Loess-palaeosol sections along the Rhône Valley in France are being studied to understand past climates. Luminescence dating is being used to determine the ages of these sediment layers. The researchers found that the loess deposits in southern France have been poorly dated in the past. They are now using optically stimulated luminescence (OSL) dating to establish accurate timelines for these sections. The brown palaeosol with carbonate concretions at the base of the last-glacial loess is a key feature, but it is often incomplete. By combining fieldwork observations with OSL dating, the researchers are making progress in reconstructing the environmental history of the Rhône Valley during the last glacial period.