Abstract:

Thirty-seven surface sediments were collected from eight typical mangrove wetlands in Leizhou Peninsula and their grain-size distribution characteristics were analyzed. The results yielded the following conclusions: (1)Content of silt is the highest (52.9%), followed by sand (27.8%) and then clay (19.3%). (2)Major sediment types include sandy silt, clayey silt, sand and silty sand. Sandy silt and clayey silt are mainly distributed in the Nanshan, Gaoqiao and View-sea corridor. Sand and silty sand are mainly distributed in the Techeng Island and Qishui. (3)Average particle size is 5.7 $\phi$, and in general the grains are fine and soring is poor (sorting coefficient=1.90). The average skewness coefficient is -0.14, suggesting negative deviation. The average coefficient of kurtosis is 1.07, and the peak level is medium. (4)By using the cluster analysis method,it is found that sedimentary environment in the study area can be divided into three types, and different hydrodynamic conditions and sedimentary environmental characteristics are obvious. (5)Content of sand is negatively correlated with organic matter and salinity, but positively correlated with pH.The content of silt is positively correlated with organic matter and salinity, but negatively correlated with pH.Clay content is positively correlated with organic matter content and salinity, but negatively correlated with pH.

Key words: Leizhou Peninsula, mangrove wetland, grain size analysis, sedimentary environment