Kaolinitic, montmorillonitic, illitic, and mixed-layer clay minerals are found in mud springs and mud pots of Yellowstone Park. A sequence of alteration is proposed as Phase I, alteration of bedrock and sediments by hot spring waters to produce three-layer clay minerals (including mixed layer species) and kaolinite-group minerals; Phase II, further alteration to produce a mud composed predominantly of kaolinite and some form of silica.

Aerogels of clays can be prepared by freeze-drying of clay water gels. The mechanical strength of the aerogels is improved by the addition of water-soluble polyelectrolytes to the hydrogels.

The porosity of the powdered aerogels can be adapted to the requirements for adsorbents in gas chromatography by compounding the hydrogels with suitable amounts of polyelectrolytes. Simultaneously, the surface of the clay may be modified by adsorption of polar or cationic organic compounds in order to achieve specific chromatographic separations.

Because of the toughness of the clay-polyelectrolyte aerogels, they can be rolled out to thin sheets which may be applied as chromatographic papers.

Discussions and recommendations of The Clay Mineral Society, Nomenclature Committee, 1965-6, are summarized.

Use of a platy internal standard that will orient to the same degree as clay minerals preserves the relative diffraction intensities between the basal reflections from the platy components, regardless of degree of orientation. The method is illustrated with basic zinc chloride and pyrophyllite as the internal standards for quantitative clay mineral analysis in the systems kaolinite-1Md illite and 2M1 muscovite-montmorillonite. Ulite does not orient to the same degree as kaolinite at high illite concentrations. In such nonlinear systems empirical working curves are more reliable than fixed ratios of the scattering powers of the clay minerals present. Random interstratification of 10/15.4Å layers causes a minimum in 001/001 peak height at about 33% of the 15.4Å component. Peak width varies in a similar but inverse pattern, so that the integrated intensity increases in a smooth curve from muscovite to montmorillonite. The major error in application of this quantitative method arises from uncertainty as to the correct allocation of peak areas in cases of overlap of the mixed-layer peak with those of discrete 10 Å and 14 Å clays also present.

The influence of pressure on the electrical resistivity of clay-water systems was investigated and found to reflect the abnormal nature of adsorbed water. The resistivity of montmorillonite—water systems varied with pressure in a manner similar to a dilute salt solution at pressures above 7000 psi. At pressures below this, abnormal pressure-resistivity relations resulted which were attributed to the presence of abnormal water associated with clay mineral surfaces. The pressure-induced breakdown of the abnormal water associated with montmorillonites was found to occur in abrupt stages as indicated by anomalies in the pressure—resistivity curves.

The anomalies indicated that layers of adsorbed water have differing degrees of structural bonding by which variations of the water-orientating ability of clay minerals may be compared. In general calcium montmorillonite was found to allow the most rigid bonding of the adsorbed water while sodium montmorillonite gave rise to the most extensive development of the abnormal water.

The abnormal water was found to re-form with some hysteresis effects when the pressure was released. An increase in temperature was found to decrease both the amount and the relative strength of the abnormal water.