| Summary: | The late Aptian section of the Sergipe-Alagoas Basin includes the initial marine transgressions records effectively responsible for the South Atlantic Ocean implantation by the end of the Cretaceous. Better known in its southern portion (Sergipe Sub-basin), the behavior of these transgressions is still poorly understood in the northeast portion of the basin (Alagoas Sub-basin). Based on the integrated analysis of biostratigraphic and faciological data from wells and outcrops, this study presents lithostratigraphic maps and paleogeographic reconstructions for two time intervals. They both mark the transition between essentially continental depositional sequences (K40; Early–Late Aptian) for those whose characteristics depositional systems were predominantly marine (K50; Late Aptian). Although separated by an important unconformity, called pre-neo-Alagoas, the reconstructions permitted to observe that the depositional processes were, in a way, much similar to the stratigraphic units below and above this unconformity. The differences are evidenced by the transgressive K50 behavior, which would have taken advantage of the same more subsided compartments of the K40 sequence. Coincidentally, these same compartments would again be the target of later transgressions, in the Cenomanian and between the Danian and Ypresian. A seção neo-aptiana da bacia de Sergipe-Alagoas engloba os registros geológicos iniciais das transgressões marinhas efetivamente responsáveis pela implantação do Oceano Atlântico Sul ao final do Cretáceo. Melhor conhecida na sua porção sul (sub-bacia de Sergipe), o comportamento destas transgressões é ainda pouco compreendido na porção nordeste da bacia (sub-bacia de Alagoas). Com base na análise integrada de dados bioestratigráficos e faciológicos de poços e afloramentos, este estudo apresenta mapas litoestratigráficos e reconstruções paleogeográficas para dois dos intervalos de tempo. Ambos marcam a transição entre sequências deposicionais essencialmente continentais (K40; Eo – Neo-Aptiano) para ...
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