ESQUEMA EVOLUTIVO DA SEDIMENTAÇÃO QUATERNÁRIA NAS FEIÇÕES DELTAICAS DOS RIOS SÃO FRANCISCO (SE/AL), JEQUITINHONHA (BA), DOCE (ES) E PARAÍBA DO SUL (RJ)

JOSÉ MARIA LANDIM DOMINGUEZ, ABÍLIO CARLOS DA SILVA PINTO BITTENCOURT, LOUIS MARTIN

Resumo


Quaternary sea level fluctuations along the east coast of Brazil played an important role on the development of the coastal plains of the São Francisco, Jequitinhonha, Doce e Paraíba do Sul rivers. The following eight stages have been recognized representing the Quaternary evolution of these features: Stage 1 - Pliocene - deposition of the Barreiras Formation as a series of alluvial fans; Stage 2 - Pleistocene - the Most Ancient Transgression; erosion during its course of the external front of the Barreiras Formation; Stage 3 - Pleistocene - deposition at the foot of the coastal cliffs, carved in the Barreiras sediments by the Most Ancient Transgression; of coalescing alluvial fans; Stage 4 - 120,000 years B.P. - the Penultimate Transgression partially eroded the Pleistocene alluvial fans; Stage 5 - Drop of sea level, leading to the construction of coastal plains similar those which exist today; Stage 6 - 5,100 years B.P. - the Last Transgression partially eroded and drowned the Pleistocene coastal plains, which became in part isolated from the open sea by barrier islands; Stage 7 - construction of intralagoonal deltas in the lagoon systems associated with the afore mentioned barrier-islands; and Stage 8 - a regression allowed the development of present day coastal plains.

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