中文摘要：

2010年7月于祁连山西段老虎沟12号冰川积累区挖取了1个深度2.1 m雪坑。通过样品中δ^18O、可溶性离子、不溶性微粒的变化特点划分了雪坑季节,显示雪坑记录的时间跨度大于1 a。老虎沟12号冰川微粒数量浓度平均为925 513个·m L^-1,高于青藏高原地区大多数冰川;雪冰样品中可溶性离子与不溶性微粒质量浓度比值为6.9%。微粒的数量浓度和体积浓度在春季和夏季浓度较高,与同期冰川末端大气气溶胶具有同步性。雪冰样品中细颗粒物（1μm〈d〈2μm）数量占绝对优势，且微粒数量随着颗粒物粒径的增加呈现减少的趋势，微粒的体积分布符合众数粒径为8．22μm的Weibull函数特征，显示了近源沉积的特点。雪冰中不溶微粒同陆源离子Ca^2＋、Mg^2＋变化趋势基本一致，说明其可能主要来自于矿物粉尘源。

英文摘要：

In June 2010,a snowpack 2. 1 m in depth was dug at the Glacier No. 12 in the Laohugou Valley,and the glacier is the largest in the west Qilian Mountains in northern marginal zone of the Qinghai-Xizang Plateau. The dating of snow accumulation was determined based on the data of δ^18O,main ions and insoluble microparticles in the samples collected from the profiles in the snowpack. Result showed that the time of snow accumulation in the snowpack sampled was longer than one year. The average concentration was 925 513 particles·m L^-1,which was higher than that of most glaciers in the Qinghai-Xizang Plateau,and the ratio of soluble and insoluble microparticle concentrations in snow was 6. 9%. There was a distinct seasonal variation of microparticle concentration in spring and summer,which was consistent with the variation of atmospheric aerosols,Ca^2＋ and Mg^2＋ in snow. The proportion of fine microparticles with diameter of 1- 2 μm was dominant,and the microparticles decreased with the increase of particle size. The size-volume distribution of microparticles was simulated by Weibull model,the mode size was8. 22 μm and larger than that in the polar ice cores,and the proximal deposit was distinct. The change trend of insoluble microparticles was basically accorded with that of Ca^2＋ and Mg^2＋ of land-based sources,which revealed that the microparticles came mainly from the mineral dust sources.