Regional Stratigraphic Correlation of the Aptian in the Brazilian Equatorial Margin Basins
During the Aptian, the Brazilian Equatorial Margin basins underwent a period of tectonic quiescence as a result of a SAG phase. Associated with this stage, these basins were flooded by waters from the Central Atlantic Ocean, which established a connection between areas of similar sedimentation that were recognized, by that time, as one unique basin spreading from São Luis to Potiguar basins.
Important source rocks were deposited during this period by a transgressive marine event and are represented by sediments of the Codó Formation (in São Luis and Parnaíba basins), the Paracuru Formation (in Ceará Basin) and the Alagamar Formation (in Potiguar Basin).
Based on regional stratigraphic correlation, the SAG section can be divided into two portions. The first one is the lower portion (SAG 1), which is characterized by siliciclastic sediments deposited in fluvio-deltaic environment. The second and upper portion (SAG 2) is characterized by carbonatic, evaporitic and siliciclastic sediments deposited in evaporitic marine environment and host high hydrocarbon potential.
While the Brazilian Equatorial Margin basins were being influenced by marine environment during Aptian, the interior Araripe Basin was still being filled by continental sediments (the Rio da Batateira Formation). The marine influence (transgressive surface) towards the continent is only recognized in the Santana Formation (Aptian-Albian?), as a result of progressive eustatic rising movements.