中国边缘海柱样沉积物中239+240Pu的分布与时标价值  

The dating and distribution of 239+240Pu in the sediment cores of the marginal sea of China

作　　者：黄亚楠 潘少明[1] HUANG Ya-nan;PAN Shao-ming(The Key Laboratory of Ministry Education of Coastal and Island Development,Nanjing University,Nanjing 210023,China;Department of Nuclear Physics,the Australian National University,Canberra 2601,Australia)

机构地区：[1]南京大学海岸与海岛开发教育部重点实验室,江苏南京210023 [2]澳大利亚国立大学物理与工程学院,ACT堪培拉2601

出　　处：《中国环境科学》2020年第3期1235-1245,共11页China Environmental Science

基　　金：国家重点研发计划项目(2016YFA0600502);国家自然科学基金资助项目(41671466)。

摘　　要：根据中国边缘海已研究的77根239+240Pu柱样沉积物,分析了柱样沉积物中239+240Pu的来源、分布和时标特征.结果表明理论上给出的利用210Pb、137Cs和239+240Pu 3种核素进行定年可能出现的26种情况,与实际情况完全吻合.中国边缘海海陆交汇,柱样沉积物中不同来源的239+240Pu沉积叠加使得近岸海域(尤其是河口区)柱样沉积物中239+240Pu的峰型轮廓明显.从近岸到远海,受到沉积物来源方式、海水深度、黑潮混合、扩散效应和边界清除效应等综合因素的影响,柱样沉积物中239+240Pu的分布可能出现双峰(多峰)、单峰和无峰的情况.其中,柱样中239+240Pu呈现单峰分布时,与全球大气沉降的高峰年1963年相对应,时标价值可靠.不同海洋环境条件下210Pb、137Cs和239+240Pu定年的可靠性,应根据具体海洋沉积环境进行分析;海水中137Cs和239+240Pu核素沉积性质的差异,可能导致沉积峰不一致而影响定年的判断.According to 77 sedimentary cores of 239+240Pu in the marginal sea of China,the distribution and time-scale characteristics of 239+240Pu were analyzed,and 26possible cases of dating with 210Pb,137Cs,and 239+240Pu were given in theory,which were in good agreement with the actual situation.The overlapping of 239+240Pu sedimentary cores from different sources made the peak profile of 239+240Pu obvious in the coastal waters(especially in estuaries).From near shore to far sea,the distribution of 239+240Pu in sedimentary cores may have bimodal distribution(multi-peaks),unimodal distribution and non-peak distribution due to the influence of comprehensive factors such as 239+240Pu source,seawater depth,Kuroshio current mixing,diffusion effect and boundary clear-up effect.When 239+240Pu in the sedimentary core present a unimodal distribution,it corresponded to the peak year of global fallout in 1963,and the time scale value was reliable.The reliability of 210Pb,137Cs,and 239+240Pu dating under different marine environment conditions should be analyzed according to the specific marine sedimentary environment because of the difference of sedimentary properties of 137Cs and 239+240Pu.

关 键 词：中国边缘海 210Pb 137Cs 239+240Pu 定年 柱样沉积物 

分 类 号：X55[环境科学与工程—环境工程]