东居延海易溶盐沉积与古气候环境变化

通过对黑河尾闾东居延海湖相沉积物易溶盐类K^ 、Na^ 、Ca^2 、Mg^2 、SO4^2 、CO3^2-、HCO3^-、Cl^-八大离子含量和其他相关指标的分析，依据它们在地层中的变化特征，结合地层^14C年代测定结果，把东居延海湖泊变化划分为：隋唐湖泊面积较大时期、宋辽湖泊缩小时期、中世纪暖期湖泊扩张时期、小冰期湖泊缩小时期及20世纪湖泊干涸期等几个阶段。考虑近1500a来该流域气候变化和人类活动对湖泊的影响，得出了以下几个结论：近1500a来，东居延海湖区气候以干旱为主，湖泊逐渐萎缩；在干旱背景下存在气候波动，并与全球变化具有一致性；湖泊的盛衰演变受到气候变化和人类活动的双重影响，前期以自然变化为主，明清以来特别是清代以后，人类活动的影响加剧，成为主控因子。

Soluble Salt Sediments of East Juyan Lake and Its Indicating Palaeoclimate Environment Changes

By analyzing the distribution of the eight kinds of ions (K~( ), Na~( ), Ca~(2 ), Mg~(2 ), SO~(2-)_4, CO~(2-)_3, HCO~-_3, Cl~(-)) in soluble salt sediments of the East Juyan Lake and other related indicators, the variation features of them in strata are depicted. Based on the analyzing results and combined with the ~(14)C dating ages, the vicissitude of the East Juyan Lake could be divided into several phases, such as the Sui-Tang Dynasty larger lake area period, the Song-Liao Dynasty lake area shrank period, the Medieval-Warm-Age lake area extended period, the Little-Ice-Age lake area shrank period and the 20~(th) Century lake dried up period, etc. In general, arid climate dominantly controlled the study region in the past (1 500) years, as result the East Juyan Lake shrank gradually. On the background of arid climate there existed fluctuations between arid and humid, and the fluctuations kept pace with the global climate changes. Apart from climate change factor human activity is also an important influencing factor on lake vicissitude, and they played the dominant role alternatively during different periods; the natural factor predominated in the former times, but the anthropogenic factor became decisive since the Ming Dynasty especially the Qing Dynasty.