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Layer Charge Evaluation of Expandable Soil Clays by an Alkylammonium Method
Author(s) -
Senkayi A. L.,
Dixon J. B.,
Hossner L. R.,
Kippenberger L. A.
Publication year - 1985
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/sssaj1985.03615995004900040052x
Subject(s) - nontronite , clay minerals , vermiculite , hectorite , aluminosilicate , imogolite , charge density , ultisol , montmorillonite , chemistry , allophane , soil water , mineralogy , illite , saponite , geology , soil science , organic chemistry , paleontology , physics , quantum mechanics , catalysis
The interlayer charge of five reference smectites (hectorite, saponite, two montmorillonites, and a nontronite) and clay samples from strongly acidic smectitic soils of Alabama, Mississippi (Ultisols), and Texas (Alfisol) were investigated by an alkylammonium method (AAM). The total layer charge of the reference smectites based on the chemical formula ranged from 0.31 to 0.50 mol(−) per O 10 (OH) 2 . The interlayer charge density by AAM linearly increased with increasing total charge. Nontronite had the highest tetrahedral charge and exhibited the highest interlayer charge density. A qualitative distinction of soil clay samples containing low charge and high charge smectite or vermiculite was based on the d ‐spacings of the complexes formed by a single alkylammonium compound. Changes in relative peak intensities indicated that the low charge smectite increases whereas the high charge smectite decreases with profile depth. The low charge smectite in these soils appears to have been mostly inherited from the underlying Tertiary and Cretaceous sediments whereas the high charge smectite appears to be a weathering product of the mica present in these sediments.