PadrÃes de distribuiÃÃo de foraminÃferos bentÃnicos na plataforma externa e talude superior das bacias de Campos e Santos, Ãrea de abrangÃncia do Estado do Rio de Janeiro

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The distribution of the assemblage and species abundance of foraminifera is conditioned to several ecological factors, related to physical, chemical and biological aspects. The distribution of the benthic foraminifera was analyzed for the Brazilian continental edge, encompassing the external platform and upper slope of the Campos Basin and Santos Basin, Rio de Janeiro. Had been collected 48 samples of sediment for quantitative analysis of benthic foraminifera, distribution of the sedimentary grain size and calcium carbonate content. The data consist of 17 samples of the surface of deep, collected with Van Veen type and six sedimentary successions collected with box core constituting 31 analyzed samples. The main objective of this work consisted of: (1) to determine and to compare the horizontal and vertical distribution of the benthic foraminÃferos of the analyzed portion of the platform and slope of the Campos Basin; e (2) to evaluate the possible relationship between the foraminifera assemblage, depth and substrate. About 42 taxa had been considered in the analysis. In the bathymetric distribution species in the surface of the sediment two limits were observed: (1) common species above 200 m of depth, such as Gyroidina sp., and Bolivina spp., Uvigerina peregrina and Bulimina spp., (2) common species below 300 m of depth, such as Amphistegina lessonii, Cibicides floridana, Discorbis bertheloti, Eponides repandus, Globocassidulina subglobosa, Lenticulina spp., and Textularia pseudotrochus. The pattern of vertical distribution was changeable as consequence to the local conditions and/or absence of environmental gradients in the sediment. Therefore, the sedimentary characteristics (sediment transport) indicated a marked influence on the distribution of the foraminifera in the area study

ASSUNTO(S)

foraminÃferos bentÃnicos bacias de campos e santos oceanografia padrÃes de distribuiÃÃo

ACESSO AO ARTIGO

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