Sistemas dunares fósseis no litoral da região do Porto

• Autor(a) principal: Araújo, Maria da Assunção
• Data de Publicação: 1998
• Tipo de documento: Livro
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10216/23262
• topic: Dunas; Geomorfologia costeira - Espinho (Portugal); Geomorfologia costeira - Porto (Portugal)

In Oporto area subactual dunes can be find mainly in low, wind exposed areas. However, fossil dunes are not easy to find. They left some tiny remains, but the main proof of their existence is the imoortance of well rounded, dull sand arains in a solifluxive formation which covers thoroughly the littoral platform of this area. On the contrary, at the south of Espinho, one can find several fossil dune systems interstratified with lagunar deposits. The C ages of those fossil dunes goes from the würmina times till the "Little Ice Age". It is probable that the tectonicly subsiding context of this southern area has something to do with dune formation. However, we may suppose, also, that climate diferentiation from north to south may have some influence on that too. The polar front was passing near this area during würmian times so this might result in a strong contrast between the north and the south of the studied area. Dry and cold periods during the late Pleistocene and the Holocene might be a little dryer at the south, leading to important dune formation. Cold and moist phases might be more severe at the north, leading to solifluxive environments, and milder to the south, resulting in lagunar deposits.