Stratigraphic revision of the Lower Cretaceous of the interior basins of Northeast Brazil.

Abstract

This paper intends to correct several misinformations in the stratigraphic framework presented for the Lower Cretaceous of the interior basins of Northeast Brazil. The Dom João stage is mostly within the Jurassic, although its uppermost part can range into the basal Cretaceous. The lithostratigraphic unit named Cariri or Mauriti (Araripe Basin) is surely “pre-Dom João stage”, and so it cannot be Cretaceous. The Dom João stage does not occur in the interior basins situated north of the Patos Lineament, and so it is absent in such basins as Iguatu, Malhada Vermelha, Lima Campos, Icó e Rio do Peixe, among others. The Sousa Formation (Rio do Peixe Basin) is Neocomian and unrelated to the Dom João stage. There is a regional hiatus between the Aratu and Alagoas stages, and consequently the interior basins do not include the Buracica and Jiquiá stages. The term Missão Velha in the Araripe Basin was inadequately related to two distinct litho-stratigraphic units: one corresponding to the Dom João stage (Missão Velha Formation s.s.) and an other one corresponding to the Alagoas stage (current Rio da Batateira Formation). The analysis of sequence stratigraphy indicates the evolution of many basins as policyclic, instead of monocyclic as have been interpreted.