3D Paleoenvironment modelling of holocene sea level fluctuations along the lagos fluminenses region - Southeast Brazil

Abstract

Relative sea level variations (VNRM) played an important role in the formation of the coastal plains of Rio de Janeiro during the Holocene, as transgressive and regressive processes were responsible for shaping the geomorphology of the extensive coastal sedimentary basins of the Região dos Lagos area. Three-dimensional paleoenvironmental reconstitution models of VNRM are important to understand the coastal sedimentary evolution of a region, in environments consisting of coastal strands, lagoons, deltas, estuaries, swamps and barrier islands, which are common geomorphological features of the Brazilian coast. The objective is to develop a three-dimensional model of paleoenvironmental reconstruction in the coastal plain region of Cabo Frio, Rio de Janeiro. As a methodological procedure, faciological surveys and sedimentological analysis were carried out at six points in the studied area. The sedimentation environments were interpreted through satellite imagery, and due to the correlation found between sedimentological and geomorphological analyzes, the relative rise in sea level that affected the region is described in a three-dimensional paleoenvironmental reconstitution. Radiocarbon dating results available suggest ages between 6,330 to 4,800 cal years AP for the occurrence of these paleoenvironmental scenarios. This time interval corresponds to the beginning of an important marine transgression, a maximum holocene sea level and the posterior lowering of the relative sea level. The scenario presented by the three-dimensional environmental paleoreconstitution, referring to VNRM which affected the region during the Holocene, illustrates how a transgressive process affects a coastal sedimentary basin, leaving abundant geomorphological and sedimentological evidence and fossil record.