Morphodynamics and chronology of quaternary aeolian depositional systems in Brazil

Abstract

This project aims to establish the stratigraphic and cronological framework of aeolian depositional systems in the Quatemary of Brazil. To this scientific purpose, two methodological goals are associated. The first one consists in contribute to application, development and diffusion, in Brazil, of new procedures of dating terrígenous Quatemary sediments by optically stimulated luminescence (OSL) techniques. The second methodological aim consists in construct a conceptual model for the configuration and dynamics of aeolian systems, from a systemic perspective. To reach these aims, the main objectives drawn are: to define by remote sensing the spatial distribution of aeolian morphologic elements and morpho-stratigraphic unities in coastal and interior Brazilian dune fields; to make the depositional facies and stratigraphic unities analysis in selected dune fields; to date these unities by OSL and to do their textural, mineralogical and petrographic characterization; to integrate the field, laboratory and dating data set, aiming to evaluate possible relations between ages and sedimentary supply variations; to link these supply variations with changes in the fundamental control factors of the aeolian sedimentation, with special attention to the relative sea level (RSL) and to the climate. The realization of this late objective demands to know, in a secure and precise way, the variation of these control factors along the geological time. Thus, two parallel objectives are established: the critical bibliographic compilation and correlation of Quatemary paleoclimatic reconstructions in different regions of Brazil, from distinct kinds of data (palinogical, isotopic etc); and the refinement of the Holocene RSL curve, in strategic sectors of the Brazilian coast, by means of leveling and 14C dating of fossil vermetidae shells. (AU)