黄、渤海泥质沉积区现代沉积速率

利用α多道能谱仪对黄、渤海泥质沉积区岩芯的2 1 0 Pb放射性活度进行测定 ,并结合历史数据 ,对2 1 0 Pb放射性活度在岩芯中的垂向分布和现代沉积速率的平面分布进行了分析。研究区岩芯的2 1 0 Pb放射性活度垂向分布表现出 5种形式。从沉积速率来看 ,渤海东北部泥区、南黄海中部和东部泥区 ,以及北黄海中部泥区的沉积速率小于 0 .2cm/a ,为低速沉积区 ;黄河三角洲海域和莱州湾西部的沉积速率大于 1cm/a,为高速沉积区 ;山东半岛南部沿岸海域的沉积速率也较高 ;山东半岛成山头及苏北辐射沙脊群外缘海域的沉积速率为 0 ,属于无沉积区或侵蚀区。黄、渤海泥质沉积区现代沉积速率的分布特征的解释有待于沉积动力过程的深入分析

CONTEMPORARY DEPOSITION RATES OF FINE-GRAINED SEDIMENT IN THE BOHAI AND YELLOW SEAS

Deposition rates were determined for short cores collected from the Bohai and Yellow Seas on the basis of 210 Pb analysis.The profiles of 210 Pb distribution in the cores show five distinct patterns.Differences in the profile patterns reflect spatial and temporal variations in hydrodynamic and sedimentary conditions.Low deposition rates are found in the northeastern Bohai Sea,the central and eastern parts of the southern Yellow Sea,and northern Yellow Sea,with a deposition rate of smaller than 0.2cm/a.High deposition rates are in the vicinity of the Yellow River delta and western Laizhou Bay,with a value of greater than 1cm/a.Near the eastern end of the Shandong Peninsula and off the northern Jiangsu coast,the deposition rate is very small,indicating that these areas are eroding or in dynamic equilibrium.Further analysis of sediment dynamic processes is required for a better understanding of the distribution patterns of deposition rates over the Yellow and Bohai Seas.