Surficial Sediment Distribution in a Complex Marine Setting—The Example of Coastal and Open Sea Areas of Evia Island, Central Aegean, Greece

This study examines sediment distribution patterns in the Aegean Sea, focusing on the western coast of Evia Island and the southern Evoikos and Petalioi Gulfs. A total of 200 granulometric data points were analyzed to evaluate textural characteristics, including mean grain size, sorting, and skewness. The findings reveal significant variation in mean grain size: finer sediments (ϕ = 5–8) dominate the northern Aegean near Skyros, while coarser sands (ϕ = 2–4) are prevalent in the South Evoikos and Petalioi gulfs. The coarsest materials (ϕ = 0–2) are found around Chalkis, with sorting generally poor except in those two areas. Negative skewness values in the northern part of the study area indicate a predominance of finer particles, while southern regions exhibit slightly positive skewness, suggesting a greater proportion of coarser grains. Complex net transport patterns between Evia and Skyros are influenced by north-northeast trending water currents from the northern Aegean, with fluvial influx observed in the southern Evia coastal area. Around Skyros, the interplay of water currents and prevailing north-northwest winds dictates the orientation of net transport vectors. In the Evoikos gulfs, sediment movement aligns with a general northward flow, featuring coarse sediments in the Petalioi Gulf and muddy deposits in the narrower northern segment, where minimal transport indicates stagnant conditions. Coarse-grained materials in North Evoikos are primarily influenced by strong tidal activity.