The textural character of the littoral sediments between Sfântu Gheorghe and Gura Portiţa

Abstract. This paper is based on grain size analyses performed on 250 sediment samples collected with the Van Veen grab from water depths of 0 to 20 meters in the littoral area of the Black Sea situated between Sfântu Gheorghe village and Gura Portiţa. As a result of analyzing the distribution of the types of depth sediments, it has been noted that along the entire length of the area under study littoral sediments consisting of well-sorted sands with skewness levels ranging from –0.41 to 0.60 are to be found between 0 and 7 meters. At water depths between 7 and 20 meters there are frequent sediments consisting of clayey silt, followed by clay, poorly sorted and with skewness values ranging from 0.10 to 0.85. The percentage of sand in the composition of sediments (closely connected to the average diameter of the particles) decreases in a linear fashion with depth, suggesting a possible direction of transport of the sand particles from the littoral area out towards the open sea. By interpreting the grain size parameters it was noted that sandy sediments tended to move from North to South, East of Sakhalin Island. South of Sakhalin Island it is impossible to estimate in which direction sediment is being transported based on the sizes of the sand grains. This is due to the presence of organogenous particles resulted from shells, whose larger dimensions upset the normal distribution of textural parameters.