The textural features of sandy beaches along the Apulian coast.

The Apulia Region (Southern Italy) contains about 900 km of coastal sectors, which corresponds to 12% of the Italian littorals. Most of the economic and social activities are related to the coastal areas (fishing, transports, etc.) and the tourist facilities are concentrated in the coastal localities. Among all the different coastal types, sandy beaches are the most common (more than 650 km in length) since cliffs and rocky shores only give ¼ of the littoral sectors. Therefore, the coastal erosion is one the most potential threats for the economic development of the Apulia Region. In addition, the Apulian sandy beaches show a large variability, which is characterised by different sedimentological and ecological parameters of the Ionian and Adriatic coastal areas. This variability mainly depends on both variables coastal dynamics and terrigenous/bioclastic supply. In this study, we try to describe some present-day Apulian sandy beaches by using a limited set of quantitative parameters. To purpose this aim, three different sandy beaches from Apulia coast have been chosen: Torre Canne (Brindisi) and Alimini (Lecce) on the Adriatic coast and Porto Cesareo (Lecce) along the Ionian coast. Sampling procedures were carried out through diving techniques from foreshore to lower shoreface environments (local wave base is about 6 m). The grain-size analysis allowed us to calculate the statistical parameters of sands with unimodal distribution. The beaches characterised by erosive phenomena were represented by well sorted sands with high kurtosis and negative skewness values, whereas stable beaches were related to poorly sorted sands with lower kurtosis and positive skewness values. The relationship between the main statistical parameters (mean versus kurtosis, kurtosis versus sorting, kurtosis versus skewness and mean versus skewness) was used to establish the erosive or stable-prograding tendency of the beach. The most frequently occurring size class of the statistical distribution was analysed with a binocular optical microscope to evaluate the sands composition in quantitative terms. Therefore, the classification of sands included quarts, feldspar, carbonate grains and other components (pyroxene, amphibole and opaque minerals). Within the carbonates class, the percentage of bioclasts was also evaluated. The shell fragments quantity was variable among the different beaches and a bioclasts percentage variability could be defined at different water depths. The grain-size distribution and the mineralogical compositional of the beach sands are significant data to obtain the evolutionary beach tendency and to establish quantitative textural parameters that can be used for comparative procedures in nourishment interventions.