| 摘要: |
| 通过对东海近岸泥质区ZC13 和ZA3 柱状沉积物的210Pb 同位素测年和粒度分析, 分别得到了两柱状沉积物的沉积速率以及粒度特征。结果显示: ZC13 和ZA3 柱状沉积物低端对应的沉积年代分别为55 a(1955～2009 年)和140 a(1871～2010 年), 平均沉积速率为0.89 cm/a 和0.82 cm/a。ZC13 柱状沉积物以砂质粉砂为主; ZA3 柱状沉积物由顶部至100 cm 粒度组分及相关参数变化稳定, 岩性上表现为较细的黏土质粉砂, 显示较为稳定的沉积环境; 100 cm 以下岩性总体上表现为较粗的粉砂质砂, 粒度参数变化较大, 表明沉积环境受到一定的扰动。研究认为, 粒度随年代的变化受沉积物来源及沉积动力的影响。这些研究结果为研究东海近岸海域环境演变提供了研究依据。 |
| 关键词: 东海近岸泥质区 沉积速率 粒度特征 环境演变 |
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| 基金项目:国家重大基础研究规划973 项目(2010CB428706); 国家基金委创新研究群体科学基金资助项目(41121064) |
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| Variations of sediment grain size of the coastal mud area of the East China Sea and the influence factors during recent hundred years |
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| Abstract: |
| Two cores taken at station ZC13 and ZA3 from coastal mud area of the East China Sea were analysis for 210Pb dating and grain size. Results showed that the mean sedimentation rate was 0.89 cm/a during the period of 1955～2009 for the core ZC13 and 0.82 cm/a during the period of 1871～2010 for the core ZA3, respectively. The sediments of the core ZC13 were mainly composed of sandy silt. The indices of grain size parameters from top to 100 cm of the core ZA3 were relative steady and the lithology of this part was composed of clayey silty, suggesting a stable sedimentary environment. The indices of grain size parameters from 100 to 115 cm of the core ZA3 were fluctuated dramtically, suggesting a turbulent sedimentary environment and the lithology of this part was composed of silty sand. The results showed that the variations of grain size of the two cores with changes of ages were resulted from impacts of source of sediments and sediment dynamic conditions. These results have provided evidence for investigation of environmental evolutions in coastal areas of the East China Sea. |
| Key words: the mud area in East China Sea coast sedimentation rate grain size parameters environmental changes |
