Fluvial terraces of the Ambleve: a marker of the Quaternary river incision in the NE Ardennes massif (Western Europe)

The geomorphological analysis of the terraces of the Ambleve, an Ardennian subtributary of the Meuse, allows us to reconstruct eleven distinct levels (T1 to T11). Like those of most rivers draining the Ardennes massif, the Ambleve terrace profiles also converge in the upstream direction. Moreover, the Main Terrace complex, widely recognized in the Rhine and Meuse systems (including their major tributaries draining the Ardennes-Eifel massif), has also been identified in the Ambleve valley. However, the lack of terrace remnants in the similar to 10-km-long reach of the Quarreux gorge, combined with the knickpoint observed in the present-day long profile in this reach, leaves some uncertainty in the overall profile reconstruction. Despite the presence of a paleokarst filled by alluvial material in the lower Ambleve and diversely dated between similar to 0,5 and similar to 1 Ma, firm chronological data about the Quaternary evolution of the Ambleve are still lacking. Therefore, we base our discussion of the temporal evolution of the Ambleve incision on geometrical correlations with dated terraces of the Meuse downstream of Liege.