Variations in the quatolnary sedimentation of the coastal embayments of the Ubatuba Region, state of São Paulo / VARIACOES TEMPORAIS NA SIDIMENTACAO QUARTENARIA DOS EMBAIAMENTOS DA REGIAO DE UBATUBA, ESTADO DE SAO PAU-LO.

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

The objective of the present work is to study the characteristics of the surface bottom sediments of Ilha Grande Bay, Rio de Janeiro state, and their correlation with the modern hydrodynamic processes, as well as with the sedimentary evolution of the southeastern brazilian coastal region, since the maximum regression of the Upper Pleistocene. Ilha Grande Bay consista a water body defined by the presence of Ilha Grande island. It can be divided into three distinct fisiographic units: the Western Portion, the Eastern Portion, and the Central Channel. In this work, a total of 153 surface bottom samples were collected, and the sediments were anal zed for: grain size, morphometry and surface texture, carbonate content, organic matter content, coarse fraction constituents, and heavy mineral assemblages. The studies allowed to identify four distinct sedimentary facies, characterized as: relict sediments of the Eastern Portion, modern sediments of the Central Channel and the confined areas, transgressive sediments of the Western Portion, and mixed sediments, resulting from the mixture of the previous facles. Finally, we propose amodel for the sedimentary evolution of the area since the maximum regressive of 18,000 years B.P. and considerate on the bottom dynamic of the bay.

ASSUNTO(S)

estratigrafia sedimentação sedimentation stratigraphy coastal region. região costeira.

ACESSO AO ARTIGO

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