新疆乌伦古湖沉积物粒度特征揭示的环境信息

发布时间：2018-10-18 08:55

【摘要】：在放射性同位素210Pb、137Cs定年的基础上,通过对沉积物粒度参数的分析,探讨了近200年来乌伦古湖沉积物粒度敏感组分特征及其环境意义。研究表明,乌伦古湖WL孔沉积物以黏土和细粉砂为主,但在1970 AD前后,粒度参数发生了突变,其中16μm组分所占含量迅速升高,在约1830~1842 AD及1910 AD前后这两个时期,沉积物的粒度参数也有较显著的变化。对沉积物粒度频率分布曲线的分析表明,在对应时期内,沉积物的搬运介质或搬运动力发生了变化。基于此,首先通过粒径—标准偏差方法提取了粒度中的敏感组分C2(7~25μm),进而通过粒度敏感组分与器测气象数据的相关性分析,明确了组分C2含量的环境指示意义。结果表明,组分C2含量的大小与研究区冬、春季温度和冬季降水量大小有关,反映了积雪融水入湖的强度。在约1830~1842 AD、1910 AD前后,组分C2含量偏高,反映入湖水量较大、湖泊水位较高。而20世纪60年代到70年代,沉积物粒度参数的显著变化与流域人类活动的影响有关。
[Abstract]:Based on the dating of radioactive isotope 210PbC137Cs, the characteristics and environmental significance of granularity sensitive components of sediments in Wulungu Lake in recent 200 years were discussed through the analysis of sediment granularity parameters. The results show that the sediments of the WL pore in Ulungu Lake are mainly clay and fine silt, but the grain size parameters have mutated before and after 1970 AD, and the content of 16 渭 m components increases rapidly, about 1830 ~ 1842 AD and 1910 AD, respectively. The grain size parameters of sediments also changed significantly. The analysis of the distribution curve of sediment granularity frequency shows that the transport medium or transport power of sediment has changed during the corresponding period. Based on this, the sensitive component C2 (725 渭 m),) was extracted by the particle size standard deviation method, and the correlation analysis between the granularity sensitive component and meteorological data was carried out, and the environmental indication significance of component C2 content was clarified. The results show that the content of C _ 2 is related to the winter and spring temperature and the precipitation in winter, which reflects the intensity of the snow melt into the lake. Before and after 1830 ~ 1842 AD,1910 AD, the C _ 2 content of component C _ 2 is on the high side, which reflects the large amount of water entering the lake and the higher water level of the lake. From 1960s to 1970s, the significant change of sediment granularity parameters was related to the influence of human activities in the basin.
【作者单位】：中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室;中国科学院大学;
【基金】：国家自然科学基金项目(41671200,41271205,U1138301) 科技基础性工作专项(2014FY110400)~~
【分类号】：P343.3;P512.2

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