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对青藏高原东北缘库木库里盆地阿牙克库木湖南缘的KM剖面沉积物进行了粒度分析,剖面粒度组成主要以细粉砂和砂粒占优势,质量分数分别为39.2%、26.9%.剖面粒度整体分选较差,频率分布曲线呈现多峰分布的特征,偏度从极负偏到正偏、峰态从窄到宽,反映了多种搬运方式存在;各粒度组分的分析结果表明研究区气候演化可以划分为5个阶段:1)22.0～21.0 ka BP气候冷干,湖泊水位低,西风较强,沙尘暴频繁;2)21.0～16.0 ka BP气候较前一阶段湿润,湖泊水位升高,西风减弱,沙尘暴减少;3)16.0～10.5 ka BP气候冷干、不稳定,波动幅度大,风力作用强,湖泊水位浅,沙尘暴增多;4)10.5～3.5 ka BP气候最为暖湿,西风减弱,湖水水位上升,湖泊水位达到剖面最高;5)3.5～2.0 ka BP湖泊水位降低,风力作用较强,气候变得干冷.末次盛冰期以来,受控于北大西洋气候的西风起主导作用,研究区气候随着西风的增强而变得冷干,湖泊水位降低,沙尘暴较为频繁,直至全新世受控于北纬65?太阳辐射强度的季风占主导作用,气候最为暖湿,沙尘暴较少,晚全新世以来随着太阳辐射的减弱,季风减弱,气候再次朝着冷干方向发展.
The grain size of the KM profile sediments in the southern edge of Almakamu Lake in the Kurokul Basin, northeastern margin of the Qinghai-Tibet Plateau, is mainly characterized by fine silt and sand grains with the mass fraction of 39.2% and 26.9% respectively. The overall particle size distribution of the section was poor, and the frequency distribution curve showed the characteristics of multi-peak distribution. The skewness ranged from very negative to positive and the kurtosis was narrow to wide, reflecting the existence of various handling modes. The analysis results The results show that the climate evolution in the study area can be divided into five stages: 1) the climate of 22.0-21.0 ka BP is cold and dry with low lake water level and strong westerly winds and frequent sandstorms; 2) the climate of 21.0-16.0 ka BP is wetter than the previous stage, 3) 16.0 ~ 10.5 ka BP The climate is cold and unstable, with large fluctuation range, strong wind force, shallow lake level and increased sandstorm; 4) The climate with the highest temperature of 10.5-3.5 ka BP is warm and wet, The westerly wind weakened, the water level of the lake rose, and the water level of the lake reached the highest level.5) After 3.5 ~ 2.0 ka BP, the lake water level decreased, the wind force was stronger and the climate became dry and cold. Since the last ice age, the westerly winds dominated by the North Atlantic climate played a leading role The study area climate with westerly Strong and cold, low lake water level and frequent sandstorms. Until the Holocene, the monsoon controlled by the intensity of 65◦N at North latitude dominates, with the warmest climate and less sandstorms. Since the Late Holocene, Weakened, the monsoon weakened, the climate once again toward the cold and dry direction.