Geological Evolution of Rio Grande do Sul Coastal Plain, Southern Brazil

• Published in: Journal of coastal research pp. 275 - 278
• Main Authors: Tomazelli, L.J., Dillenburg, S.R., Villwock, J.A.
• Format: Journal Article
• Language: English
• Published: Coastal Education & Research Foundation (CERF) 01-12-2006
• Subjects: Alluvial fans; Beaches; Coastal plains; Coasts; Geological facies; Geology; Sand; Sea level; Sediments; Shorelines
• ISSN: 0749-0208; 1551-5036

The geological evolution of the coastal plain of Rio Grande do Sul was controlled basically by Quaternary glacioeustatic sea-level fluctuations. Alluvial fan deposits developed along the inner part of the coastal plain were reworked during at least four major transgressive-regressive episodes, which were responsible for the construction of four barrier-lagoon depositional sequences that were preserved landward of the present coastline. Each barrier probably originated at the landward limit of a transgression and was preserved due to regression of the shoreline forced by a glacio-eustatic sea-level fall. The four barrier-lagoon systems are believed to have formed during the last 400 ka assuming a correlation with the highstands represented by the last major peaks of the oxygen isotopic record.