| 新疆乌伦古湖沉积物粒度特征揭示的环境信息 |
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| 引用本文： | 周建超,吴敬禄,曾海鳌.新疆乌伦古湖沉积物粒度特征揭示的环境信息[J].沉积学报,2017,35(6):1158-1165. |
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| 作者姓名： | 周建超 吴敬禄 曾海鳌 |
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| 作者单位： | 1.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, 南京 210008; |
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| 基金项目： | 国家自然科学基金项目，科技基础性工作专项，National Natural Sci-ence Foundation of China |
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| 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>16 μm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（7~25 μm），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。
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| 关 键 词： | 湖泊沉积 粒度 敏感组分 环境意义 乌伦古湖 |
| 收稿时间： | 2016-09-22 |
Environmental Information Inferred from Environmentally Sensitive Grain-size Component Records in Wulungu Lake,Xinjiang |
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| Institution: | 1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China;2.University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Analysis of a sediment core from Wulungu Lake of Xinjiang was carried out by using environmental proxy of grain-size. Combining with 210Pb and 137Cs dating, the characteristics and environmental significance of sensitive grain-size components of Wulungu Lake sediments were studied in Wulungu Lake region. The results showed that the sediment core mainly consisted of clay and fine-silty, however, grain-size displayed a sudden shift before and after 1970 AD:the coarse particle fraction (>16μm) was significantly increased. The grain size characteristics of the sedi-ments also changed significantly during 1830-1842 AD and in about 1910 AD. The analysis of grain-size frequency distribution curves of the sediment core indicated that the transportation medium or transporting force had changed sig-nificantly during corresponding periods. Based on this result, environmentally sensitive grain-size component C2 ( 7-25μm) was extracted by the variations of the grain-size standard deviation. Based on correlation analysis between sensi-tive grain-size component and meteorological data, the environmental significance of sensitive grain-size component C2 was explicated. The results indicated that the content of sensitive grain-size component C2 was related to the regional spring and summer average temperature and winter snowfall, and reflected the intensity of the snow meltwater into the lake. The significant increase of the content of component C2 during 1830~1842 AD and in about 1910 AD thus re-flect the increased water inflow and higher lake level. The significant change of grain size characteristics of the sedi-ments during 1960s-70s was related to human activity. |
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| Keywords: | lake sediments grain size sensitive component environmental significance Wulungu Lake |
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