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Particle shape; classification of thickness using slotted screens

John C. Ludwick
Particle shape; classification of thickness using slotted screens
Journal of Sedimentary Petrology (March 1971) 41 (1): 19-29


A shape classification of sand particles according to thickness is obtained by sieving a sediment sample through a nest of several screens with slotted openings, the widths of which are smaller in each subjacent screen. The sample is first sieved through a pair of round-holed screens, the openings of which are nearly the same. This produces a subsample narrowly limited in particle size. It is shown that the shape distribution in the sediment fraction obtained through use of the round-holed screens is unbiased. The distributions of particle thickness in the individual slotted screen fractions are shown to be bell-shaped, skewed depending on location relative to the modal class, and overlapping to a degree that is predictable. In using the method, slotted screen fraction weights are converted to number of particles per fraction. These particles are distributed keeping the areas trader the individual distributions proportional to the corresponding number of particles. The numbers of particles per standard class interval of particle thickness are summed over the different distributions to yield the desired distribution of relative particle thickness for the sample.

ISSN: 0022-4472
Serial Title: Journal of Sedimentary Petrology
Serial Volume: 41
Serial Issue: 1
Title: Particle shape; classification of thickness using slotted screens
Author(s): Ludwick, John C.
Pages: 19-29
Published: 197103
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
Accession Number: 1971-011067
Categories: Sedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1971
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