摘要
艾比湖为一典型的内陆干旱区封闭型湖泊 ,其沉积物粒度是反映湖面消长和水动力条件变化的很好记录。对该湖Ash孔湖相沉积粒度分维值的研究表明 :沉积物的粒度具有分形性 ,与传统的粒度参数相比较 ,分形的定量指标———分维值的变化具有明显的阶段性 ,能很好地揭示本地区环境变化的规律性。
Aiby Lake is a typical closed lake in inland of arid area. The changes of lake surface and hydrodynamic conditions are well recorded by grain size characteristic of lacustrine sediments. In this research we acquired a drilling core of lacustrine sediments named Ash, and its length is about 180cm. This drilling core is below current lake surface and near the shore. It is estimated that the sediments formed 300aBP. 90 sedimentary samples have been taken and the distance of two adjacent samples is 2cm or 1cm. Granularity of the samples is measured and the fractal dimensions are calculated in this research. Based on the characteristics of grain size dimensions, we can draw these conclusions: (1) The granularity of the sediments from the whole section is fractal, i.e. the distribution of the size of grains is statistically self similarity. The mean value of fractal dimensions is 2.3121. The curve of fractal dimension verse depth can be clearly divided into 4 parts. Every part has different change characteristics. Compared to traditional parameters of granularity, fractal dimension can better differentiate the changes of environment.(2) Fractal dimensions of sediments from this section well indicate the modern changing process of Bortala River transporting fragments to Aiby Lake. Combined with the lithology of the drilling core, the periodical changes of fractal dimension show the fundamental changing process of the river transporting ability: from strong to weak.(3) The value of fractal dimension (D) and its correlation coefficient (R) provided by fractal research to granularity of sediments present a set of new granularity index. Combined with traditional granularity parameters, the science sense of using fractal dimension in environment research is well showed by the granularity fractal research on Ash drilling core. More research should be done to understand the accurate meaning of fractal dimension changes.
出处
《干旱区地理》
CSCD
北大核心
2002年第4期336-341,共6页
Arid Land Geography
基金
国家重大基础研究发展规划项目 (G19990 43 5 0 2 )
"国家教育振兴计划"教育部青年教师奖励基金 (2 0 0 1DLXSBJBC12 )
