Tectono-sedimentary analysis of rift initiation and rift climax stages of the Araripe Basin, Northeast Brazil

Abstract

This paper described the tectonic-sedimentary infilling that occurred during the rift initiation and rift climax stages of Araripe Basin. The main structures identified were, in order of importance, normal, strike-slip and reverse faults. This group of faults laterally places different lithostratigraphic units such as rift initiation and rift climax rocks. An example is the lateral contact of Missão Velho and Brejo Santo formations along normal NNE faults. The integration between geometric and kinematic analysis of these faults with the stratigraphic evolution is of great importance for an overall evolution of the geological evolution of Araripe Basin. Main field outcrops used in this work consist of exhibitions formed during the construction of the Transnordestina railway and the transposition of São Francisco River. Tectonic analysis performed for this work identified two main sets of faults: faults oriented toward NE-SW direction (older ones), and faults oriented toward NW-SE and WNW-ESE direction (younger ones). Additionally, strike-slip and reverse faults were also analyzed. The rift tectonics that affected Araripe Basin (extensional) reactivated old faults of the Pre-Cambrian basement and, in turn, provided normal NE-SW direction fault and also generated E-W and NW-SE orientation faults.