Paolo Frongia

Geomorphology and sedimentology of Porto Pino, SW Sardinia, western Mediterranean

ABSTRACT This paper presents a detailed (1:4000) geomorphological, sedimentological and ecological map of a Mediterranean microtidal wave-dominated beach system and adjacent inner shelf. This map is an innovative cartographic product that integrates a range of processes of present and past timeframes. It is part of a larger cartography on the coastal geomorphology of Sardinia (Italy) aiming to facilitate coastal management practices and future scientific research. The study area is located in SW Sardinia (Italy), and focuses on Porto Pino beach, an important tourist destination of semi-pristine nature, facing environmental pressures common to many coastal Mediterranean settings. In this context, the main human impact on coastal dune habitats is described and a full environmental characterization of the beach system is presented.

Geomorphological processes of a Mediterranean Urbanized Beach (Sardinia, Gulf of Cagliari).

ABSTRACT In this study, we present a comprehensive map of a microtidal wave-dominated beach system based on an interdisciplinary sea–land approach and with the purpose of supporting a sustainable and successful beach management. The study area is located in a highly urbanized/industrialized coastal sector of the W side of Cagliari Gulf (S Sardinia, W Mediterranean). In the Main Map (1:15,000 scale), static and dynamic features of the beach system and adjacent inner shelf are divided into thematic sections, including geomorphological elements, bathymetry, sedimentological distribution, benthic habitat (mainly Posidonia oceanica meadow), hydrodynamics and anthropogenic features. The map constitutes an example of multidisciplinary benchmark to allow for long-term planning and management of this highly urbanized beach system. It is able to provide a substantial scientific support to policy-makers towards environmental restoration and sustainable development.

Magnetometry and ground-penetrating radar surveys applied to tracing potential collectors of mining-derived pollutants in coastal sediments (Piscinas Bay, Montevecchio mining area, SW Sardinia)

Abstract Dispersion of pollutants from mining areas can result in risks to human health. The dynamic interaction of geological processes can generate complex situations that favor enrichment in toxic elements by sedimentary and diagenetic mechanisms. In order to explore the distribution of iron-rich minerals in coastal and river sediments, a geophysical campaign was performed along the outlet of the Piscinas and Naracauli Rivers that drain two abandoned mining areas in SW Sardinia. Both rivers flow into the Mediterranean Sea, a bay where fluvial, marine, and eolian processes interact. The geophysical campaign comprised magnetometry and ground-penetrating radar surveys. Magnetic properties were controlled by means of magnetic susceptibility measurements along the beach and dune areas, through sampling of surface sediments, natural outcrops and trenches, and considering different grain size intervals. Results indicate enrichment in ferromagnetic minerals at the leeside of dunes and berms. Sedimentological interpretation is supported by means of ground-penetrating radar. Due to both sedimentary and diagenetic processes, the 100- to 300-μm fraction of fine sands exhibits high susceptibility. Implied tenors of toxic elements in the magnetite may represent a serious hazard to environmental and health security. The results inferred from magnetic anomalies support the applicability of the geophysical approach in order to locate high concentrations of iron-rich particles both at surface and below ground and the usefulness of joint evaluation of magnetic susceptibility and ground-penetrating radar in order to characterize the sedimentary and geomorphology-controlled magnetite distribution.