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Clay Minerals of Montana Soils Formed on Volcanic Parent Materials
Author(s) -
Klages M. G.
Publication year - 1978
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1978.03615995004200050035x
Subject(s) - clay minerals , geology , cretaceous , soil water , volcanic rock , geochemistry , organic matter , cation exchange capacity , volcano , volcanic glass , mineralogy , volcanic ash , soil science , chemistry , paleontology , organic chemistry
Samples were taken of soils formed on volcanic materials varying in age from Cretaceous to Recent. The soil samples were analyzed for particle size distribution, pH, organic matter, cation exchange capacity, and exchangeable cations. Clays were separated and identified by X‐ray diffraction supported by chemical analysis. Clay mineralogy varied with age of the parent material. Recent ash in western Montana from sources in Washington and Oregon gave rise to amorphous clays in eight of nine samples. Soils on Quaternary volcanics near Yellowstone National Park had amorphous or poorly crystalline 2:1 clays. Clays of soils from Tertiary age volcanics were dominated by smectite. Cretaceous volcanics gave rise to mixed 2:1 clays similar to soils on Cretaceous sediments in the Northern Great Plains. Exchangeable cations in the soils varied with the dominant clay minerals.