Algumas observações sobre o Cenozóico da região de Mossoró (Rio Grande do Norte)

Abstract

The studied area is located in the northwest of Rio Grande do Norte State, comprising the section N of town of Mossoro.​ The Cen​ozic sedimentation started after the regression of the Late Cretaceous, with deposition of continental arenitic sediments belonging to the lower unit of the Barreiras Group on an erosion surface elaborated in the Mesozoic limestones. Later, a new erosion phase took place, during which the middle unit of the Barreiras Group was deposited, correlative to the socalled Pd1-pediplanation. There seems to have worked a vertical fault system in the Apodi river valley, dislocating the blocks at W and at E to different heights. In the medium unit of the Barreiras Group a lateritic soil developed which also affected the highest rock terrace in the valley. The upper unit of the mentioned group is absent in the studied area, but its soil occurs over a great extension. There exist still three accumulation river terraces, beach rocks (sandstone reets) and beaches, correlative to the last few glacial stages. There occur also two dune sequences, a first one with reddish sands and a second one with yellowish sands