GRAIN SIZE CHARACTERISTICS AND INFLUENCE FACTORS OF THE TIDAL FLAT DEPOSITS AT THE TIAOZINI SANDBANK, JIANGSU PROVINCE

The Tiaozini sandbank is located in the center of the Radiative Sandy Ridges along the coast of Jiangsu province, formed in a special hydrodynamic environment with complex geomorphology. Surface sediment samples were collected from the tidal flat of the Tiaozini sandbank on May 11, 2009. Grain size parameters (i.e. mean size, sorting coefficient, skewness and kurtosis), the composition of sediment and the elevation of tidal flat along three profiles were acquired. Our results indicate that the sediment consists of sandy silt coarsening seawards. It is about 4-6Φ in mean size, and well sorted, with positive skewness and sharp kurtosis. Components of saltation dominate. The depositional features of the tidal flat deposits are mainly influenced by tidal creeks, tidal salt marshes, the erosion and deposition of the sand banks and land reclamation activities. Irregular coastlines caused by land reclamation in different periods are the main factor influencing the characteristics of the tidal flat.