Morphosedimentary dynamics of fluvial systems evolving in formerly glaciated settings are strongly influenced by glacial landforms and deposits. While much research on post-glacial landscape evolution has focused on high mountain regions, low mountain ranges like the Vosges have remained comparatively underexplored. This lack of research is astonishing since the southern Vosges exhibit significant glacial imprints, already documented as early as the 19th century, and fluvial landscape evolution subse-quent to the Last Glacial Maximum (LGM) in this area has been so far overlooked. The Cleurie catchment (~80 km²) is a first-order Moselotte tributary located at the heart of the formerly glaciated Vosges and is therefore of particular interest. ~40% of its catchment area are covered by glacial-related deposits and the current catchment’s upper part hosted large palaeolakes during the LGM due to the convergence of several valley glaciers. Whilst earlier studies almost exclusively focused on those glacial imprints, post-glacial fluvial overprinting was disregarded. This study thus aims to (i) evaluate how much fluvial processes have subsequently shaped the inherited glacial topography in the Cleurie and (ii) reconstruct the post-LGM fluvial evolution of the catchment.The combination of detailed geomorphological mapping based on field surveys and a high-resolution LiDAR-derived digital elevation model, morphometric analyses of the hydrographic network, and in situ measurement of the bed-surface grain-size reveals catchment-scale geomorphological transience. Various features including convex profiles and knickpoints/hanging valleys, as well as an along-stream increasing trend of bed-surface grain-size, point to incomplete fluvial adjustment since the onset of deglaciation. This is explained by a multi-faceted glacial legacy: (i) beheading of the former catchment’s upper part, (ii) upstream signal propaga-tion buffered at the valley outlet (i.e. Saut de la Cuve waterfall) and (iii) major glacial landforms strewn along the main valley. A sequential reconstruction focusing on the formation stages of glacial-related and fluvial morpho-sedimentary units is proposed, chronologically anchored by radiocarbon dating of lacustrine sediments around ~10.6–9.3 ka cal. BP. The latter suggests lake persis-tence into the Holocene and thereby supports the hypothesis of late fluvial readjustment. This study provides the first insights into post-LGM fluvial evolution in the Cleurie and highlights the key role played by glacial overprinting on fluvial morpho-dynamics, but also calls for further investigations in this catchment (i.e. timing of deglaciation) and in other formerly glaciated catchments of the Vosges.
Fuchs et al. (Mon,) studied this question.