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| Format: | Artículo científico |
| Language: | en |
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Academia Brasileira de Ciências
2000
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| Online Access: | https://www.redalyc.org/articulo.oa?id=32772408 |
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Table of Contents:
- A Reevaluation of the late quaternary sedimentation in Todos os Santos Bay (BA), Brazil José M.L. Dominguez Guilherme C. Lessa Abílio Bittencourt C.S.P. Arno Brichta Multidisciplinaria (Ciencias Naturales y Exactas) estuary sediment Holocene stratigraphy Todos os Santos Bay is a large ( 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. 2000 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32772408 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.4 Vol.72