Geomorphological evidence for fluvial change during the Roman period in the lower Rhone valley (southern France)

The hydrological and geomorphological dynamics of the lower Rhone river (so uthern France) are studied during the Roman period (2nd-1st centuries BC, 2 nd-3rd centuries AD). The crossing of archaeological and radiocarbon dating methods allow to study events at a pluridecadal to centennial scale. From the Avignon town to the delta, the 15 sites where Roman fluvial dynamics we re recorded show higher flooding frequencies, higher energy levels during f loods, rises in the marshes or groundwater levels, and/or active morphologi cal dynamics such as channel migrations from Ist century BC to 1st-2nd cent uries AD, with respect to the encircling periods. Although this fluvial cha nge does not reach the amplitude of great climatic events such as the Littl e Ice Age in the Rhone valley, we show that it is also perceived in other p arts of the catchment and could have a climatic origin. However, this event is not recorded in the immediate Mediterranean environment of the lower Rh one, so that the Rhone appears to efficiently transmit a foreign climatic c hange. (C) 2001 Elsevier Science B.V. All rights reserved.