Les formations pliocenes des Alpes-Maritimes

Abstract

Abstract A stratigraphic and petrographic study of the Pliocene formations of Alpes-Maritimes, France, suggests that so-called Astian yellow clays and sands represent neither an independent stage nor a facies of the Plaisancian. They are consolidated muds, like the Plaisancian blue clays, that have been altered; the position of the water table determines the boundary between the two clay types. The fauna indicates that the clays represent deposition in shallow, near-shore zones. Tectonic activity prior to the upper Pliocene explains the abrupt change in sedimentation from deposition of fine Plaisancian elements to formation of the upper Pliocene conglomerates of both marine and continental derivation. Folds in the clays and conglomerates are evidence of the continuation of Alpine orogenic movements up to the beginning of the Quaternary.