Tectonic and stratigraphic evolution of southern Jacuípe Basin (Brazil) based on seismic sequence stratigraphy

Abstract

Jacuípe Basin, located at the northeastern Brazilian passive margin, has great hydrocarbon potential, but is considered a new frontier basin due to the lack of integrated studies. The present paper aims to comprehend the history of the basin based on the interpretation of several 2D seismic lines and well data. No pre-rift strata were detected. Within the rift supersequence, which overlies the crystalline basement of the São Francisco craton, four unconformity-bounded third-order sequences (labeled Rift 1 to 4) were recognized. Rift sequences 1 and 2 have scattered depocenters, reflecting the process of synthetic and antithetic fault installation and linkage. Rift sequence 3 has a widespread record throughout the basin. Rift sequence 4 records the ending of mechanical subsidence with minor faulting, and is followed by an uplift which caused the initial continental shelf to be exposed during most of the subsequent depositional events. The drift supersequence was split in two phases or stages. The first drift stage has sedimentation confined to the continental slope due to the uplift of the shelf region, whereas during the second drift stage sedimentation surpasses the border fault and the sedimentary succession overlies directly the rift supersequence. A structural fault map was built, depicting main faulting controls and trends, basin hinge line, main depocenters, the Jacuípe External High and a volcanic plug. The paper also clarified the still controversial southern geologic limit of the basin, and closes with a suggestion of an updated chronostratigraphic chart.