A ÁREA NOROESTE DA BACIA DE CAMPOS, BRASIL, DO MESOCRETÁCEO AO NEOCRETÁCEO: EVOLUÇÃO PALEOAMBIENTAL E PALEOGEOGRÁFICA PELO ESTUDO DE FORAMINÍFEROS

Abstract

Foramini'c ral studies carried out in 15 exploratory wells, drilled offshore by Petro-brás in the north em portion of Campos Basin, São Tomé Low area, allowed the reconstructlcn of the regional biochronostratigraphic framework and paleogeographic evolution from "Mid" to Late Cretaceous. Correiative well sections and paleoenvironmental maps are presented, and the foUowing main concluslons are drawn: a) continous subsidence with progressive bathym etric increment controlled the depositlon in the area from the Albian to Maastrichtian; b) the deepening process was strongly increased during the Late Cretaceous with the establishment of an oceanic depositional settingj c) the "Mid" Cretaceous was characterlzed by relatively stable sedimentation in neritic environment ; d) restrictive paleoceanographic conditions (Iow oxygen content) were widespread in the Cenomanianf Early Turonian (?), with a scarce and lcw-dlversity mierofauna; e) the present conflguration of the São Tomé Low can be well recognized since the Maastrichtian, the apparent direction of its depositional trend being SW-NE.