福建洛阳江河口湿地沉积物粒度特征及其沉积环境意义

Grain size characteristics and the significance of sedimentary environments of the sediments on Luoyangjiang Estuary wetlands,Fujian Province

沉积物粒度是反映湿地沉积环境的重要指标之一.利用Mastersizer 2000型激光粒度仪对取自福建洛阳江河口不同类型湿地的6根短柱状沉积物样品进行了粒度分析.结果显示,该地区沉积物基本为粘土质粉砂,红树林湿地内的沉积物最细,分选程度最好;互花米草湿地圈闭了大量水流带来的粗、细颗粒物质,导致平均粒径相对较大,分选相对较差.粒度参数的相关分析结果显示,平均粒径与分选系数的显著正线性相关,揭示了该地区水动力作用弱、物质来源单一的沉积环境,显著增加了河口湿地沉积速率.

Sediment grain-size is an important parameter for indication of sedimentary environment. Six short cores were obtained in different types of wetlands in Luoyangjiang Estuary of Fujian Province, and the sediments were analyzed using Master sizer 2000 laser particle analyzer. The analysis shows that the sediments is dominated by clayey-silt. Sediments in mangrove wetland is the finest and the best sorted ; in Spartina alterniflora wetland, the sediments is coarser and worse sorted because the cord-grass had reduced the current flow and trapped both coarse and fine materials. Regression analysis between mean grain-size and sort coefficient shows that there is an obvious positive linear relationship. It indicates that the weak hydrodynamics and simple resources of sediments have remarkably enhanced the accumulation rate in estuarine wetlands.