Eolução paleogeográfica quaternária da costa do estado de Sergipe e da costa sul do estado de Alagoas

Abstract

The coastal zones of the State of Sergipe and southern section of the State of Alagoas were studied using a Quaternary relative sea level variation approach. Six main events were recognized during the Quaternary evolution of these regions: Event I - Pleistocene. The Most Ancient Transgression eroded, through'the recession of a line of cliffs, the external front of the Barreiras Formation. Event II - Pleistocene. Deposition of a series of coalescing alluvial fains at the foot of the forementioned cliffs. Event III - 120,000 years B.P. The Penultimate Transgression partially eroded during its course the Pleistocene coalescing alluvial fans. Event IV - Pleistocene. A drop in sea level following the maximum of the Penultimate Transgressión allowed the construction of a coastal plain similar to that existing today. Event V - 5,100 years B.P. The Last Transgression partially eroded the Pleistocene coastal plain. The river's mouths were drowned giving way to estuaries. Locally, systems of barrier islands developed. Event VI - Holocene. The lowering of sea level that followed the maximum of the Last Transgression allowed the construction of the modern coastal plain. During the events II, IV, and VI a sand dune development took place.