Chronology of glacier retreat in the Arve Valley (Haute-Savoie, France) at the end of the last Ice Age

The end of the last Ice Age ( 19,000 to 11,700 years ago) was a period of rapid climatic and environmental changes. In the Alps, within a few thousand years, the glaciers went from their last maximum extent, covering the entire Alpine range and extending into the piedmont areas, to small mountain glaciers similar to those found nowadays. There remains considerable uncertainty regarding the chronology and retreat rates of the major Alpine glaciers, particularly in the Northern French Alps, which present a complex geography.

Figure 2. Schematic sketchs representing the main dated steps of the deglaciation of the Arve Valley.

As part of Quentin Portal’s PhD thesis, a team of researchers from ISTerre (Université Savoie Mont Blanc, Université Grenoble Alpes) and Biogéosciences (Université Bourgogne Europe) presents a new study on the chronology of the last deglaciation in the Arve Valley (Haute-Savoie, France). This valley is a key area for understanding the deglaciation of the Northern French Alps, as the Arve Glacier linked the Mont Blanc massif, the highest in the Alps (Mont Blanc, 4,806 m), to the Rhône Valley, into which one of the largest glaciers in the Alps flowed during the last Ice Age.

The chronology of the retreat of the Arve Glacier was established using the cosmogenic 10Be exposure age dating method on erratic and morainic boulders left during the glacier melt (Figure 1). This chronology was combined with a reinterpretation of the glacial geomorphology of the Arve Valley, incorporating fieldwork and the use of modern tools (LiDAR HD data, IGN).

The results (Figure 2) show that the thinning of the joined glaciers is thought to have begun around 17,600 years ago. The Arve and Rhône glaciers likely separated before 15,900 years ago, at which point a phase of rapid retreat of the Arve glacier occurred. The glacier then retreated as far as the present-day Chamonix valley less than 13,200 years ago. This new chronology of deglaciation in the Arve valley thus sheds new insights on the dynamics of deglaciation in the northern French Alps.


Figure 1. Examples of some sampled erratic and morainic boulders in the Arve Valley.


The full study is published in : Journal of Quaternary


References :

Coutterand, S. (2010) [Etude géomorphologique des flux glaciaires dans les Alpes nord-occidentales au Pléistocène récent : du maximum de la dernière glaciation aux premières étapes de la déglaciation]. PhD thesis, Université Savoie Mont-Blanc.

Dorthe-Monachon, C. (1986) [Contribution à l’étude de la morphologie glaciaire de la vallée de l’Arve (Haute-Savoie, France) — Essai de reconstitution paléogéographique]. PhD thesis, University of Lausanne.

Ivy-Ochs, S. (2015) Glacier variations in the European Alps at the end of the last glaciation. Cuadernos de Investigación Geográfica 41, 295–315.

Roattino, T., Crouzet, C., Vassallo, R., Buoncristiani, J.-F., Carcaillet, J., Gribenski, N. et al. (2022) Paleogeographical reconstruction of the western French Alps foreland during the last glacial maximum using cosmogenic exposure dating. Quaternary Research 111, 68–83.

Scientific contacts :

  • Quentin Portal – ISTerre, Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, Grenoble, France