Aeolian dune migration along the Ceará coast, north-eastern Brazil |
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| Authors: | Jose A Jimenez Luis P Maia Jordi Serra & Jader Morais |
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| Institution: | Laboratori d'Enginyeria Marítima, ETSECCPB, Universitat Politècnica de Catalunya, c/. Jordi Girona 1–3, Campus Nord Ed. D1, 08034 Barcelona, Spain (E-mail:;), Departmento de Geologia, Universidade Federal do Ceará, Campus do Pici, Bloco 912, Fortaleza, CE, Brazil,;Facultat de Geologia, Universitat de Barcelona, Martíi Franqués s/n, 08028 Barcelona, Spain,;Universidade Estadual do Ceará, Brazil |
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| Abstract: | Aeolian dune dimensions and migration rates are analysed along the Ceará coast, north-east Brazil. Dunes that are currently mobile along the Ceará coast are composed of barchans and sand sheets. The results show that barchans maintain an equilibrium form, which can be characterized by values of dimensionless shape parameters H/W and W/L , where H is the dune height, W is the wing-to-wing width and L is the dune length. Dunes are highly mobile, with average migration rates of 17·5 m year?1 for barchans and 10 m year?1 for sand sheets. The calculated migration rates were found to depend strongly on dune dimensions for both barchans and sand sheets, i.e. the larger the dune is, the lower the migration rate will be. This size dependence was associated with the existence of a representative common transport rate along the dune fields, which induces a different dune migration rate dependent on dune size. Finally, from the observed dune evolution, an aggregated scale aeolian sediment transport was inferred. This bulk transport rate, of the order of 90–100 m3 m?1 year?1, is only valid for a timescale of years to decades, which is the timescale used in dune evolution analysis. |
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| Keywords: | Aeolian transport barchans Brazil dune migration |
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