The endorheic – Exorheic transition and later stage of fluvial incision in a wet tropical margin setting: The Atlantic draining Paraíba do Sul River basin (Brazil)

Present-day endorheic drainage systems are rare in tropical humid regions and/or close to the coast. During late Cenozoic, under a climate, Paraíba do Sul River basin (SE Brazil) has developed along South America passive margin. This currently drains into Atlantic Ocean, but it preserves landforms that indicative of previous paleodrainage. study examines possibility this region was for most Neogene, prior establishment present-day and discusses transition from an exorheic system. Data obtained through analysis geomorphological features identified by remote-sensing techniques verified fieldwork, as well interpretation landscape evolution models elaborated Seppômen method. Five convergence areas possible paleobasins, Quaternary (or Pliocene) have been within basin. Each area is associated with Cenozoic graben separated structural highs which would formed paleodrainage divides. The mechanism endorheic-exorheic overspill, inland regressive erosion or, more probable, combination between these two processes. In fact, processes often occur concomitantly both contribute same result: expansion incision permanent channel infill. geological ancestral River, draining later strongly controlled very low sea levels during determined stage fluvial incision. No numerical dating yet proposed transition; nonetheless, published regional denudation rates suggest occurred sometime interval 21 5 Ma (Miocene Pliocene). decrease subsidence aforementioned grabens much wetter climate promoted overspill connection Atlantic.