Geological environments of dinosaur footprints in the intracratonic basins of northeast Brazil during the Early Cretaceous opening of the South Atlantic

The intracratonic basins of northeast Brazil are part of a Cretaceous rift system developed along pre-existing structural trends in the basement during the opening of the South Atlantic Ocean. Sedimentary basins such as those of Sousa, Uiraúna-Brejo das Freiras, Araripe, Cedro, Iguatu, Malhada Vermelha, Lima Campos and Icó contain a wide variety of vertebrate and invertebrate ichnofossils, and invertebrate, vertebrate and plant fossils, including palynomorphs. Among the clastic continental sediments of these basins, dinosaur footprints are the most abundant vertebrate remains. The dinosaurian ichnofaunas all have the same stratigraphic-time-palaeogeographical context, and represent parts of a widespread megatracksite. Similarities in the lithofacies of the deposits where the footprints occur reflect the same tectonic, climatic and sedimentary processes. The environmental setting was influenced by the initial development of the equatorial Atlantic seaway, with an endemic biota living nearby in ephemeral rivers and shallow lakes in a hot climate.