Sea-level rise and sediment budget controlling the evolution of a transgressive barrier in southern Brazil

This paper presents an evolutionary model for a coastal barrier in the southernmost coastal sector of Brazil during the Holocene. The dataset is based on 15-20 m drill cores and ground-penetrating radar (GPR) records. The model barrier evolution has two main steps. The first step is the transgression of the barrier controlled by sea-level rise during the Postglacial Marine Transgression, which ended at approximately 6-5 cal ka. Radiocarbon dating indicates that the coastal plain began to be flooded by lagoonal waters between similar to 10 and 6.7 cal ka. The second step comprises a barrier transgression controlled by a negative sediment budget of the beach system during the last 6-5 cal ka in a period of an overall slow sea-level fall of approximately 2 m. During the second step, the transgressive barrier migrated because of coastal erosion (the negative sediment budget) and the landward transference of sand by wind and lagoonal delta washout. (C) 2012 Elsevier Ltd. All rights reserved.