一种新的粒度指标:沉积物粒度分维值及其环境意义  

A New Grain-size Index: Grain-size Fractal Dimension of Sediment and Its Environmental Significance

作　　者：柏春广[1] 王建[1] 

机构地区：[1]南京师范大学地理科学学院,南京210097

出　　处：《沉积学报》2003年第2期234-239,共6页Acta Sedimentologica Sinica

基　　金：国家教育振兴计划"教育部青年教师奖励基金 (基金号 :2 0 0 1DL XSBJBC12 );教育部重点项目 (基金号 :2 0 0 1JB0 0 170 )成果。

摘　　要：根据分形理论 ,对 10 0 0个不同类型沉积物样品的粒度分形结构及其分维值作了定量计算。结果表明 :各类型沉积物都具有良好的统计自相似性 ,并且各自有着不同的分维值。粒度分维值的大小与分选好坏密切相关。没有经过外力搬运与分选的风化破碎物质 (碎屑物 )——断层泥、冻土的粒度分维值接近于碎形体的分维值 2 .6 0左右 ;经过外力搬运但分选作用较弱的冰碛物、水石流、泥石流堆积物的粒度分维值也接近 2 .6 0 ;而经过强烈外力分选作用的河床、湖泊沉积物、潮滩及海底沉积物的分维值明显偏小。鉴于此 ,本文认为分维值可以作为沉积物类型判别的重要参数之一。On the basis of fractal theory, 1 000 sediment samples are used to calculate the grain-size fractal dimensions. The results show that statistical self-similarity of grain-size distribution exists in each kind of sediment, but the fractal dimensions are different for different kinds of sediments. For the sediments that have not been transported and sorted, such as the fragments of weathered crusts, permafrost and fault gouge, their grain-size fractal dimensions are close to that of fragments (2.60), model made by Turcotte, D.L. For the sediments that have been transported but not been sorted well, such as glacial debris and sediments of debris flow, their grain-size fractal dimensions are also close to, or a little smaller than the value of 2.60. For the sediments that have been transported and well sorted, their grain-size fractal dimensions are obviously lower than 2.60. The value of fractal dimension is proportional to the sorting coefficient. The grain-size fractal dimension is a new useful index for interpreting sedimentary environment.

关 键 词：粒度指标 沉积物 粒度分维值 分形理论 粒度分形结构 湖泊沉积物 海底沉积物 河床 潮滩 

分 类 号：P512.2[天文地球—地质学] P736.21