Stratigraphic analysis of the sedimentary basins of Iguatu, Ceará

Abstract

The Brazilian Northeast presents an extensive geological history related to divergent tectonic events and formation of rift sequences responsible for the separation of South American and African continents during the Cretaceous. These events led to the formation of a series of sedimentary basins called the Northeast Brazilian Interior Basins, among which, the basins of Iguatu. The Iguatu Group covers a shallow sedimentary area of approximately 550 km2, described by a clastic sedimentation and clear structural control caused by Cariri-Potiguar Rifting and its Proterozoic shear zones system of NE­SW trending rifts. The basins shows a half­graben structure with gentle dips for NW and strong dips for SE. The division of Iguatu Group sediments it is by a homonymous basin, alongside the Malhada Vermelha, Lima Campos and Icó basins, adjacent to the Orós-Jaguaribe belt, but the evolution of sediment may be associated with the Patos lineament. The stratigraphy of the sedimentary package is complex because of both geological and structural settings of the area, with alternations of sedimentary rock types as sandstones, conglomerates, siltstones, shales and rhythmites. This main goal of this project its explanations on sedimentary evolution within the tectonic context of the region through geological and structural mapping, and stratigraphic analysis of Iguatu Group with the application of paleomagnetic dating methods of sediments. (AU)