Costa, M. S., Rollnic, M., Silveira, O. F. M., Miranda, A. G. O. and Santos, R. R. L. 2013. Morphological and sedimentological processes of an Amazon Estuary, Maguari River (Pará - Northern Brazil). Proceedings 12th International Coastal Symposium (Plymouth, England), Journal of Coastal Research, Special Issue No. 65, pp. 1110–1115, ISSN 0749-0208.-->
The Maguari river is an area influenced by both tide and waves with gentle declivity from downstream to upstream to provide until −42 m depth, averaging 24m in the channel and −5m in the margins and distal areas. These sectors offer hazard to navigation by exposing muddy-sandy bars. The river expresses the geological evolution of the region, having been originated by a tectonic fault oriented to NW-SE, through a filling process. Furthermore, it is characterized as importer of the sediments masking channel dimensions confirmed by the high current speeds. The river has about 65% of the substrate covered by mud, with extensive tidal flats. According to the sedimentological analysis, the environment has a high to very high hydrodynamic pattern ranging from silt to sandy-silt according to ratings. The low concentrations of clay show that the environment is highly energetic agreeing with other studies in the region. The organic matter concentration ranged from 0 to 12.5% with peak concentrations in the clay samples, being the entry to various chemical reactions.