DYNAMIC ENVIRONMENT DIVISION AND SEDIMENT TRANSPORT TREND IN THE AREA OFF MIAODAO ISLANDS

Based on the grain size data of 107 surface sediment samples, Pejrup triangular graph and Gao-Collins grain size trend analysis are used to divide sedimentary dynamic environment and to reveal the sediments transport trend in the area off the Miaodao islands. Results show that the study area can be divided into 5 subregions (A, CIII, CIV, DIII and DIV) around the Miaodao Strait, and for each subarea, the distribution of sediemnts is basically symmetrical. There are two converging centers of sediment in the study area, the Dengzhou shoal and the central part of the Miaodao Strait. They are particularly affected by westward ebb current which leads the sediments transporting towards the Dengzhou shoal.The long-term transport trend of sediments is more pronounced by the combined action of wave and current, making it different from the strait area.