Parnaíba Basin

The Parnaíba Basin (Portuguese: Bacia do Parnaíba) is a large cratonic sedimentary basin located in the North and Northeast portion of Brazil. About 50% of its area is in the state of Maranhão, and the other 50% is in the states of Pará, Piauí, Tocantins, and Ceará. It is one of the largest Paleozoic basins in the South American Platform. The basin has a roughly ellipsoidal shape, occupies over 600,000 km, and is composed of ~3.4 km of mainly Paleozoic sedimentary rock that overlies localized rifts.

The basin as named after the Parnaíba River, which is approximately 1,400 kilometres (870 mi) long, and runs relatively parallel to the major axis of the basin.