Geoquímica dos sedimentos de manguezais do nordeste do Pará:o exemplo do estuário do rio marapanimnj

Abstract

The aim of this research is to understand the processes and extent of geochemical and mineralogical transformations in mangrove sediments, resulting from the transitions between continental and oceanic waters, in the Marapanim estuary, on the coast northeast of Para. The climate, topography, amplitude of tides and evaporation are the factors responsible for the direction and internal circulation of the waters in mangrove sediments, a fact already described in other regions under different climatic conditions. In contact with minerals rich in iron and clay-minerals, probably from sediments, laterites and oxisols of the Barreiras Formation, besides abundant organic matter, the interstitial hydrocirculations modify their chemical characteristics under different conditions of pH, Eh and salinity, giving rise to new phases through dissolution and precipitation.