Aspectos hidrogeoquimicos da alteracão de silicatos na bacia amazõnica

Abstract

The hydrochemical characterization of the Amazon river and its main tributaries was used to avaluate the chemical erosin and silicate weathering study in the drainage basin. The geochemical model used was based on the stoichiometry dissolution and hydrolysis of different minerals associated with the comsumption of atmospheric/soil CO2 by the rock weathering. This study confirms the important role of the Andes in the solute riverine transports of dissolved and particulate material by the Amazon, and it shows that the silicate weathering rate and the atmospheric/soil CO2 consumed are higher in the Andes than in the rest of the Amazon Basin. The average silicate weathering rate estimated for the whole Amazon basin (14,8 m/My) and the average specific fluxes of atmospheric/soil CO2 consumed in the process (331x10 3) moles/km2.y) is comparable to other estimations made for other tropical-equatorial environments.