SEDIMENTOLOGICAL PARAMETERS AND DATING OF POST-BARREIRAS SEDIMENTS FROM REGION THE COASTLINE

Abstract Although there is some work from the 80s, little is known about the origin and mechanisms of these sediment deposits Post-Barreiras. The aim of this work was to analyze the sedimentological parameters, particle size and morphology of grains of sand and dating of sedments. samples Post-Barreiras and beach sediments were collected, which were subjected to dispersion of clay and silt, using NaOH 0,1 mol L-1; the sand fraction was separated at intervals of 1/2 phi [Φ]. The morphology of the grain was analyzed through optical microscope. We used the dating of three samples by the method of Optically Stimulated Luminescence. Results indicate that the Post-Barreiras sediments they were deposited at high energy environment, presumably by a higher contribution of marine processes with possible aeolian reworkings. Beach front sediments showed characteristics of aeolian deposition. The dates determined that the deposition of Post-Barreiras sediments was from the late Pleistocene to Holocene epoch (from 6,950 to 85,350ka). The altitudinal position of Post-Barreiras sediments (40-150m) cannot be associated to any known sea elevation level, which then emerges the hypothesis of neotectonic processes promoting elevation.