Palynoflora of the Araripe and Jatobá basins (Brazil) during the Early Cretaceous (late Aptian): Biostratigraphy and depositional controls

The Santana Group, Upper Aptian, records the post-rift stage of the Araripe and Jatobá basins. The palynological zones and its geological evolution is still controversial and requires review as new information becomes available. Palynological analysis play a crucial role in petroleum geology in Brazilian basins, as it allows for the reconstruction of paleoenvironmental conditions, stratigraphic correlation, and the definition of ages and potential areas for hydrocarbon exploration. This study integrates sedimentological and palynological data from drill cores in the Araripe and Jatobá basins, which consist of siliciclastic rocks intercalated with limestons e and evaporites intervals. Our analysis is used here to refine the temporal interval and depositional conditions of the late Aptian sequences of such basins. Palynological analysis resulted in the identification of 159 taxa and suggests the presence of the Sergipea variverrucata Biozone (P-270). The late Aptian is defined by their last occurrence of S. variverrucata. The presence of marine palynomorphs (e.g., Subtilisphaera sp. and foraminiferal test linings) indicates marine incursions into the basins. Based on palynological associations and sedimentary facies, the Santana Group consists of a fluvio-deltaic transitioning from a semi-enclosed lagoon and shallow marine environments deposited during the Early Aptian. Additionally, foraminiferal test linings in samples from the Crato Formation have been recorded, reinforcing marine incursions into the basins.