Sedimentological Sectorization of An Estuarine System In A Regressive Coast, Southeast Brazil

Multivariate statistical analysis can be applied in order to group sediments with similar characteristics and be an important tool for the interpretation of sedimentary facies for a given depositional environment. This study investigates the use of multivariate analysis to produce a sectorization of an estuarine system located along a regressive coast (Espirito Santo, southeast Brazil). Results of cluster analysis and principal component analysis were compared to qualitative sediment interpretation based on well-known sediment classifications. Multivariate analysis defined four distinct sedimentary groups for the estuarine and adjacent inner shelf system. These groups reflect distinct sedimentary facies found along the system: inner estuarine facies, outer estuarine facies, fluvial-coastal facies, and shelf facies. This sectorization is used to propose a sedimentary facies model for the system. Sedimentological variables used in the sectorization were shown to be good indicators of depositional environments, indirectly expressing the hydrodynamic energy.