三种碎屑颗粒形态定量分析方法的比较及应用  

Comparison and Application of Three Quantitative Methods to Describe Sedimentary Particle Shapes

作　　者：王为[1] 许刘兵[1] 刘志鹏[1] 黄日辉[1] 赖宜讯[1] 刘韫[1] 邓茹萍[1] 

机构地区：[1]华南师范大学地理科学学院,广州510631

出　　处：《地质论评》2013年第3期553-562,共10页Geological Review

基　　金：国家自然科学基金项目(编号:40871020)资助的成果

摘　　要：沉积物颗粒的形态是沉积成因分析的主要标志之一。目估对比法是沉积物颗粒圆度分析中常用的方法。目估法直观、简捷,但主观因素影响较大。本文利用计算机图像分析软件Image-ProPlus6.0获取鲍尔斯目估标准颗粒的轮廓,并用3种定量方法测量这些标准颗粒的IPP圆度、轮廓分维数和傅里叶不圆度,然后对比这些圆度的划分标准与目估标准之间的差别,最后用3种圆度测定方法同时测量广东马头山风化坑和河流壶穴中碎屑颗粒的圆度,通过测量结果的对比来评价这3种定量方法的应用效果,检验这些方法能否在实际应用中代替目估方法以区分不同成因的碎屑颗粒。分析表明:目估法的磨圆度标准不是简单地表达颗粒的圆形与否,其中包括了颗粒表面结构的差异;3种定量方法的圆度划分标准很难与目估划分标准完全一致;3种方法所表征的圆度均能区分风化作用和流水侵蚀作用形成的颗粒,因此3种定量方法均可以代替目估方法测量颗粒的圆度;在不强调颗粒表面特征的前提下,IPP圆度的测量方法比其他两种方法更加有效;颗粒形态的分析结果证明河谷壶穴中的颗粒由流水侵蚀作用而成,山顶风化坑中的颗粒由风化作用而成。The shape of sedimentary particles contains information useful to recover the ancient sedimentary processes in which the particles were transported and eroded. The traditional method to obtain the grain shape property, such as the roundness, is to describe the property by comparing the grain shape to the images of standard particles. Different quantitative methods have been developed to describe the particle shape properties in the past decades. These methods in recent years have become easier to be operated with the development of computer morphological analytical techniques. In this paper, three quantitative grain shape indexes, the IPP roundness, Fractal dimensions and Fourier not roundness, were respectively used to measure the visual standard particles suggested by Powers and then sedimentary grains obtained in the field were used to examine if the three methods can be the tools replacing the traditional visual method in actual sedimentary application. The shape of particles in Powers visual standard chart were firstly detected by the three methods using a popular computer morphological analysis software, Image Pro Plus 6.0 （IPP）, to find out if the grain classifications produced by such methods could match the Powers standard. And then the three methods were also used to measure the shape of the real particles taken respectively from the mountain top weathering pits and the stream potholes developed in a same hill, Matoushan Hill of Guangdong,to see if the particle shape indexes produced by these methods could be used to discriminate between the weathering pit grains and the stream pothole grains. The results of the analysis indicated that： （1） The Powers visual standard expresses the particle shape not only by the grain outline that is rounded or not rounded, but also by the grain surface texture; （2） the shape indexes of the three methods cannot totally match the Powers visual standard; （3） all of the three methods can distinguish the grains in a weathering pit from those in a stream

关 键 词：颗粒形态分析 目估标准颗粒 山顶风化坑 河流壶穴 

分 类 号：P512.2[天文地球—地质学]