Sediment yield from glacio-lacustrine calcareous deposits during the postglacial period in the Combe d’Ain (Jura, France)

The middle valley of the river Ain (Jura) cuts through glacio-lacustrine deposits laid down in an ice-dammed lake during the most recent glacial advance. The total volume eroded is about 6·21 ×10 8 m 3 for a surface area of 3·7 ×10 7 m 2 . Erosion occurred between 18 ka BP and 6 ka BP, i.e. over a duration of some 12 ka. Sediment yield from the area was of the order of 2500 t km -2 a -1 , which is comparable with modern-day sediment yield from NW African badlands. These high values are ascribed to the amenability of glacio-lacustrine deposits to mechanical weathering and to the rapid geomorphological changes that affected glacial and paraglacial sedimentary cover after the retreat of the ic…