göschenen I stadials, widely recognized in other Alpine sectors. Lichenometric dates indicate a three-fold oscillation during the Little Ice Age (thirteenth, seventeenth and nineteenth centuries).