| 摘要: |
| 通过对渤海湾两根柱状沉积物中Li、Rb、Sr、Ba 以及Li/Ba 和Rb/Sr 的系统研究, 阐明了百年来沉积物中Li、Rb、Sr、Ba 的垂直变化特征, 发现了在不同年代沉积物中Li/Ba 和Rb/Sr 具有的协同变化规律, 揭示了沉积物Li/Ba 和Rb/Sr 作为近海区域性环境演变可能的指示作用。结果表明, 在0～20 cm沉积层间, Li、Rb 在A2 和A6 柱中均有随深度增加而增加的趋势, Sr 和Ba 随着深度的增加而降低; 近百年来, 渤海湾沉积物A2 和A6 柱中Li/Ba 和Rb/Sr 垂直变化表现出惊人的协同变化特征, Li/Ba 和Rb/Sr 在近河口的A2 柱中, 基本呈现随深度的增加而增加的趋势, 而在远离河口区域的A6 柱中, 其结果是0～15 cm 段(1963～2008 年), Li/Ba 和Rb/Sr 随深度的增加而增加, 15 cm 以下(1900～1963 年)则基本稳定, 在海洋过程作用下该区域沉积物Li/Ba 和Rb/Sr 变化发生在45 a 时间段内; 沉积物中Li/Ba 反映沉积物从河流进入海湾沉积过程中的变化, Rb/Sr 反映来源沉积物的化学风化历史并指示来源区的气候环境变迁过程。A2 沉积柱的20～22 cm(20 世纪30 年代)和10～12 cm(20 世纪60 年代), Li/Ba 出现极小值, 与1939 年和1963 年的海河流域大洪水相契合, 在0～12 cm 段, 两柱样Rb/Sr 随着深度的降低有明显减小的趋势, 对应20 世纪70 年代初至2008 年这一区域百年来气温升高并持续高温的时段。 |
| 关键词: Li/Ba 和Rb/Sr 环境变化指示 柱状沉积物 渤海湾 |
| DOI：10.11759/hykx20130901002 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(41306070) |
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| Geochemical covariation characteristics of Li/Ba and Rb/Sr and their environmental indication in recent hundred years of the Bohai Bay |
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| Abstract: |
| Based on the researches on Li, Rb, Sr and Ba concentrations and Li/Ba and Rb/Sr in two sediment cores of the Bohai Bay, the vertical variations of Li, Rb, Sr and Ba concentrations in recent hundred years were studied, the covariation patterns of Li/Ba and Rb/Sr were found, and the environmental change indications of Li/Ba and Rb/Sr to the coastal waters were revealed in this paper. The results suggested that the Li and Rb concentrations increased with depth during 0～20 m in core A2 and A6, whereas the Sr and Ba concentrations decreased with depth. Surprisedly, the vertical distributions of Li/Ba and Rb/Sr displayed covariation characteristic in recent one hundred years, that was, Li/Ba and Rb/Sr increased with depth in core A2 near the Haihe Estuary whereas those in core A6 off the estuary increased with depth during 0～15 cm (corresponding to 1963～2008 years) and then remained stable below 15 cm (corresponding to 1900～1963 years). In conclusion, the changes of Li/Ba and Rb/Sr affected by marine processes mainly occurred in recent 45 years. Li/Ba mainly reflected the deposition process change of riverine sediments entering the Bohai Bay; however, Rb/Sr dominantly reflected the chemical weathering history of original sediments and indicated climate change of source region. In core A2, the minimum value of Li/Ba appeared in 20～22 cm (corresponding to 1930s) and 10～20 cm (corresponding to 1960s), according with the floods of the Haihe River in the years of 1939 and 1963. Rb/Sr decreased with depth during 0～12 cm in both cores, according with the temperature increase during early-1970s to 2008. |
| Key words: Li/Ba and Rb/Sr environmental change indication core sediments the Bohai Bay |
