Middle and Upper Pleistocene fluvial evolution of the Meurthe and Moselle valleys in the Paris Basin and the Rhenish Massif

The terrace systems of the River Meurthe (Me), and the River Moselle (M) downstream from the present Moselle-Meurthe confluence are composed of eight stepped alluvial terraces (Me8-M8 to Me1-M1), situated at less than 90 m above the modern floodplain Me0-M0. Morphological, mineralogical and petrographical studies evidence that the oldest five terraces (Me8-M8 to Me4-M4) were formed by the “Palaeo-Meurthe”, while the Upper Moselle flowed towards the Meuse valley. Downstream from the confluence, the three youngest alluvial terraces (Me3-M3 to Me1-M1) contain crystalline sediments from the Upper Moselle basin; they have been formed since the Upper Moselle capture, dated about 250-270 ka before present. IRSL and radiocarbon datings provide independent absolute age control for these post-capture terraces, which respectively correlate with the end of the Saalian (Me3-M3) and the Weichselian (Me2-M2 and Me1‑M1). The constant relative height of the terraces between France, Luxemburg and Germany gives evidences that there was no differenciated tectonic movements along the valley since at least the capture. A cyclic evolution scheme for the formation of the terraces is presented. The main gravel sedimentation occurred during cold periods (pleniglacial and late glacial phases), with a minor erosive period at the beginning of late glacial periods. Major incision occurs at the warm-to-cold transition.