Two piston cores were manually collected in the Ghar El Melh lagoon. These cores are 126 cm (GEM4) and 98 cm (GEM3) in length. A very high-resolution sedimentological analysis (granulometric and geochemical) was applied to these cores. Moreover, 29 surface sediment samples were collected from present-day soil horizons from the Medejerda watershed to the littoral area (beaches and dunes) to assess the origin and all sources of the lagoon sediment arriving in the study area. In the laboratory, granulometric and geochemical analyses were performed on these surface samples. The particle sizes obtained are classified according to Folk and Ward (1957) into three categories (clay Φ <2µm, silt 2µm <Φ < 63µm and sand Φ > 63µm).