厦门胡里山西侧海滩沉积物粒度特征分析

研究区海滩沉积物的粒度分析结果显示，（１）该区海滩中潮位线一带浅表层物质主要由粗砂至细砾级的颗粒组成，平均粒径为－０．１φ。粒度组成上有２－３个次组分，各组分的众数位分别平均为－１．２、０．４和２．５φ。（２）概率值累积曲线的各段呈“陡－缓－陡”的排布模式，与Ｖｉｓｈｅｒ的海滩沉积物的典型模式不同。

Analysis of grain size characteristics in beach sediment south Xiamen Island

Grain size characteristics and their variations in the sediment of studied area have been analyzed after field sampling with accuracy positioning, grain size analysis data processing by a newly developed software, and comprehensive analysis using grain slze distribution curves ,probability cumu1ative curves and grain size parameters. The result shows that, (1 ) The upper layer of the sedIment in the studied area is composed of coarse grained materials,mainly coarse sand and fine gravel, with 1he mean dlameter of - 0, 11.There are two or three components in the frequency distributive curves,with the mode of - 1. 2, 0. 4, 2. 5 respectively. (2) The probability cumulative curve has three main parts wlth the slop of steep-gentle-steep order, which is completely different from Visher's model for the beach sediment. And, the truncation points do not correspond to the trough positions in the fre quency distributive curve,especlally those between the coarse and intermediate components, showing that there exlsts a strong mixing. (3) All the characters above are closely related to the strong local c0astal dynamics. The different dynamic conditions in the different part of the studied area results in the difference of grain size characteristics between south and north of the area. And the seasonal variation of the coastal dynamics has also been reflected in the difference of the grain size characters between the surface and sub-surface sediment samples. (4) The eroded clastic mater1a1 from the land drainage system to the beach is an important factor as the material supply of thls beach area.