The
Santana Formation is a geologic
Lagerstätte (undisturbed fossil accumulation) in northeastern
Brazil's Araripe Basin where the states of
Pernambuco,
Piauí and
Ceará come together. The geological formation, named after the village of Santana do Cariri, lies at the base of the Araripe Plateau. It was discovered by
Johann Baptist von Spix in 1819. The strata were laid down during the early
Cretaceous, specifically during the early
Cenomanian, about 92 million years ago, in a shallow inland sea. At that time, the South Atlantic was opening up in a long narrow shallow sea.