Cenozoic uplift and erosion of structural landforms in NE Brazil

We investigate the evolution of uplifted areas in NE Brazil, which have been considered as residual landforms. The study focuses on the 130 km-long, 41 km-wide Pereiro Massif (PM). The structural control and the age of this uplift are the problems addressed in this study. We carried out topographic analysis, geomorphological and geological mapping, detailed structural analysis, and optically stimulated luminescence (OSL) dating to address these problems. The PM is bounded and cut by a system of steeply dipping normal and strike-slip faults, which control the morphology of the massif and associated sedimentary basins. The maximum uplift rate of the PM is 34 m.My− 1, as constrained by the age of flat topography capped by Miocene laterite, which represents the previous peneplain subsequently uplifted by ca. 600 m. The minimum uplift rate is 13 m.My− 1, as constrained by fission-track dating of differential crustal block movements across a nearby fault. In the Quaternary, erosion occurred mainly by fault-controlled scarp retreat under semi-arid conditions, with the formation of colluvial deposits along fault scarps and alluvial deposits in the low plains. These deposits are now dated between 46 and 0.4 ka, with a peak in sediment deposition in the Pleistocene/Holocene transition. It is concluded that the PM is a system of horsts and grabens that have been active in the Cenozoic.