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GEOREF RECORD

Order-disorder relationships of plagioclase in a porphyritic basalt flow

Jerry M. Hoffer
Order-disorder relationships of plagioclase in a porphyritic basalt flow
American Mineralogist (June 1968) 53 (5-6): 908-916

Abstract

The structural state of phenocryst and groundmass plagioclase from a thick prophyritic flow of the Columbia River Basalt ranges from high to intermediate disorder. Two groups have been differentiated: (1) Groundmass plagioclase in a lower structural state than phenocrysts; the groundmass plagioclase is more calcic than the An (sub 50) and of small size. (2) Groundmass plagioclase in a higher structural state than phenocrysts; groundmass plagioclase generally less calcic than An (sub 50) and of large size. The latter group contains smaller amounts of glass than those of group one. The reversal in structural state relationship between the phenocryst and groundmass plagioclase of (2) is probably due to the sluggishness of the transformation from disorder to order in plagioclase less calcic than An (sub 50) .


ISSN: 0003-004X
EISSN: 1945-3027
Coden: AMMIAY
Serial Title: American Mineralogist
Serial Volume: 53
Serial Issue: 5-6
Title: Order-disorder relationships of plagioclase in a porphyritic basalt flow
Author(s): Hoffer, Jerry M.
Pages: 908-916
Published: 196806
Text Language: English
Publisher: Mineralogical Society of America, Washington, DC, United States
Accession Number: 1968-058998
Categories: Mineralogy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N42°00'00" - N49°00'00", W117°15'00" - W111°04'60"
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: 1968
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