EvoluÃÃo da Bacia ParaÃba Durante o Maastrichtiano-paleoceno - FormaÃÃes gramame e Maria Farinha, NE do Brasil / Evolution of the ParaÃba Basin During the Maastrichtiano-paleoceno - Formations gramame and Maria Flour, NE of Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

This work presents new information about the evolution of the Paraiba Basin during the Maastrichtian-Paleocene times. This period is represented by Gramame and Maria Farinha formations, carbonate units which occur in this basin. The main purpose of the present work was the improvement of the existent knowledge about these units. This research has used data from some outcrops along the whole basin, groundwater wells logs and wells logs from Projeto Fosfato performed by the ServiÃo GeolÃgico do Brasil - CPRM. The integration of existent data with the information obtained during the research allowed the composition of a more detailed data-base, which makes possible some reconsideration about the basin evolution. As a result it is possible to interpret, with more detail, the depositional conditions of the marine sequence and the basin evolution during the involved time. New concepts of interpretation of the genesis of sedimentary sequences (sequence stratigraphy) were applied. All the collected data (existent and new) were interpreted considering those modern concepts. As a consequence of this study it has been proposed the division of the ParaÃba Basin in three sub-basins (Olinda, Alhandra and Miriri). In this work it has been verified that the variation of the sedimentary filling along the sub-basins was controlled by tectonic events during the Upper Cretaceous, though, these events still do not have a conclusive dating. Indeed, in this research it has been observed that the transgression even, which stablished the marine domain over the basin, seems to came from the Potiguar Basin, and the region of the Olinda Sub-basin was the last one flooded. However, the effects of the regressive event, which began in the Upper Maastrichtian, were less active in this sub-basin and their effects were very intense in the other sub-basins to the north (Alhandra and Miriri). Some aspects, such as depositional environments and paleobathymetry were characterized. Three important biological events were distinguished: an initial colonization by the marine fauna during the transgression,a strong biotic reduction during the Upper Maastrichtian, and a recolonization during the Paleocene.

ASSUNTO(S)

paraÃba basin cretÃceo-terciÃrio estratigrafia de seqÃÃncias formaÃÃo gramame maria farinha formation cretaceous-tertiary formaÃÃo maria farinha geociencias bacia paraÃba sequence stratigraphy gramame formation

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