Data/hora: 07/06/2024 03:30:28

Provedor de dados: | 42
País: | Brazil
Título: | A reevaluation of the late quaternary sedimentation in todos os Santos Bay (BA), Brazil
Autores: | LESSA,GUILHERME C.; BITTENCOURT,ABÍLIO C.S.P.; BRICHTA,ARNO; DOMINGUEZ,JOSÉ M. L.
Data: | 2000-12-01
Ano: | 2000
Palavras-chave: | Estuary; Sediment; Stratigraphy; Holocene.
Resumo: | Todos os Santos Bay is a large (&lt;img ALIGN="BOTTOM" BORDER="0" SRC="http:/img/fbpe/aabc/v72n4/0052img1.gif" ALT="$ \approx$"&gt; 1000 km²), structurally controlled tidal bay in northeast Brazil. Three main drainage basins debouch into the bay, providing a mean freshwater discharge of 200 m³/s (prior to 1985), or less than 1% of the spring tidal discharge through the bay mouth. Based on the result of several sedimentological studies performed in the 1970's, five surface sedimentary facies were identified inside the bay, namely i) transgressive siliciclastic marine sand facies; ii) transgressive bay sand-mud facies; iii) a transgressive carbonate marine sand facies; iv) regressive bay-mud facies, and v) regressive fluvial sand facies. The spatial distribution of these facies would follow, somewhat closely, the hydrodynamic-energy distribution inside the bay. Seismic profiles along the bay bottom indicate the existence of several paleochannels, 5-10 m deep, blanketed at least by three different sedimentary units. The topmost sedimentary unit, 5-20 m thick, appears to be associated with the regressive bay-mud facies, and assuming that it was laid down within the last 5000 years, sedimentation rates for the central and northeastern part of the bay would average at 2,4 mm/y.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652000000400008
Editor: | Academia Brasileira de Ciências
Relação: | 10.1590/S0001-37652000000400008
Formato: | text/html
Fonte: | Anais da Academia Brasileira de Ciências  v.72 n.4 2000
Fonte: | info:eu-repo/semantics/openAccess