论文部分内容阅读
提供了珠江河口及河道10个沉积柱样210Pb法的CF模式（稳恒放射性通量模式）和CA模式（稳恒初始放射性模式）的年龄测定结果，并据此讨论珠江三角洲近百年来沉积环境的演化。研究结果表明，西江河道和珠江广州河道1980年以前沉积速率为0．5—1.0cm／a，1980年以后沉积速率增长加快，90年代达到4—6mc／a，沉积通量为4—6g／（Cm2·a）。河口沉积速率也呈逐年增长趋势，但一般比河道柱样小得多。深圳湾沉积通量与河口相似，为0．3—04g／（cm2·a）。80年代后沉积通量快速增长与该地区经济开发密切相关。伶仃洋西侧目前沉积通量为1g／（cm2·a）左右。珠江流域沉积速率近几十年来明显加快，致使某些柱样表层沉积物210Pbex值呈异常分布，且各层位226Ra有所差别。
Provides the results of the age-determination of the CF mode (steady-state radioactive flux mode) and the CA mode (steady-state initial radioactivity mode) of the 210 sediment-like 210Pb method in the Pearl River estuary and the river, and discusses the sedimentary environment Evolution. The results show that the deposition rate of Xijiang River and Pearl River was about 0.5-1.0cm / a before 1980, the deposition rate accelerated after 1980, reached 4-6mc / a in the 1990s and the deposition flux was 4-6g / (Cm2 · a). Estuary sedimentation rate also showed a trend of increasing year by year, but generally much smaller than the channel samples. Sediment flux in Shenzhen Bay is similar to that in estuaries and is 0.3-04g / (cm2 · a). After the 1980s, the rapid growth of sedimentary flux is closely related to the economic development in this area. Sediment flux on the west side of Lingdingyang is about 1g / (cm2 · a). The deposition rate of the Pearl River Basin has accelerated noticeably in recent decades, resulting in the abnormal distribution of 210Pbex values of some column-like surface sediments and the difference of 226Ra in each layer.