Evolution of shallow and deep-water deposits included in the regressive drift succession of the Potiguar Basin (Brazilian Equatorial Margin) during the Late Cretaceous to Holocene

Abstract

The regressive drift succession (late Campanian–Holocene) corresponds to the last major sedimentary cycle of the Potiguar Basin and includes shallow and deep-water deposits that have potential plays similar to other hydrocarbon discoveries in the Brazilian Equatorial Margin and the African conjugate margin. This study aimed to perform a stratigraphic analysis of regressive drift succession, seeking a better understanding of its evolution and characterization of potential hydrocarbon reservoirs. Based on the interpretations of five exploratory wells and seven seismic lines, this study identified five depositional sequences. In the most proximal regions, sequences 1 and 2 exhibit a dominance of slope facies and sigmoidal/tangential-oblique seismic patterns. In contrast, sequences 3, 4, and 5 show complex sigmoid-oblique seismic patterns. In addition, these last depositional sequences display significant sedimentation of the shelf facies. Sequence 3 marks a remarkable carbonate development in the shelf, whereas a notable siliciclastic input characterizes Sequence 4. Sequence 5, in turn, has its configuration defined by extensive migration of distal deposits toward the proximal portions. Finally, in the distal regions, the five depositional sequences exhibit a preponderance of hemipelagic deposits, with the presence of gravitational flow deposits that occur mainly in the two oldest sequences (1 and 2).