Caracterização sedimentológica de dez planícies intermareais localizadas nas baías norte e sul da Grande Florianópolis – SC, Brasil

Abstract

The particle size of clastic sediments can provide important information about mechanisms of transport, selection and deposition which are related to the dominant hydrodynamic processes. This study describes the superficial sediments of ten intertidal plains located along the North (one site) and South (nine sites) Bays in Florianópolis, SC, where the clam Anomalocardia brasiliana is artisanally exploited.  Systematic sedimentological sampling was carried out in all areas during the fall of 2008, summing up 464 samples. In the laboratory, samples were subjected to particle size analysis techniques. Sand was the predominant constituent in all banks analyzed, ranging from 70.59% in Maruim to 97.56% in Maciambú. Mean particle diameter varied from 1φ to 3φ in the study area, corresponding to medium to fine sands. Clay and silt attained higher percentages in Praia da Daniela bank, in North Bay, specially as compared to the banks located in the eastern and southern sectors of the South Bay. Such sediment distribution seems to be related to the more energetic characteristic of the South Bay as compared to the North Bay, where tidal and wind-induced currents are more gentle favouring the deposition of finer sediments.