Estratigrafia da Bacia do Araripe: estado da arte, revisão crítica e resultados novos

Abstract

The Araripe Basin is a rift basin originated by the rupture of the Gondwana paleocontinent, known as the most complete sedimentary record Interior Basin in the northeastern Brazil. The manuscript presents the state of art of the stratigraphy of the Araripe Basin, focusing on its evolution over time with respect to stratigraphic sequences based on unconformity surfaces, presenting new results and also making a critical review of stratigraphic classifications proposals aiming to elaborate an integrated classification. The first stratigraphic proposals were elaborated in a very comprehensive and simplified form. Over time, more detailed studies have been carried out, corroborating for a better and more refined compartmentalization of the present sedimentary packages.The 1980s were essential for the geoscientific production inherent to the geology of the basin due to the interest in the oil potential of the Brazilian basins. Nevertheless, even today the basin keeps motivating many researches that lead to a better understanding of local and regional geology. The Araripe Basin has five major sequences: Paleozoic, represented by the Cariri formation; Early Rift, consisting of the Brejo Santo formation and the bottom of the Missão Velha formation; Rift, formed by the upper part of the Missão Velha formation and throughout the Abaiara formation; and post- Rift, separated in two sequences: post-rift I constituted by the Barbalha, Crato, Ipubi and Romualdo formations, and post-rift II, characterized by the Araripina and Exu formations. New results are incorporated into the Missão Velha and Abaiara formations, whose distinction is shown here; also, in relation to the Barbalha and Cariri formations new data were gathered. This work focuses on the feasibility of the data, on the interpretations proposed according to the stratigraphic norms and the proposition of a sequential stratigraphic classification.