Aeolian sediment availability in coastal areas defined from sedimentary parameters. Application to a case study in Fuerteventura

Abstract

Wind characteristics and availability of airborne sediments control aeolian dynamics. Availability of sediments has been only estimated from dune dimensions. Nevertheless, this method is not valid in serir (stone dessert) and sand sheets deposits, where surface properties better than volume of materials define their sediment availability. The area chosen for this study is the Isthmus of Jandía (Fuerteventura, Canary Islands), which presents a high diversity of present day aeolian environments. Grain-size and compositional parameters from surface samples permit the design of its sedimentary cartography, which shows spatial and seasonal variations of the aeolian dynamics. Values of these parameters have been combined by statistical analyses to obtain a new parameter, lineal combination of mean size, sorting, skewness, and carbonate content, which has been named the Aeolian Sediment Availability (ASA) parameter. The ASA parameter presents several advantages over the previous mobility diagrams (mean size vs sorting), since it considers more sedimentary variables, has a continuous numerical gradient which permits the plotting of maps of the aeolian sediment availability, and has a clear physical meaning. Dynamics inferred from this parameter are satisfactory compared with local wind data, empirical transport rates and landscape unit maps of the area.