东海内陆架泥质区沉积速率

对东海内陆架泥质区7个重力柱状样进行了210Pb活度分析测试,计算所得沉积速率为0.79~3.66 cm/a,平均值为1.97 cm/a,最高值出现在研究区最北端的CJ12-11号孔,属于东海高沉积强度区,其他6个柱状样沉积速率较低,属于次高沉积强度区。表层210Pb活度值分布与沉积物类型密切相关,可能主要受控于黏土矿物含量的高低;而表层210Pb活度值与悬浮体浓度则呈现出明显的正相关关系。另外,沉积速率与粒度参数综合分析,揭示了近百年来东海内陆架泥质区沉积作用稳定、泥质区呈向北扩张的趋势。

SEDIMENTATION RATE OF MUD AREA IN THE EAST CHINA SEA INNER CONTINENTAL SHELF

Seven gravity sediment cores were collected from muddy area of inner continental shelf of the East China Sea. Measurement of 210Pb activity was performed on all cores. The results demonstrate that the sedimentation rates were between 0.79 and 3.66 cm/a, with 1.97 cm/a on average. The highest sedimentation rate was recognized in core CJ12-11, located in the high sedimentation rate area of East China Sea. Six other cores with relative low sedimentation rates were located in the sub-higher sedimentation rate area. Distribution of 210Pb activity in surface sediments is correlated closely with the types of sediments, and probably controlled by the clay mineral, but shows a positive correlation with suspended matter concentration. Furthermore, these results reveal relative stable sedimentation processes in the muddy area during the past 100 years and the northward expansion of this muddy area.