PALEOCORRENTES, PALEOGEOGRAFIA E SEQÜÊNCIAS DEPOSICIONAIS DA FORMAÇÃO TATUÍ, CENTRO-LESTE DO ESTADO DE SÃO PAULO

Abstract

PALEOCURRENTS, PALEOGEOGRAPHY AND DEPOSITIONAL SEQUENCES IN THE TATUI FORMATION, BRAZIL Coarse-grained sandstones and conglomerates rich in silex clasts are conspicuous facies of the Tatuí Formation in the eastcentral São Paulo State , Brazil. They represent a progradation of coastal alluvial fan systems (Ibicatu) on a marine shelf. Paleocurrents indicate depositional dip towards the south, paleoshoreline with an approximate east-west direction and sediment provenance from the North. The upper part of the Tatuí Formation, interpreted as a highstand system tract, was covered by transgressive shales of the Taquaral Member (Irati Formation). During the transgressive phase, sediments of the Tatuí Formation were partially reworked by marine erosive processes, with development of wave ravinement surfaces and deposition of thin levels of conglomerates rich in silex grains, pebbles and bioclasts (scales, teeth and bones of fish and coprolites). The conglomerates are transgressive lags at the base of the Taquaral transgressive system tract.