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Textural comparison of John Day volcanic siltstone with loess and volcanic ash

Richard V. Fisher
Textural comparison of John Day volcanic siltstone with loess and volcanic ash
Journal of Sedimentary Petrology (September 1966) 36 (3): 706-718

Abstract

Fields of correlation points were constructed by graphically correlating phi median grain sizes and sorting coefficients of sediments forming the volcanic siltstones. Comparison of the constructed fields with those of typical loess and ash formations suggests that textures of the siltstones of the middle Oligocene-lower Miocene John Day Formation in eastern Oregon are more characteristic of ash then of loess. Physical resemblance of the siltstones to massive loess deposits is due partly to the continuous homogenizing action of burrowing animals, root-wedging, and frost heaving which destroy what otherwise might be sharp contrasts in texture and in bedding structures within the John Day siltstones.


ISSN: 0022-4472
Coden: JSEPAK
Serial Title: Journal of Sedimentary Petrology
Serial Volume: 36
Serial Issue: 3
Title: Textural comparison of John Day volcanic siltstone with loess and volcanic ash
Author(s): Fisher, Richard V.
Pages: 706-718
Published: 196609
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
Accession Number: 1966-004891
Categories: Sedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N42°00'00" - N46°19'60", W124°34'60" - W116°34'60"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Update Code: 1966
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