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Please use this identifier to cite or link to this item: http://repositorio.ufba.br/ri/handle/ri/3209

Title: The Barreiras Group in the Northeastern coast of the State of Bahia, Brazil: depositional mechanisms and processes
Other Titles: Anais da Academia Brasileira de Ciências
Authors: Vilas Boas, Geraldo da Silva
Sampaio, Flávio José
Pereira, Antonio M. S.
Keywords: Barreiras Group;Tertiary;Cenozoic;State of Bahia
Issue Date: 2001
Abstract: The Barreiras Group is a Miocene to Lower Pleistocene continental terrigenous sedimentary deposit exhibiting a large occurrence along the Brazilian coast. In the Conde region, located in the northeastern part of the State of Bahia, the sedimentological characteristics of these sediments are indicative of a deposition as gravelly and sandy bed load in braided fluvial systems, related to alluvial fans, under an arid to semi-arid climate. The basal portion of the group is dominated by a gravelly-sandy lithofacies deposited by debris flows and pseudoplastic debris flows, with lesser occurrences of subaqueous deposits, characterizing a proximal fluvial system deposition. The upper portion is made up of gravelly-sandy sediments that include subaqueous, debris flows and pseudoplastic debris flows deposits. They suggest deposition in a more distal zone as indicated by the larger occurrence of subaqueous deposits and the presence, though rare, of downstream-accretion macroforms. Besides the climate control, deposition of the Barreiras Group was strongly influenced by the intraplate tectonism, which has been affecting the South America Platform since the Middle Miocene, when neotectonism began in Brazil.
Description: p. 417 - 427
URI: http://www.repositorio.ufba.br/ri/handle/ri/3209
ISSN: 1678-2690
Appears in Collections:Artigos Publicados em Periódicos (IGEO)

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