Samples of surface bottom sediments carried out in four tidal channels of the east coast of Marajó Island were conducted in two distinct periods, August 2011, which corresponds to less rainy period and March 2012, considered the rainy season in the region. The main purpose of the survey consisted in identifying possible changes in the surface sediments in the both periods. To obtain these data, we performed the elimination of organic matter in sediments by the method that uses hydrogen peroxide and subsequently determining the dimensions of the particles that make up the samples, performed on a laser granulometer, followed by mineralogical analysis by x-ray diffraction. The results were plotted in Pejrup, Shepard diagrams and charts generated to show the spatial distribution of surface sediments and diffraction with mineralogical assembly. Significant changes were observed from one period to another, where the grain size fractions ranged hydrodynamically from finer sediments to coarse sand, with the presence of albite, goethite, jarosite kaolinite, muscovite, quartz and rutile.
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