Sepetiba : contribuição ao estudo dos níveis de erosão do Brasil

Abstract

The several erosion levels, in Sepetiba region were represented by crystalline hills as those occurring in various parts of D Federal forming an Appalachian structure where the lowest altitudes correspond to the islands.

            Some marine transgressions are intimately related to the geomorphological history of Baixada de Sepetiba leaving, until now, some outlines impressed in the natural landscape. Among them appears a fluvial-marine terrace from 5 to 7 metres of altitude. The disposition of its strati-graphical horizons, the nature of the material, the way the pebbles are rolled referred it closely to the Restinga de Marambaia (Holocene). In the Pleistocene when the Restinga da Marambaia did not exist the eustatic level was being modulated the waves went to this place with great force, rolling the material which are perfectly seen in all its whole.

            The first recent spits are responsible for the genesis of the lowland where the low courses of the rivers wandering on the plain carry away abundant sediments which penetrate in the quiet water of the Baia de Sepetiba, increasing its extension progressively.

            Studies made on the cost of Brazil by several authors (Prof Aziz Ab’Saber, Prof Francis Ruellan, Prof Alfredo José Porto Domingues, Prof Gilberto Osório de Almeida, Prof João Dias da Silveira) show others conditions treat justify epeirogenic and eustatic displacements connected to the glaciations that affected the general level of the seas.