The Brazilian north-northeast continental shelf, between 35° and 47° west, is composed of the offshore Barreirinhas, Piaui, Ceara and Potiguar basins. The total area within the 200-m bathymetric contour, excluding the shallow basement area, encompasses approximately 51,000 sq km. The sedimentary sections of these basins can be subdivided in several genetic sequences of strata, which by comparison, from older to younger, show the tectosedimentary and paleogeographic evolution of the area.

The Equatorial Atlantic rift (which probably started in Eo-Cretaceous time) had its great development in Aptian time. From the beginning of the rift opening to the end of Albian time, all the coastal basins were of the semigraben type tilted to the south. From Cenomanian to Santonian time, these basins gradually evolved into northward-opening marginal-type basins. At the end of this period, the final separation of South America and Africa took place, developing a north-south compressional stress in the fracture zones. As a result, folding, reverse faulting, transcurrent faulting, and grabens developed. From Campanian to Holocene, these coastal basins maintained their northward-open, marginal-basin characteristics.

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