Geomorfologia da plataforma continental brasileira adjacente ao Delta do rio Parnaíba (PI - MA)

Abstract

The mapping of the features present on the continental shelves contributes to the proper interpretation of the oceanic environment, which can be used for scientific, political and strategic development, to support management, for preservation of submerged areas in general and for the future of the our planet. This study was carried out on the Brazilian Equatorial Margin, on the continental shelf adjacent to the Parnaiba River Delta (PI-MA) and had as its main objective the mapping of seabed features in this region through the use of hydroacustic data (singlebeam bathymetry), supported by sedimentological data, obtained from the Brazilian Navy's National Oceanographic Data Bank - BNDO. In the laboratory, the hydroacoustic data were interpolated using the kriging and minimum curvature methods, where the kriging method proved to be more efficient in viewing the features present in the area. The integration, analysis and interpretation of data resulted in four maps of the ocean substrate: bathymetric, slope, aspect, and sediment sample distribution that can be used as relevant units (e.g., inclination, orientation, curvature and terrain, among others). In this way, it was possible to identify a sedimentary cover from fine sand to coarse sand, sand with biodetritus, shells and gravel, presence of mud and quartz sand, whose relief is associated with differente submerged features, such as sandy banks, submarine valleys, as well as the presence of plateaus, associated with rocky outcrops and reef banks; additionally, lineaments and paleovalleys on the current shelf indicate the path that the Parnaíba River took in the past.