L'érosion hydrique dans les terrains peu résistants des Préalpes françaises du sud. Mesures et variables explicatives sur parcelles et bassins-versants

Measurements of the current erosion of certain soft rocks were conducted in a sector of the French Alpine foreland. A combination of tried and tested standard methods was used with a view to obtaining the most precise results possible. The results confirmed that a layer of between 0.5 and 1.0 cm is eroded annually in the Upper Bathonian and Callovo-Oxfordian black marls, the thickness (more than 1 500 metres) and extent of which make them the most common rock formation in this region. The other formations are also subject to considerable denudation, details of which are also given in the article. Observations reveal that, on bare ground, denudation is much greater on north-facing slopes (1.2 cm) than on south-facing slopes (0.5 cm), that the degree of slope has virtually no influence on erosion, and that, on the other hand, the angle formed by the slope and the dip of the layers causes marked differences between slopes, in a similar way to the effect of orientation. Finally, during the main pluvio-erosive events responsible for this denudation, it is the kinetic energy of the precipitation which plays the main role. On the other hand, the amount of erosion for this period is not found to be correlated with the prior state of the ground any more than it is with the runoff

Denudation · Erosion · Foreland basin · Geography · Geomorphology · Marl · Precipitation · Structural basin · Tectonics · Aeolian processes and effects · Geology · Groundwater and Watershed Analysis · Paleontology · Soil erosion and sediment transport