Aspectos geoquímicos que controlam a formação de Leques Arenosos na Bacia do Rio do Formoso-MG/Brasil

Abstract

The aim of this work is to investigate the influence of the litho-structural and geochemistry conditionings in the development of arenaceous fans in the hydrographic Basin of the Formoso River. The area of study is situated in Buritizeiro - North of Minas Gerais(MG), inserted in the Sedimentary Basin of the San Francisco (south portion of the homonym Craton). In order to accomplish this work, the following methodological procedures were used: bibliographical and cartographic review, chemical analysis of the lithotypes and water (ICP-AAS), gravimetrical separation, elaboration and analysis of digital elevation model (DEM) and analysis temporal-spatial through Landsat III Images (1980) and CBERS II (2007). The interpretation of the generated data indicates that the litho-geomorphic conditions and the digenetic aspects of the arenites of the Areado and Mata da Corda Group, respectively Inferior and Superior Cretaceous, present pre-disposition for geneses and development of arenaceous fans, evidenced for the index of mobilization of chemical elements (Iron), and for the morphologic conditions. The domain of the cretaceous lithotypes controls the local water dynamics representing the areas of recharge (aquiferous cretaceous ) responsible for the perennial of the Formoso River. Within this context there is the need of knowing the geneses and evolution of this landscape in order to create a plan of adequate control of the fragilities and natural potentialities of the area.