Characterisation of alteration profiles using dynamic penetrometry with variable energy. Application to weathered black marls, Draix (Alpes-de-Haute-Provence, France)

Characterisation of alteration profiles using dynamic penetrometry with variable energy. Application to weathered black marls, Draix (Alpes-de-Haute-Provence, France). A dynamic penetrometer with variable energy has been tested in a gullied catchment of Callovo-Oxfordian black marls (Draix, Alpes-de-Haute-Provence, France). After calibration and validation, simple convenient geotechnical criteria allow to interpret penetrograms in terms of type and thickness of layers in the weathered marl profile, with a centimetric precision: (1) the loose detrital cover, (2) the more or less compact regolith laying on (3) the marl bedrock. Once calibrated for a specific environment, this new prospecting method appears very useful, rapid and efficient to characterise shallow superficial formations and estimate their volume. (C) 2002 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.