Size analysis wears no clothes, or have movements come and gone?

Ehrlich, Robert

doi:10.2110/jsr.53.1

Cited by 26 publications

(8 citation statements)

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“…This is still widely employed and taught by geologists despite its fundamental dependence on the unverified assumption of log-normality. The use of these dubious graphical methods has received severe criticism (Ehrlich, 1983) and has led to dissatisfaction with the technique of particle size analysis in general. A more recent approach is to regard the proportions obtained in each size class as a multivariate observation of dimension equal to the number of size classes.…”

Section: Historical Backgroundmentioning

confidence: 99%

Statistics of Particle Size Data

1992

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SUMMARY This paper identifies various statistical problems in the measurement and analysis of particle sizes. The log‐skew‐Laplace distribution is proposed as a simple but effective model for particle sizes which can be readily extended to handle more complex situations such as mixtures and the marrying of measurements of different aspects of size. The model is compared with other contenders, the log‐normal and log‐hyperbolic distributions, in the analysis of sand grain data from the Hebrides.

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Section: Historical Backgroundmentioning

confidence: 99%

Statistics of Particle Size Data

1992

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“…The method has seldom been applied to geological examples despite demonstrations of its usefulness (e.g., Sharp & Fan 1963;Sharp 1973;Ehrlich 1983;Full et al 1983). Forrest & Clark (1989) used entropy groupings to categorise grain-size data from the New South Wales shelf by adopting Semple et al's (1972) multivariate extension to information theory.…”

Section: Introductionmentioning

confidence: 99%

Textural entropy groupings from a modern lake‐lagoon system and its ancient analogue

Woolfe¹

1995

New Zealand Journal of Geology and Geophysics

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Entropy analysis of grain-size distributions from 95 modern lake-lagoon sediment samples results in clusters which can be directly related to depositional setting. Similar entropy groupings of 60 samples obtained from the Pleistocene rock record show that the modern and ancient sedimentary settings are analogous. Additional splitting of the modern dataset results in groupings which reflect bedform-scale and element-scale features in the lake-lagoon system. Given sufficient data, it appears that this methodology could be used to discriminate small-scale sedimentary environments.

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“…However, over the past 15 years there has been significant criticism of the empirical descriptive statistics approach to particle size analysis. Misgiving culminated in Robert Ehrlich's editorial in 1983 questioning the usefulness of this approach in sedimentology (Ehrlich, 1983).…”

Section: Introductionmentioning

confidence: 99%

Discrimination between coastal subenvironments using textural characteristics

Sutherland¹,

Lee²

1994

Sedimentology

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The objective of this study was to discriminate between modern beach subenvironments based on textural characteristics obtained using the graphical (percentile) method, the moment method, and the log‐hyperbolic distribution (LHD). A total of 126 surface sedimentation units were sampled at the nodes of a 21 x 6 rectangular grid (1000 m2) on a carbonate sand beach, Oahu, Hawaii. Sampling was conducted at low energy conditions from the lower foreshore to the backshore. Non‐parametric discriminant analysis was used as an objective tool in defining distinct subenvironments. Confidence bands around the canonical variates derived from the graphic mean, sorting, skewness and kurtosis indicated four separate subenvironments (lower foreshore, mid‐foreshore, upper foreshore and backshore). Three distinct subenvironments were identified using the mean, sorting (standard deviation) and skewness measures derived by the method of moments. A similar subenvironment distinction was obtained using five statistics of the LHD (gamma, γ; nu ν; delta, δ; tau, τ; and xi, ξ). No significant difference was noted in textural characteristics between the upper foreshore and backshore zones, and these zones were grouped into one subenvironment. These results indicate that different process scenarios would be needed to explain different subenvironment partitioning based simply on the approach adopted. Discriminant analysis indicated that fewer subenvironment samples were misclassified and separation distances between subenvironments in bivariate canonical plots were greater for the standard moment measures compared with the statistics derived from fitting the computationally intensive LHD model. Examination of the mass frequency grain size distributions indicated that the LHD was generally the most appropriate model. These observations were confirmed by the hyperbolic shape triangle which indicated that the LHD rather than the more commonly used log‐normal distribution was generally optimal in describing sediments. These results support the use of the LHD statistical measures in subenvironment discrimination over the graphic‐inclusive measures.

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Size analysis wears no clothes, or have movements come and gone?

Cited by 26 publications

References 0 publications

Statistics of Particle Size Data

Statistics of Particle Size Data

Textural entropy groupings from a modern lake‐lagoon system and its ancient analogue

Discrimination between coastal subenvironments using textural characteristics

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