Environmental Changes Inferred from Environmentally Sensitive Grainsize Component Records in Chaiwopu Lake, Xinjiang

Key words: 
• Chaiwopu Lake /
• lake sediment /
• grain size /
• sensitive components
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Abstract: Grainsize analysis of a sediment core CW02 and surface sediments of the drainage area, retrieved from Chaiwopu Lake of Xinjiang, were carried out using a Malvern 2 000 grainsize analyzer.  Combining with 137Cs dating, a continuous highresolution record of environmental changes was studied over the past 150 years. Firstly, according to primary components analysis of the contents of different grainsize, the material source of lake sediment was discussed. It showed that the large particle fraction of lake sediment was from the drainage surface sediment. And then, environmentally sensitive grainsize components were extracted by the variations of the grainsize standard deviation. The results indicated that the content/meansize of sensitive grainsize component (20~209 μm) is sensitive to the regional sanddust storm events in Chaiwopu lake basin. During the last 150 years, the strong sanddust storm occurred during 1910—1930AD and 1980—2000AD. Historical documents also recorded the strong dust storms around 1910s and 1980s. Based on the analysis of the abrupt change points, the sediment grainsize increased abruptly around 1910AD, which indicated an abrupt environmental event. 