A deriva litorânea e suas implicações na gênese e orientação de barreiras arenosas pleistocênicas (região de Osório), Estado do Rio Grande do Sul, sul do Brasil

Abstract

The coastal region of Rio Grande do Sul consists of a long track of low and sandy dominated by the action of waves, littoral drift and other currents induced by waves as well as the wind strong action. The present study had the objective of relating and specifying the formation dynamics of an ancient beach environment located in the area of two sand mines in the two of Osório, in Rio Grande do Sul. The region is inside the north part of the Coastal Plain of Rio Grande do Sul (Planície Costeira do RS), in Barrier System III, of pleistocenic age (120 to 125 ky). This system contains foreshore and shoreface deposits covered by eolian sediments. In the region, there is a significant register of marine and non-marine biogenic sedimentar strutures that allowed to mark clearly the marine deposits. Besides the analysis of facies and sedimentary processes, paleocurrent data allow infer the beach paleoline of Barrier III in the region of Osório (RS), making a comparison with the present regime of waves, currents and winds that act in the coastal region of Rio Grande do Sul.