GRAIN SIZE DISTRIBUTION PATTERN OF SURFACE SEDIMENT IN JINGHAI BAY AND DYNAMIC ENVIERONMENT DIVISION

The dynamics of the depositional environment in the Jinghai Bay is significantly affected by human activities. The survey at 57 stations reveals that the surface sediments in the Jinghai Bay consist mainly of sandy silt and silt, with a small amount of mud. Whereas the hydrodynamics becomes stronger, all the grain size parameters, such as mean grain size, sorting coefficient and skewness increase. Pejrup's triangular diagram was adopted to divide the Jinghai Bay into 4 dynamic environments in combination of the grain size probability cumulative curves. The sediment is dominated by suspended load, followed by saltation load and rolling load successively. The suspended load decreases with the intensification of hydrodynamics.