A textural-based sectorization of the sandy beaches of Santa Catarina Island, SC, Brazil

Resumo

A coleta de 192 amostras de sedimentos em praias arenosas da ilha de Santa Catarina (ISC) e as análises laboratoriais subsequentes possibilitaram identificar as principais características granulométricas das praias da ilha. Conforme o critério prévio de distinção de setores pôde-se caracterizar que: a costa Noroeste, voltada para a baía Norte, apresentam textura predominante areia grossa, moderadamente selecionada, aproximadamente simétrica e mesocúrtica; na costa Norte, as praias nas enseadas de Jurerê, Canasvieiras e Ingleses apresentam textura dominante areia fina, bem selecionada, aproximadamente simétrica e mesocúrtica; na costa Nordeste, as praias voltadas para o oceano apresentam textura predominante areia média, bem selecionada, aproximadamente simétrica e mesocúrtica; na costa Sudeste, as praias voltadas para o oceano apresentam textura predominante areia média, moderadamente selecionada, assimetria negativa e mesocúrtica; na costa Sul, as praias da enseada do Pântano do Sul apresentam textura predominante areia fina, bem selecionada, aproximadamente simétrica e mesocúrtica e a costa Sudoeste, voltada para baía Sul, apresenta textura predominante areia grossa, moderadamente selecionada, aproximadamente simétrica e mesocúrtica. Puderam-se agrupar estas praias em quatro domínios distintos: domínio Oriental, de alta energia de onda, abrangendo as costas Nordeste e Sudeste; domínio Ocidental, compreendendo praias protegidas das costas Noroeste e Sudoeste; domínios Setentrional e Meridional abrangendo praias das costas Norte e Sul, semi-expostas da energia das ondas, situadas no entorno das enseadas de Canasvieiras/Jurerê e Pântano do Sul, respectivamente. As características granulométricas das praias da ISC são condicionadas principalmente pelos agentes hidrodinâmicos associados ao tipo de praia e à proximidade da área fonte.

A B S T R A C T

The collection of 192 sediment samples in the sandy beaches of the Santa Catarina island (SCI) and subsequent laboratory analyses allowed to identify the main granulometric characteristics of the island's beach.  According precedent criterion of distinction on sectors, the coasts were characterized as: in the Northwest coast, oriented to the North bay, present dominant texture of coarse sand, moderately sorted, approximately symmetric and mesokurtic; in the North coast, the beaches within Jurerê, Canasvieiras and Ingleses bays, present predominantly fine sand, well sorted, approximately symmetric and mesokurtic; in the Northeast coast, the beaches oriented to Atlantic ocean, present dominant texture of medium sand, well sorted, approximately symmetric and mesokurtic; in the Southeast coast, the beaches oriented to the ocean present dominant texture of medium sand, moderately sorted, negative asymmetry and mesokurtic; in the South coast, the beaches within the Pântano do Sul bay present dominant texture of fine sand, well sorted, approximately symmetric and mesokurtic; the Southwest coast, oriented to the South bay, present dominant texture of coarse sand, moderately sorted, approximately symmetric and mesokurtic. The beaches were arranged in four distinctive domains: Eastern domain, of high wave energy, alloying of Northeast and Southeast coasts; Western domain, comprehending protected beaches of the Northwest and Southwest coasts; Northern and Southern domain comprehending semi-protected beaches of the North and South coasts, located around Canasvieiras/Jurerê and Pântano do Sul bay, respectively. The granulometric characteristics of the SCI beaches are conditioned mainly by hydrodynamic agents associated with beach patterns and proximity of the source area.

Keywords: sediment; textural facies; hidrodynamics.