碎屑颗粒圆度的分形描述

Fractal description of roundness of clastic particles

碎屑颗粒圆度是指碎屑颗粒的原始棱角被磨圆的程度 ,用来表征碎屑沉积物的结构成熟度。目前普遍的做法是采用Powers 195 3年作的一组图 ,表示从尖棱角状至滚圆状各级圆度的特征 ,这一做法属于定性描述。本文借助分形几何学理论 ,利用盒维数法实现了计算机对颗粒维数的自动统计计算 。

It is defined that roundness of clastic particles is a degree of which are rounded in original edge angles.It is one of the important textural features and is usually used to indicate the textural maturity of clastic sediments.At present,the roundness is represented by a set of skeletons,which were designed by Powers in 1953.The skeletons show the rounded features from sharply angular to rounded particles.However,this method belongs to qualitative description.So it is necessary to determine the roundness quantitatively.In this paper,based on fractal theory and computer technology the procession of automatic statistics and calculations of particles fractal dimensions has been realized by box-counting method.The results show that the fractal dimensions can be considered as a quantitative index of describing the roundness of clastic particles.