The electron spin resonance (ESR) technique has been used to study the motion and segregation of an organic spin probe cation (4-amino-2,2,6,6-tetramethylpiperidine N-oxide) on K+-hectorite as a function of average surface concentration. The organic cation tends to concentrate in certain interlayers of aqueous hectorite suspensions even when it occupies a small fraction of the cation-exchange sites. This demixing effect is not evident in methanol-solvated hectorite. The average mobility of the probe increases at higher adsorption levels as a result of the shift of the equilibrium in favor of the solution state. Calculated time-averaged orientations of the probe on the clay surfaces are quite different for methanol- and water-solvated systems, emphasizing the importance of the solvent in modifying the surface-cation interaction.

Adsorption studies indicate that paraquat, diquat, and thionine are bound on bentonite by amounts greater than the measured cation-exchange capacity (CEC) of the clay. Methylene blue, new methylene blue, and malachite green are bound by amounts equal to the CEC. The unipositive organocations form aggregates on the clay surface. Aggregation increases with ionic strength and increases the apparent adsorption capacity by 25%. The aggregates are removed by washing with distilled water. Desorption studies show that the dyes are irreversibly bound, whereas the dipositive organocations are reversibly bound. Ionic strength variation reduces adsorption by 15 and 36% in the monovalent and divalent organocation-clay systems, respectively. In the clay-divalent organocation systems adsorption is greater on Na-saturated clay than on K-saturated clay. Adsorption is unchanged over the pH range 4.5–8.5 and decreases steadily below pH 4.0. Changes in adsorption due to changes in temperature are small. The study indicates that ionic strength is the most important variable in clay-organocation interactions.

Vermiculite, mixed-layer vermiculite-phlogopite, and smectite are presently forming from igneous and metamorphic bedrock in the alpine zone of the northern Cascades, Washington. In addition, south-facing exposures of quartz-diorites and metadiorites above snow line are weathering to ferruginous bauxite. Calculations indicate that vermiculite is presently forming from phlogopite schists in this environment at a unit area rate that is approximately six times the average estimated rate of clay erosion for North America. The mineralogical data indicate that chemical weathering in this region is a quantitatively significant process, and suggest that in the development of current geomorphic concepts researchers may have generally underestimated the importance of chemical weathering in alpine environments.

Sodium-lithium exchange equilibria between dilute aqueous chloride solutions and 0.2–62 μ Transvaal, South African vermiculite were studied at 25° and 50°C using a dialysis technique. The K content of the vermiculite was reduced to < 1% of the exchange capacity of 2·14 me/g by exhaustive extraction using Na-tetraphenylboron. The thermodynamic equilibrium constants and in turn the standard free energies and heats of exchange were evaluated from the equilibrium selectivity coefficients at the two temperatures. The standard entropy of exchange, ΔS°, was calculated according to the relationship ΔG° = ΔH° − TΔS°. Similar results were obtained for Na → Li and Li → Na exchange at 25°C, thus confirming the reversibility of the reaction.

Sodium preference increased with Na saturation of the vermiculite and equilibrium selectivity coefficients ranged from 6·0 to 22·0 at 25°C. In comparison, selectivity coefficients for Na-Li exchange on montmorillonite ranged from 1·0 to 2·0 and became smaller with increasing Na saturation. The standard free energy and heat of exchange on vermiculite at 25°C were −1444 and −5525 cal mole−1, respectively, resulting in a ΔS° value of −13·7 e.u. This relatively large entropy change is probably due to differences in ion hydration in the solution and surface phases.

A method using the bombardment of samples with protons and other positive ions of energy in the MeV range is described: the prompt atomic (γ-rays) and nuclear (γ-rays and charged particles) events generated during the bombardment, are detected with energy sensitive solid state detectors: cooled Ge(Li) for γ-rays and hard γ-rays, cooled Si(Li) detectors for soft γ-rays (3–20 keV) and Si-barrier detectors for charged particles. These 3 types of detectors can be simultaneously used for multipurpose experiments. These techniques are particularly useful for simultaneous detection of all the elements of interest in the sample. Comparisons are made with other microtechniques. Analyses of Li, Na, K, Ca, Rb, Cs and Cl exchanged in appropriate chloride solutions have been achieved for several clays (Geisenheim, Isola di Ponza, Layton). A new phenomenon relative to the anion contribution in cation exchangers is observed. A method of profile analysis of Na by resonant nuclear reactions is discussed.

The Āl-i Burhān, who held the religious leadership (ṣadāra) of Bukhara from the end of the fifth to the middle of the seventh century A.H. (eleventh to thirteenth century CE) and were the religious and secular leaders of the city, are known to us through a number of studies by Bartold, Qazvīnī, and Pritsak.1 However, at least two other pieces of information about this family's background are available in two recently published books that were not available to these scholars. The first book is al-Qand fī ḏikr ʿulamāʾ Samarqand (henceforth al-Qand) by ʿUmar ibn Muḥammad al-Nasafī (461‒537 A.H./1069‒1142 CE), and the other is Laṭāʾif al-aḏkār li-l-ḥużżār wa-l-suffār fī al-manāsik wa-l-ādāb (henceforth Laṭāʾif) by Muḥammad ibn ʿUmar ibn ʿAbd al-ʿAzīz (511–566 A.H./1117‒1170 CE), the greatest religious leader (ṣadr) of this family in the sixth century A.H. (twelfth century CE).2 The latter, precisely because it was written by the greatest and most powerful member of the family, contains some firsthand information about the family itself and the scholars of Bukhara that appears to be unique, and the former provides the most detailed extant information about the scholars who lived in Samarqand or visited that city until the mid-sixth century A.H. (twelfth century CE). Al-Qand also incidentally contains some information about the first ṣadr of the Burhān family, which has neither been seen elsewhere nor noticed by scholars since the publication of the text in 1999.

This paper documents the first report of flint clay in Mexico, located at Estola, Guerrero, 199 km south of Mexico City, on Mexico Highway 95. It is the first report (known to the writers) of flint clay formed by hydrothermal alteration. It describes the in-situ alteration of a calcareous, silty shale to flint clay (well-ordered kaolinite).

The changes during alteration are mineralogical, chemical, and structural. Calcite, comprising about one-third of the shale, quartz and probably some feldspar comprising a scant third, and a mixture of greenish-yellow (limonitic) clay minerals are dissolved or altered ultimately to white kaolinite (monomineralic). Calcium carbonate, free and combined silica, and iron compounds are dissolved, while simultaneously the alumina is relatively enriched. The fissility, inequigraularity, and cementitous fabric of shale are changed to the massively homogeneous, finegrained, interlocking fabric that is typical of flint clay.

The sequence of changes, which overlap, are; (1) dissolution of carbonate minerals, (2) mobility of iron, replacement of quartz and feldspar by kaolinite; and (3) intensive “digestion” of rock substance to homogeneous, essentially monomineralic, kaolinite flint clay. Alunite, and secondary vein-calcite or gypsum may accompany the flint clay.

This occurrence lends support to the concent that flint clay is formed from presumably only sedimentary parent rock.

Dioctahedral aluminum smectites from bentonite deposits in Argentina, Brazil, Czechoslovakia and Japan represent, according to the MgO content of the bulk samples, intermediate members in the montmorillonite-beidellite series. The smectite particles in these samples occur in a variety of forms such as; (a) laths and diamond-shaped units with a well developed crystal habit, (b) loosely folded aggregates with an irregular morphology and (c) flat and compact lamellae with well developed {001} forms but with complete lack of {hk0} forms. Such lamellae have been described in two groups: the thin ones (10–50 Å) and the thicker ones. Thin lamellae may give SAD spot patterns with a non-hexagonal symmetry. Lamellae having thicknesses greater than 50 Å resemble a single crystal but their SAD patterns indicate that they do not have a three-dimensional periodicity.

The question arises whether the morphologically different particles in a sample belong to the same intermediate phase or if they represent different members in the montmorillonite-beidellite series coexisting in the same sample.

This is the transcript of an interview with Glasgow-based Australian composer Dr Jane Stanley. The interviewer is Dr Judith Bishop, an Australian poet and lyricist whose words appear in two of the works discussed: ‘14 Weeks’ (from Interval (UQP, 2018) and ‘The Indifferent’ (from Event (Salt Publishing UK, 2007)). The interview was recorded at the University of Glasgow on 29 May 2023 and edited for clarity, length and concision. It was recorded a day after the world premiere of Jane Stanley's 14 Weeks at the Glasgow School of Art Choir Composeher concert in City Halls, Glasgow. In response to a recent survey which revealed huge gender inequalities in the granting of music commissions, Composeher had commissioned seven female composers to write choral works of around ten minutes, of which 14 Weeks was one. The interview ranges widely, from the composer's textural style to her creative process, and touches on her forthcoming composer portrait album, to be released by Delphian Records in 2024.

At low levels of hydration, exchangeable D+ in montmorillonite interacts with lattice OH groups and quantitatively converts AlMgOH groups to AlMgOD. Hydroxyl groups coordinated to two Al ions undergo a slower exchange, the extent of which is restricted by octahedral Fe3+ ions. The OH stretching vibration of AlMgOH groups in montmorillonite is assigned an unusually high frequency (3687 cm−1) compared with that of the same group in phengites (3602 cm−1).

Spray drying dilute suspensions of bentonitic montmorillonite produces a powder that shows totally random orientation of the crystallites within a sample large enough to diffract X-rays. The powder is collected by an electrostatic precipitator and can be handled in the normal mounting processes without introducing preferred orientation. Electron micrographs show this powder to be composed on a small scale of thin, crumpled, and rolled films. The extremely small montmorillonite crystallites that make up the film are oriented with [001] directions perpendicular to the film surface. Orientation within the plane of the film is random as shown by selected area electron diffraction. Crumpling and rolling of the film is sufficient to make the orientation of [001] directions random in three dimensions in a large sample when X-ray diffraction is registered.

The X-ray diffraction patterns all show diffraction maxima (both hk and 00l), and their relative intensities with respect to each other can be determined. The line broadening of the 06 and the 003 peaks was studied. The average crystallite size as calculated from the line broadening varied from six to eleven unit layers thick for four bentonitic montmorillonites. The average lateral dimension of crystallites varied from 140 Å to 250 Å. Ratios of lateral dimensions to thickness varied from 2.3 to 3.4.

Clay fractions from four soils were analyzed for kaolinite and gibbsite by differential thermal analysis (DTA) and selective dissolution analysis (SDA). The kaolinite values by the two methods had a standard deviation of ±0.95 for the 2–0.2 μ clay of the three most highly weathered soils. Apparently some kaolinite was dissolved with amorphous material in the 0.2–0.08 μ kaolinite standard and probably in 0.2-0.08 μ soil clays. Accuracy of kaolinite determination for the 0.2–0.08 μ soil clays by DTA was reduced because of uncertainty of exact composition of the standard. Presence of montmorillonite in Sango soil clays, particularly the 0.2-0.08 μ fraction, apparently contributed to the error in kaolinite determination by SDA. More precise values for gibbsite were obtained by DTA than by SDA because of the dissolution of alumina from sources other than gibbsite.