5. The Dinosaur Footprints in the Cretaceous Aeolian Deposits of Sanfranciscana Basin

The aeolian environments are often very restrictive to the preservation of fossil footprints. Dry sands and the low humidity substrate difficult the processes that allow the early cementation and prevent the destruction of the tracks by the wind erosion. Deflation of loose material from dry, uncemented sediments, transports away the clay and silt particles, and leaves only the sand and pebbles. These deposits, in the context of a hot and dry environment, show a narrow window of environmental conditions, which allow the footprints preservation. In the Early Cretaceous deserts of the central Gondwanaland existed well-adapted theropod communities to highly hot and arid climates. They are recognized, through ichnological data, as well as in the Sanfranciscana Basin, in the Paraná Basin (Botucatu Formation). In the Sanfranciscana Basin the dinosaur footprints occur in a context of humid interdune environment, in which isolated footprints and short theropod tracks were preserved.