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Polycomponent Interstratified Phyllosilicates in Dolomite Residuum and Sandy Till of Central Wisconsin
Author(s) -
Lim C. H.,
Jackson M. L.
Publication year - 1980
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/sssaj1980.03615995004400040042x
Subject(s) - chlorite , kaolinite , clay minerals , vermiculite , mineralogy , montmorillonite , dolomite , geology , mica , chemistry , saturation (graph theory) , analytical chemistry (journal) , quartz , environmental chemistry , paleontology , mathematics , organic chemistry , combinatorics
Clay minerals of four central Wisconsin soil parent materials containing highly interstratified layer silicates were difficult to identify in conventional Mg‐glycerol X‐ray diffraction (XRD) patterns. One group was from dolomite residuum (65% clay); another from sandy till (6% clay, with only small resolved XRD peaks). The Mg‐saturated, glycerol‐solvated clays of the former gave X‐ray diffractograms with diffuse and continuous low‐angle scatter ending with a dropoff at the (001) spacing of 7Å. Potassium saturation and heating at 400°C yielded an intense, sharp 10Å peak, identifying coincidence of XRD peaks for mica + vermiculite + smectite. Shoulders extending from the sharpened 10Å peak to the 7Å peak and toward low‐angle spacings indicated the presence of chlorite. Incomplete collapse of interlayers at 550°C and the production of a 14.2Å peak following fusion in LiNO 3 at 300°C confirmed the presence of chlorite. Discrete kaolinite occurring in association with other phyllosilicates was revealed by the 11.2Å peak after Li saturation and DMSO intercalation. The X‐ray diffractograms indicated short‐range order in irregularly interstratified phyllosilicates occurring in ternary (3‐component), quaternary (4‐component), and quinary (5‐component) mixtures. The quantitative mineralogy, as assessed by K content, cation exchange capacity (CEC), selective dissolution, and thermal methods, averaged 15% mica, 10% vermiculite, 25% montmorillonite, 5% chlorite, and 30% kaolinite.