渤海地区^(210)Pb、^(137)Cs同位素测年的研究现状  

Current Study of ^(210)Pb and ^(137)Cs Geochronology in the Circum-Bohai Sea Region

作　　者：王福[1] 王宏[1] 李建芬[1] 裴艳东[1] 范昌福[1] 商志文[1] 

机构地区：[1]中国地质调查局天津地质矿产研究所

出　　处：《地质论评》2006年第2期244-250,共7页Geological Review

基　　金：中国地质调查局国土资源调查项目(编号19991300013015)的成果。

摘　　要：近百年来环渤海地区的沉积作用是影响该区近现代地质环境变化的重要因素。本文收集了该区迄今公开发表的用于确定现代沉积速率的84组210Pb、137Cs柱状剖面(包括210Pb样柱52组,210Pb、137Cs样柱32组),其中海区39组,潮间带及沿海低地地区45组。环渤海地区的210Pb放射性活度的深度分布曲线主要表现为3种形式:理想指数衰变型、近等幅摆动型和海洋特殊动力事件影响型。根据由陆向海方向沉积速率的变化,可初步划分为沿岸低沉积速率带、开放潮坪高沉积速率带及海区低沉积速率区;区域性差异则表现为渤海湾开放潮坪区上部由北(蓟运河口)向南(老狼坨子)沉积速率表现为高—低—高,辽东湾从其西侧的锦州湾向东至辽河河口的开放潮坪地区,沉积速率递减,黄河三角洲地区及其附近海域属于间歇式快速沉积区,莱州湾西部为高速沉积区。As an important factor, modern accumulation rates have a signiiicant influence on tHe recent and present geo-environmental changes in the Circum-Bohai Sea （CBS） region,^210Pb and ^137Cs geo-chronological sections at 84 sites （^210Pbexc sections at 52 sites, ^210Pb and ^137Cs sections at 32 sites）, determining the modern accumulation rates in the CBS region, were collected. 39 cores are located in sea area and the others located on the coastal lowland and the intertidal flat. ^210Pb and ^137Cs sections collected show three essential vertical distribution patterns, （1） Ideal-Decaying-type, （2） Wiggling with Approximate Equivalent Amplitude, and （3） Episodic-Event-Influencing-type. Low accumulation rates of the coastal lowland, high accumulation rates of the intertidal flats and low accumulation rates in the sea areas were identified based on the existing differential accumulation rates. In a ＇high--low--high＇ pattern from the Jiyunhe Estuary in north to the Laolangtuozi upper part of the intertidal marsh in south along the western coast of the Bohai Bay, the rate decreases from the Jinzhou Bay intertidal flat to the Liaohe estuary in Liaodong Bay, and episodic high accumulation occurs the Yellow River Delta and the surrounding sea area while high accumulation rates exist in the Laizhou Bay.

关 键 词：环渤海海岸带及海区^210Pb、^137Cs现代沉积速率 

分 类 号：P597.3[天文地球—地球化学]