Le régime du Rhône dans l'Antiquité et au Haut Moyen Age

Abstract

The variations of the Rhône alluvial plain, from lake Leman to the Mediterranean sea, between the 5th century BC and the Early Middle Ages, are analysed through pedology, sedimentology and geomorphology on several urban and rural archaeological sites. Separated studies of the upper, middle and lower parts of the valley reveal the consistency of the river behaviour and the importance of climatic factor during this period. Two major crisis affect the hydrologic system and the river beds during the Iron Age I and the Early Middle Ages. A relatively long hydrologic pause remained between the 2nd century and the 4th-5th century AD. However increasing floods happened in the upper and lower Rhône valley during the 1st century BC. and the 1st century AD. On the middle Rhône, this crisis is delayed between the beginnings of the 1st and 3rd century AD. The impact of these variations on the archaeological sites is examined.