东海内陆架泥区沉积物的环境敏感粒度组分

对东海内陆架泥质沉积区的DD2孔和悬浮体进行了陆源物质提取,应用激光粒度仪做了粒度分析,并分析了DD2孔粒度参数的垂向分布序列。通过计算粒级-标准偏差的变化获得了DD2孔沉积物中对沉积环境变化较为敏感的粒度组分,约 19和 130μm是DD2孔所属区域对沉积环境敏感的粒级,分别对应于东海沿岸流和风暴流沉积动力过程。敏感粒度组分含量随深度变化的分析表明,该孔上段的沉积作用主要受控于沿岸流,沉积环境相对稳定;而下段沉积环境变化大,是风暴流和沿岸流的混合作用沉积的结果。

A Study on Environmentally Sensitive Grain-size Population in Inner Shelf of the East China Sea

Grain-size distribution of 149 sediment samp les of Core DD2 and 3 suspended sediment samp les, pretreated by removing the organic matter and carbonate, are measured by use ofMalvern 2000. The samp ling sites are located in the inner shelf of the East China Sea. Vertical distribution of grain-size parameters of Core DD2 is studied. Standard deviations are calculated for all 149 samp les. Two peaks are observed in plot standard deviation values vs.grain-size classes, at about 19 and 130μm grain size, respectively. They are environmentally sensitive grain-size population. And about 19μm is sensitive to coastal current of the East China Sea, the other is to storm current. Each of these size classes rep resents a population of grainswith the highest variability through time. Vertical contents of sensitive grain-size population are carried out. It shows that the sedimentations of upper Core DD2 was controlled by coastal current and was in relatively stable environment. This result is supported by the comparison analysis between the modern suspended sediments and Core DD2. And lower part was controlled by combination of coastal and storm currents and was in unstable environment.