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Micaceous Vermiculite, Glauconite, and Mixed‐Layered Kaolinite‐Montmorillonite Examination by Ultramicrotomy and High Resolution Electron Microscopy
Author(s) -
Lee S. Y.,
Jackson M. L.,
Brown J. L.
Publication year - 1975
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/sssaj1975.03615995003900040050x
Subject(s) - vermiculite , montmorillonite , kaolinite , mica , clay minerals , chlorite , muscovite , thin section , mineralogy , glauconite , materials science , geology , chemistry , quartz , composite material
Electron optical fringes of the layer structures of micaceous vermiculite (Colorado), glauconite (Wisconsin), and mixed‐lavered kaolinite‐montmorillonite (Mexico) were observed after separation of clay fractions, saturation with various cations, embedment in Epoxy, thin sectioning normal to the (001) planes by a diamond‐knife ultramicrotome, and high resolution, diffraction contrast electron microscopy. In the thin section of Cs‐saturated micaceous vermiculite, the electron optical fringes at 10Å may represent the basal crystallographic spacing of unweathered K mica; fringes at 11Å and 5.5Å may represent the (001) and (002) crystallographic basal orders of Cs vermiculite with the interlayers nearly closed; and fringes at 12.5Å may represent incompletely collapsed vermiculite (possibly lower layer charge and/or hydrous metal oxideinterlayered). The K‐saturated glauconite particles occur as thin crystal packets consisting of 5 to 20 layers of mica + vermiculite + montmorillonite with 10Å spacing; occasional interstratified 14Å spacings are believed to represent the Raman‐Jackson chlorite. A Mg‐saturated, mixed‐layer kaolinite‐montmorillonite from Mexico showed interleaving among the electron optical (001) fringes of kaolinite (7Å), montmorillonite (12 to 14Å), micaceous vermiculite (10Å), and regularly interstratified kaolinite‐montmorillonite (19Å). The mixing among the minerals in the Mexico sample appears to involve (i) a whole series of interstratifications along the Z axis, and (ii) mixing across planes defined by the X and Y axes, including regularly alternating, irregularly mixed, and zones of specific minerals.