A NEW APPROACH TO THE GEOLOGICAL CONFIGURATION OF THE LOWER CRETACEOUS TUCANO AND JATOBÁ BASINS, NORTHEASTERN BRAZIL

Abstract

Until recently, the Lower Cretaceous Reconcavo-Tucano-Jatoba Rift was interpreted as being a system of basins connected since the beginning of rifting and filled by a fluvio-deltaic-lacustrine system which prograded from north to south. In this work, based on field observations, gravity data, new models for the evolution of continental rifts, and comparison with the East African rifts, the basins are interpreted as a series of half-grabens with disconnected depocenters, and which evolved separately. The isolation was effected by transfer faults - the Itapicuru and Vaza-Barris faults - which cut the rift in a NW-SE direction and are, principally the Vaza-Barris fault, controlled by basement anisotropy. According to this model, the majority of drilled wells were located on stable platforms, without suitable conditions to generate hydrocarbons, and thus the Tucano and Jatoba basins are not adequately explored.