Shoreline evolution during the last 7,000 years - at the Peró beach, Cabo Frio, Rio de Janeiro, Brazil

Abstract

The present work aims to evaluate the coastal dynamics along the Peró beach over the last 7,000 years, using shell-midden dating, sediment granulometric analysis, aerial photography from different ages, and field investigation to aid result interpretation and provide for clues on the adaptation of the methodology employed. Paleobeach reconstruction has been made possible by a combination of 14C age-dating and the interpretation of beach ridge disposition. Aerial photography from the years of 1959, 1976, and 2003 allow the evaluation of the present short-term coastline behavior, thus establishing the position of the paleobeach in relation to the current high-tide zone. Results indicate that the paleobeach situated in the present-day coastal plain dates from 3.373 - 3.000 cal A.P. Coastline variation in the 1959 - 1976 period consists of approximately 30m of accretion on its most significant point, while in the it eroded about 30m at the central beach sector during 1976 - 2003 period. In this context, results are considered satisfactory for the understanding of sedimentation dynamics at the Peró beach, in the city of Cabo Frio, Rio de Janeiro, Brazil.