沉积学报2025，Vol.43Issue(1)：39-49,11.DOI:10.14027/j.issn.1000-0550.2022.163
Ф值表达的粒度与分选系数的单位问题
The Φ Value Expresses Granularity and the Unit Problem of the Sorting Coefficient
摘要
Abstract
[Objective]The grain-size parameter plays a vital role in characterizing the basic features of sediments,and it is a crucial reference for distinguishing sedimentary environments.For a long time,the particle size,Φ,and particle-size parameters based on the equal ratio system and negative logarithm conversion have been widely used in the field of geology and marine science,and have become the national standard.Among them,the mathematical con-notation of the sorting coefficient is closely related to the standard deviation,so whether the sorting coefficient has the same dimension as the particle size,and what units the sorting coefficient should have,have become a controversial issues.[Methods]In order to clarify this problem,this paper reviews the Udden-Wentworth equal ratio system and the origin of the Φ value,and provides modifications to the currently used calculation formulas.We discuss the evolu-tionary process of the calculation formulas used for determining particle-size parameters,such as the sorting coeffi-cient used in the graphic and the moment methods,and analyze the usage habits of the terms and units of the sorting coefficient used by Chinese scholars since 1970.[Results](1)In 1963,McManus modified the calculation formula of Φ and established it as a dimensionless parameter,making Φ a convenient index to express the particle size;however,Φ does not have the inherent property of a unit of measurement,and it cannot be used as a unit of length di-mension(i.e.,particle size).(2)Although the sorting coefficient is derived from the statistical standard deviation,it has been independently developed as an important parameter to describe the sorting of detrital sediments,which is parallel with the skewness coefficient,kurtosis coefficient,etc.It is recommended that units should not be added when Φ is used,because there are still units in the results of the existing sorting coefficient calculation formula.Therefore,the formula of the sorting coefficient is improved by referring to McManus'method of removing its dimen-sion.(3)The results of literature statistics show that most domestic scholars tend to use the term"sorting coefficient"rather than the statistical term"standard deviation",and do not use units when describing the sorting results.In all statistical kinds of literature,with the shortening of time,the proportion of literature using the term"sorting coeffi-cient"and describing the sorting results without using units has increased.(4)The current national standard GB/T 12763.8-2007 states that the unit of the sorting coefficient is Φ.We find that there is a typographical error in the de-scription of the particle size parameter calculation formula,and it is suggested that this needs to be corrected when next revising the standard.[Conclusions]In this paper,the origin and evolution of Φ and the existing commonly used sorting coefficient calculation formulas are reviewed based on various definitions,and the current situation of the usage of terms and units of the sorting coefficient in China is analyzed.Finally,on the basis of previous studies,some suggestions are put forward to modify the sorting coefficient calculation formula.The above work can provide suggestions for the revision and improvement of marine investigation norms,and provide suggestions for promoting the unification and standardization of terms.关键词
Ф/粒度参数/分选系数/GB/T 12763.8-2007Key words
Φ/grain-size parameters/sorting coefficient/GB/T 12763.8-2007分类
天文与地球科学引用本文复制引用
陈奇,唐雯雯,薛成凤,杨阳,高文华,杨建英,贾建军..Ф值表达的粒度与分选系数的单位问题[J].沉积学报,2025,43(1):39-49,11.基金项目
国家自然科学基金项目(42276050,U2240220) （42276050,U2240220）
中国地质调查局自然资源综合调查指挥中心地质调查项目(ZD20220611)[National Natural Science Foundation of China,No.42276050,U2240220 （ZD20220611）
Natural Resources Comprehensive Survey Command Center,China Geological Survey,No.ZD20220611] （）
