NEW APPROACH TO FLINF PEBBLES WEATHERING IN PLEISTOCENE RAISED BEACHES DEPOSITS: CONTRIBUTION TO THE STUDY OF VAL DE SAIRE WAVE-CUT PLATFORMS (NORMANDY, FRANCE)

摘要

Recent works on pleistocene wave-cut platforms in Val de Saire (Noimandy, France) allowed to identify four stepped platforms, corresponding probably to the MIS 5e, 7, 9, 11 Alteration of the flint pebbles present in marine deposits has been studied as a mean for build a relative chronology A specific surface analyzer and a pore sizer have been used Results showed that alteration stages distinguished to the naked eye (cortex thickness) correspond to a measurable physical reality Alteration develops both towards the center of the flint and by increasing pore sizes into the cortex Flint alteration is then a good marker of relative age of platforms, which has contributed to validate altitudinal correlations in the studied area.