Palynological assemblage from Aptian/Albian from the Sergipe Basin: paleoenvironmental reconstruction

Abstract

Palynological analysis was carried out on 272 core samples from two wells (GTP-17-SE and GTP-24-SE) in the Sergipe basin with the aim of reconstruction the paleoenvironment of the upper Aptianmiddle Albian interval. The Paleoecological studies based on the abundance and composition of all palynomorph genera revealed four assemblages. The stratigraphic distribution of these assemblages allowed the definition of seven ecophases. The palynological assemblage reflects the paleoenvironmental history of the succession that is marked by the progressive late Aptian-middle Albian transgression into the area. The data, in particular the ecophases, confirm that the change from a brackish lagoon to open marine environment was controlled by sealevel during deposition of Muribeca Formation, and dominantly by a progressive sea-level rise during the beginning of the Riachuelo Formation deposition.