中文摘要：

高密度采集福建前湖湾海岸剖面133个泥沙样品做粒度分析,其频率曲线显示多种粒度分布特征,预示多种沉积环境的变化。采集研究剖面周边海滩、河口浅滩、河口、滨海沼泽和海岸沙丘等已知环境的样品作为目标样本。将目标样本沉积参数平均粒径（Mz）、标准偏差（σ）、峰态（Kg）设为判别参数,利用Excel计算海岸剖面样品与目标样本参数的距离,筛选最小距离样品,归为已知目标样本的同类。据此,分析了海岸剖面蕴含的6个沉积环境变化阶段。利用剖面底部淤泥测年14C=（328 15±170）a BP,和剖面上部泥炭测年14C=（24 130±100）a BP,了解这一变化发生的年代。自（32 815±170）a BP以来,前湖湾经历了河口浅滩-河口、沙丘-河口-滨海沼泽-海滩-沙丘等海岸环境演变过程。

英文摘要：

133 high density sediment samples were collected from Qianhu Bay coastal section to analyze their grain size which showed a variety of the frequency curves indicated the changes of sedimentary environment. Some sam ples of beach, shallow, estuary, seamarsh and dunes around the section were also collected to analyze grain size. Their parameters of mean particle size （Me） ,the standard deviation （0） ,kurtosis （Kg） were set as criterion to cal- culate the minimum distance between the section samples and the criterion samples. Samples with minimum dis- tance were classified to the similar of criterion sample so that to known their paleo-environment. We use this meth- od to analyze 133 coastal samples and known their environmental evolution from estuaries shallow, estuaries, dunes, seamarsh to beach. The silt sample under the bottom of the coastal section was dating of 14 C= （32 815 ± 170）a BP and known the ages of environmental changes of Qianhu Bay. Referring the sealevel changes in Fujian coastal dur ing that time we know it was climate and sealevel changes that cause the environmental changes in Qianhu Bay.