Análise temporal da composição granulométrica de um estuário amazônico, Pará, Brasil

The situated estuaries are surrounding of transition between the continent and opened sea , with dynamics influenced for the fluvial forcantes, waves and tides acting directly it morphologic structure and sedimentary of these environments. In this sense, the present study aimed to analyze the composition and temporal variation of the particle size of the sediments of Furo Laura, Vigia-PA, its hydrodynamic sorting the degree of energy based on texture classes. Sediment samples were collected at four fixed points Hole Laura, at neap tides, held every two months and one year totaling (September and November 2011, January, March, May and July 2012). The particle size distribution of sediment samples were determined by laser equipment shimadzu, model SALD-2201, Laboratory of Chemical Oceanography, Federal University of Para. The values of the size fractions were imported into SYSGRAN ® Software for qualitative indication of the hydrodynamic in active sedimentation process based on the diagram Pejrup. Software was conducted in the same classification of the texture classes based on Shepard diagram. The results showed that the particle sizes of samples of sediments Furo Laura is composed predominantly by sand fractions, particularly fine sand. he hydrodynamics of the study area is classified as high to very high, with the texture attributes siltica type sand. The estuary Furo Laura proved to be a dynamic environment by hydrodynamic action with direct influence on the composition of the sediments.