Contenu du sommaire

Abstract. — A flattened larch trunk has been found in sands lying in the middle of the Quaix-Proveysieux cirque, 485 m above sea level, on the Southern side of the Chartreuse massif. From the sedimentological data its deposition can be placed during the recessional fluctuations of the local glacier, after an important erosive phase. Radiocarbon age (> 35.000 years) places these fluctuations during the Wurmian II, before the Wurmian II-III Interstage. The presence of these loose sediments at the center of the small valley rules out a new important glaciation, as they would otherwise have been scraped off; therefore, the Wurmian glacial maximum should antedate the Wurmian III in this part of the Alps.

Abstract. — The valleys observed have a very characteristic glacial relief, well preserved on Permian schists, conglomerate and sandstones. The detail's shapes express lithographies disparities and tectonics lines. The observation of little terminal moraines and rock-glaciers which fill place on the lower part of slopes or on glacial cirques let to put in evidence three principals phases of Late-glacial.