论文部分内容阅读
^10Be是一种典型的长寿命宇宙成因核素,对其在自然界中的分布规律、迁移形式和赋存状态等地球化学行为特征的研究,是利用沉积物^10Be记录进行定年和环境示踪研究的理论基础.其中明确^10Be在不同沉积物中的赋存状态是研究^10Be保存性的基础,而^10Be在固相和液相介质中的分配系数Kd则主要反映了^10Be在固相和液相中的迁移能力,对研究自然界不同沉积物中^10Be的迁移性至关重要,直接影响到沉积物中^10Be环境示踪研究的有效性.本文尝试总结了大气成因^10Be在海洋、河流沉积物和土壤中的赋存状态,分析了^10Be分配系数Kd的分布范围及其主要控制因素.在此基础上以土壤中^10Be的分布特征、迁移规律及影响因素研究为参考实例,对比分析了目前已有对黄土-古土壤序列中^10Be地球化学行为研究取得的主要成果.建议未来应从地球化学机制方面进一步加强对黄土地层序列^10Be分布特征、浓度变化规律及可能影响因素的综合研究.为黄土^10Be示踪研究提供更全面的理论依据. “,”The geochemical study of ^10Be, a typical long-lived cosmogenic distribution, migration and speciation, is the theoretical basis of ^10Be dating radioactive nuclide, such as and environment tracing. To determine the chemical states of ^10Be in different sediments is the foundation of the study of ^10Be preservation, and the partition coefficient of ^10Be is essential in the study of mobility of ^10Be in different sediments, which directly affects the validity of ^10Be environmental tracing. In this article, we summarized the study of the chemical states and distribution of the cosmogenic nuclide ^10Be in marine sediments, fluvial sediments and soils. We also analyzed the main factors that affect the ^10Be partition coefficient. On the basis of the above analysis, we introduced the study of the distribution characteristics and the migration laws of ^10Be as well as the controlling factors behind those laws in soil as a concrete example. Compared with that in soil, major achievements of geochemical behavior study of ^10Be in loess-paleosol sequence were also introduced. To provide more comprehensive theoretical support for the study of loess^10Be tracing, we should improve the research in geochemistry mechanisms of ^10Be distribution characteristics, concentration variation and influencing factors in loess stratigraphic sequence in future work.