中文摘要：

以Mastersizer2000激光粒度仪测出的粒度数据为基础，应用分形理论计算得出：七顶山马兰黄土的粒度分维值介于2．2085～2．3184之间，平均值为2．2744，相关系数为0．8835；离石黄土粒度分维值介于2．2748～2．4237之间，平均值为2．3467，相关系数为0．8920。全剖面粒度分维值在2．2085～2．4237之间，平均值为2．3187，相关系数达0．88以上，粒度分布具有分形特征（0．76μm～263．75μm的标度范围内）。分维值的大小对黄土的形成环境有良好的指示意义。本区马兰黄土比离石黄土的分维值低，说明马兰黄土沉积时东亚冬季风强盛，气候寒冷干燥，次生成壤作用弱，分选系数偏小，分选性比离石黄土稍好，自组织程度低，分维值偏低且变化幅度小；离石黄土沉积时夏季风较冬季风强盛，气候温暖湿润，后期的成壤改造作用强，分选较差，分选系数硝大，自组织程度高，分维值偏高且变化幅度大。经对比分析得出：粒度分维值反映的环境演变与磁化率、粒度所反映的环境演变一致。

英文摘要：

Using the Mastersizer2000 laser particle size analyzer to measure the particle size dates and applying of fractal theory to calculate the date. Results showed that Liao South seashore Malan Loess fractal dimension value is between 2. 2085 and 2.3184, with an average of 2. 2744, the correlation coefficient is of 0.8835 ; Lishi Loess size fractal dimension is between 2.2/48 and 2.4237, and with an average of 2.3467, the correlation coefficient is of 0. 8920. The whole profile fractal dimension value is between 2. 2085 and 2.4237, average of 2. 3187, amd the correlation coefficient is more than 0.88. Its show that the grain - size distribution has fractal characteristics. Fractal dimension of size on the formation of the Loess environment has a good index significance. The fractal dimension of Malan loess is lower than Lishi Loess, it indicates Malan loess deposited when the East Asian winter monsoon was strong, climate was cold and dry, secondary soil - forming processes was weak, sorting coefficient was too small, the sorting of the Malan loess was slightly better than Lishi loess, and was at low level of self - organization, the low value of fractal dimensional and its variation is infrequent; the summer wind was stronger when Lishi loess deposition, climate was warm and humid , the latter role of the soil was strong and poor separation, sorting coefficient was slightly larger, with a high degree of self - organization and a high value of fractal dimension. Meanwhile , its variation was frequent. After comparative analysis, it indicated that fractal dimension reflects the evolution of the environment coinside with magnetic susceptibility and grain - size.