不同沉积环境下沉积物的粒度分形特征的对比研究  

Comparising Study of Grain-size Fractal Dimensions Characteristics Between Several Sediments with Different Forming Environments

作　　者：陈冬梅[1] 穆桂金[1] 

机构地区：[1]中国科学院新疆生态地理研究所,乌鲁木齐830011

出　　处：《干旱区地理》2004年第1期47-51,共5页Arid Land Geography

基　　金：国家重大基础研究发展规划项目 (批准号 :G19990 43 5 0 2 )

摘　　要：通过计算主要来自干旱地区已知成因环境的 8组代表性沉积物的分维值 ,可以发现并不是所有的沉积物粒度都能获得有实际物理意义的分维值 ,如塔克拉玛干沙漠风成砂、洛川马兰黄土及塔里木河洪泛平原沉积物的分维值都小于 2 ,使其分维值失去了实际的物理意义 ,但是将分维值作为一种沉积物粒度分析参数 ,失去实际物理意义的分维值仍具有与部分传统粒度参数的相关关系 ;粒度分维具有明显的区域性特征 ,不同区域同种成因类型沉积物的分维值可能相差甚大。将分维值与传统粒度参数进行对比 :分维值 (D)与平均粒径 (Mz ,换算成 φ值 )可能存在有条件的弱相关关系 ,但并不总是前人所说的正比关系 ;分维值与标准偏差 (σ1)则明显呈正比关系。Eight groups of sedimentary samples were chosen from different sedimentary environment in arid area. After the value of fractal dimensions(D) of 494 samples were calculated, following conclusions can be given: (1) D and mean-diameter (Mz,in form of φ) do not exist inverse-ratio relationship previous study said, but D and standard deviation (σ1 ) do exist direct-ratio relationship. (2) The fractal dimension probably has regional feature, and D for sediments from the same sedimentary environment of different regions are unsuitable to compare with each other. (3) Not all fractal values of sediments have physical meaning in Euclidean 3D space. The fractal values of Manlan-Loess, flood-plain and windblown dune in Taklimakan Desert are less than 2 and so have no physical meaning. (4)The moraines of glacial facies has the maximal value of fractal dimensions in form of mean value, which is up to 2.59, then to be smaller is valley terrace, dusts, lacustrine, lacustrine-delta, flood-lain, loess, and desert dune has the minimal value, only 1.30.

关 键 词：沉积环境 沉积物 粒度分形 分维 

分 类 号：P512.2[天文地球—地质学]