Early to Middle Devonian ironstone and phosphorite in the northwestern Gondwana Parnaíba Basin, Brazil: A record of an epeiric margin paleoceanographic changes

Pragian to Givetian successions in the Canindé group, Parnaíba Basin (Brazil), present phosphorites, ironstone and organic rich sediments that globally coincide with greenhouse conditions and an increase in continental weathering, ocean oxygen levels and black shale deposition events. These facies are associated with the evolution of the northern Gondwana epeiric sea margin of the Rheic Ocean and can tell us how ocean chemistry changed and the...