Age limits on the late quaternary evolution of the upper Loire River

The Loire River is one of the largest rivers in Europe, draining a basin ar ea of southern France which exceeds 100,000 km(2). Despite its significance , the Loire remains poorly studied and has a very limited amount of chronol ogical control on the deposited sedimentary record of fluvial activity. The se factors, coupled with the availability of a set of 10 radiocarbon dates on younger (c., < 5 ka) Loire terraces, have encouraged us to commence an i ntensive programme of optical dating on terraces from the upper Loire. We h ave obtained relatively good agreement between single-aliquot regeneration (SAR)-based age estimates and AMS dates, and have extended the chronology o f the terraces back into the middle Weichselian. Our data indicate that the key shift in fluvial style from a braided gravel-bedded system through to a sand and silt dominated system occurred at around the time of the Pleisto cene-Holocene transition. (C) 2000 Published by Elsevier Science Ltd.