The nature of Cr(NH3)63+ and Cr(en)33+ (en = ethylenediamine) adsorbed on chlorite, illite, and kaolinite has been studied by X-ray photoelectron spectroscopy (XPS). The interaction of the chromium complexes with the clays began at pH 3. During the 7-day interaction time the pH of the complex-clay suspension increased to 8 for illite and chlorite. For kaolinite the pH increased to about 3.6 with Cr(NH3)63+ and to 6.4 with Cr(en)33+. These pH changes appear to be associated with a clay-catalyzed hydrolysis of the chromium-amine complexes. XPS binding-energy data for adsorbed chromium indicate that the dominant species are chromium aqua complexes. Nitrogen/chromium atom ratios, calculated from the XPS photopeak intensities, are less than 6:1 for complexes adsorbed on the clays, suggesting that chromium complexes are initially adsorbed but subsequently hydrolyze to produce aqua-chromium surface species.

Mössbauer spectra of 9 glauconite samples from Upper Cretaceous and Lower Tertiary strata in the South Island of New Zealand contain a broad shoulder due to low intensity absorption continuous between 1.0 and 2.5 mm/sec when the absorber is at room temperature; the shoulder is absent, and sharp peaks are apparent in spectra taken with the absorber at 80°K. The data suggest that electron transfer occurs between adjacent Fe3+ and Fe2+ ions at room temperature. The low temperature spectra indicate that all Fe in the glauconites is in octahedral coordination. Fe3+ and Fe2+ ions occur in both eis and trans sites; Fe3+ shows a strong preference for eis sites whereas Fe2+ shows an even stronger preference for trans sites.

The partially variable oxidation state of Fe in glauconite is interpreted in terms of a geochemical model for glauconitization of a degraded or incomplete progenitor phyllosilicate. The model involves exchange of Fe2+ for other cations which temporarily stabilize the progenitor, followed by Fe2+-Fe3+ charge transfer reactions. Each reaction results from the system's tendency towards equilibrium. The model is supported by the observation that artificially leached glauconite increases both its Fe3+ and its Fe2+ content when placed in a solution containing Fe2+ as the only Fe ion present.

The flint-clay facies, originally proposed from widespread stratigraphie evidence, is represented by four of its six members within a single commercial deposit of Cheltenham refractory clay in Missouri. Scan electron micrographs show progressive changes in texture from plastic refractory clay (as in ball-clay “swirl” texture) through semi-plastic, semi-flint, to typical flint clay (recrystallized, well-ordered kaolinite). Micrographic evidence supports the interpretation of the origin of the Cheltenham clay earlier made from field and macroscopic evidence. Source material from nearby residual, weathered clay was transported into paludal basins, “digested,” partly recrystallized to kaolinite, brecciated and reconsolidated, essentially completed before being covered by younger Pennsylvanian-age sediments.

The natural tidelands sediments along the north shore of San Pablo Bay, California, are neutral in reaction and subjected to a wet, reducing environment conducive to ferrous sulfide accumulation. When the sediments are diked and drained, the environment rapidly becomes oxidizing and generally dry. Oxidation of the ferrous sulfide results in extremely acid cat clays within a year or two.

Undrained sediments from the area contain montmorillonite, chlorite, mica, and kaolinite that all give sharp X-ray diffraction patterns. Sediments drained for 6 years, although strongly acid, have virtually the same clay mineralogy as the undrained sediments. However, sediments drained for 60 years show a general deterioration of crystalline clay minerals, particularly chlorite. The deterioration decreases with depth until the deeper zones closely resemble the undrained sediments.

In separate laboratory experiments, chlorites were formed in an oxidized soil that was subjected to reducing conditions simulating the environment of the undrained tidelands sediments. The possibility exists, therefore, that chlorites in the undrained sediments may have formed subsequent to deposition.

Clay fractions in soils from a transect of the Mazama ash deposit (6600-yr-old) contained more than 80% amorphous material. Instrumental neutron activation analysis was used to compare the trace element composition of the soil clay with the unweathered volcanic glass. The clay fractions had only 10% as much Na as the volcanic glass. Conversely, the rare earth element concentrations were about three times greater and the transition metal concentrations were up to nine times greater in the clay than in the glass. The < 2μ size fraction therefore contained mostly weathering products rather than fine glass.

The abundances of Cr, Co, Sc, and Fe in the clay fraction decreased with depth. The Sc/Fe ratio was approximately 4 × 10−4 for both clay and the unweathered glass. The relationship between elemental concentration in clay and fine sand size separates from the same soil horizons indicated that the clay exists in association with the larger size particles, probably as coatings.

Dilute nitric acid removed about 80% of the rare earth elements La, Nd, Sm, Eu, Tb, Yb, and Lu from the clay. Deferration was necessary to remove Ce, a rare earth element that forms insoluble oxides upon oxidation to the Ce4+ state. The residue of the KOH dissolution treatment contained 2:1 layer silicates that may be derived from primary biotite.

Exchange isotherms for the pairs Na-K and Na-Ca were measured by use of 0.1 N solutions at 5°, 35°, and 70°C in phillipsite from Tecopa, California (3.63 Al/32 oxygen unit cell), and Oki Islands, Shi-mane Prefecture, Japan (6.31 Al/32 oxygen unit cell). All isotherms except those for Na-Ca at 5°C were reversible. Free energy was evaluated for all reversible exchanges. The thermodynamic affinity sequences were K > Na > Ca in both phillipsites. The selectivity for K in competition with Na and that for Na competing with Ca became larger at the lower temperatures. The siliceous phillipsite preferred the larger cation more strongly for the Na-K system, and Na more strongly for the Na-Ca system than the aluminous phillipsite.

A ternary plot of the tetrahedral R3+ and octahedral R3+ populations for the dioctahedral 2:1 clay minerals shows a broad range of compositional variation within each of the major clay minerals. The clay minerals can be subdivided on the basis of total charge, location of the charge, and the relative amounts of Al and Fe3+ in the octahedral sheet. The division is natural and is controlled by the misfit between the tetrahedral and octahedral sheets and the need for tetrahedral rotation. The compositions of the tetrahedral and octahedral sheets are interdependent. Whereas muscovite has a lower limit of 1·7 Al octahedral occupancy, illite and montmorillonite have a lower limit of 1·3 Al; lower Al values result in the formation of a chain structure.

In the spirit of Béla Bartók and Zoltán Kodály’s work, Miklós Both has been collecting folk songs in Ukraine since 2013 with the help of an international research group. The results of the collecting trips are available in the form of a modern, user-friendly online database that supports both scientific use and public education. The collection received a lot of publicity in 2017 when the Polyphony Project website was launched. The 2022 Russo-Ukrainian War also put the enterprise in the spotlight. This review highlights the scientific and pedagogical usability and importance of the Polyphony Project.

A hydromuscovite in association with gypsum and anhydrite was collected from the Shakanai mine, Akita Prefecture, Japan. Chemical composition: SiO2 47·14%; TiO2 0·34%; A12O3 37·09%; Fe2O3 0·49%; MgO 0·83%; CaO 0·57%; Na2O 0·35%; K2O 7·10%; H2O+ 5.18%; H20–0·99%; P2O5 0·01%; total 100·09%. Differential thermal and i.r. absorption analyses were similar to those of hydromuscovite. The X-ray diffraction pattern differed clearly from those of the 1M and/or 2M1 polymorphs and it was similar to that of the 2M2 polymorph, which is known to occur in lepido-lites.

Die Untersuchung der Schöpfungsthematik in der Didache ist ein Forschungsdesiderat. Daher werden Übersetzungen und Kommentare daraufhin überprüft, welche griechischen Wörter an welchen Stellen schöpfungstheologisch interpretiert werden. Dieses vorläufige Netz der Schöpfungsterminologie wird durch weitere Analysen verfeinert, um einen Gesamteindruck der Schöpfungstheologie zu gewinnen. Im schöpfungsethischen Ausblick wird die Frage herausgegriffen, wie es für die Didache zukünftig mit der Schöpfung weitergeht, was im Horizont gegenwärtiger Herausforderung besprochen wird. Die Didache hat weder ein vordergründig ökologisches Interesse noch eine pauschale Abwertung der gegenwärtigen Schöpfung. Dennoch steckt in der Didache ein ökotheologisches Potenzial.

Vermiculites and smectites in soils and sediments are frequently partially interlayered or “chloritized”. Dioctahedral expansible layer silicates are those most frequently interlayered, and hydroxy-Al appears to be the principal component of the non-exchangeable interlayer material.

The most favorable soil conditions for interlayer formation appear to be: moderate pH (4·6–5·8), frequent wetting and drying cycles, and low organic matter content.

In marine sediments, hydroxy-Mg interlayering may be significant. Soil-derived clays containing partially filled hydroxy-Al “brucite” sheets may be filled out with hydroxy-Mg. Under reducing conditions, hydroxy-Fe interlayers may be important.

Depending on the OH/Al ratio and Al content of hydroxy-Al interlayers, expansible layer silicate may either promote or retard the formation of gibbsite. Interlayered expansible layer silicates also may be precursors to kaolinite.

Treating NH4-bentonite with diazomethane results in methylation of adsorbed ammonium with the formation of the tetramethylammonium ion. This ion, which can be completely removed through ion exchange, is distinguished in the IR spectrum by a strong band at 1480 cm−1 due to CH3 group bending vibrations. X-ray diffractograms, CEC, and surface area of the clay are not modified by treatment with diazomethane.

I.R. band shifts in the 830, 750 and 530 cm−1 regions that occur in interstratified layer silicates on heating were used to characterize the nature of the component layers. Two specimens showed shifts characteristic of 1 M illite and montmorillonite. Another specimen was similar to 2M illite even though the proportion of expanding layers was 0·4. The shifts for rectorite and allevardite resembled those of paragonite and 2 M illite.

0.5 molal iron(III) chloride solutions were hydrolysed at room temperature by base additions in the range OH/Fe mole ratio 0–2.75. After an ageing period the hydrolysed solutions were used to produce amorphous hydroxide gels from which crystalline products were grown at 65°C, at low pH or high pH. Examination of crystal composition and morphology and comparison with similarly treated nitrate solutions showed that the nucleation of hematite and goethite is inhibited in chloride containing solutions, which allow growth of small rod shaped β-FeOOH to predominate or occur exclusively in gels at pH 1–2. The addition of seed crystals of hematite and goethite allows competitive growth of all three minerals. The transformations β-FeOOH → α-Fe2O3 and β-FeOOH → α-FeOOH at pH 1–2 proceed by dissolution and reprecipitation and are promoted by adding seed crystals.

The viscosity of certain kaolin—water systems was correlated with natural montmorillonite content of the kaolin, as determined quantitatively by the Hinckley—Bates (1960) strontium-exchange technique. Transition from low viscosity to high viscosity occurred when montmorillonite content of the Georgia clays studied exceeded 5%.

Orange-yellow detrital flakes of biotite are common carriers of potassium and trace elements in soils and clays. Because the flakes differ in degree of alteration and may be derived from different sources, it is difficult to obtain homogeneous material for studies of their physical and chemical properties that may be compared with the original mica. A similar orange-yellow altered biotite occurs with fresh biotites in alkalie rocks of a nepheline deposit. The fresh and altered biotites were separated for chemical and minoralogical studies of the effects of weathering on biotite in its parent rock.

The common iron-rich biotites with octahedral occupancy between 5.5 and 5.8 alter to bright orange-yellow biotites with octahedral occupancy approaching five. These biotites, intermediate between the trioctahedral and dioctahedral micas, form as a result of oxidation during the process of their alteration to chlorite—vermiculite.

Biotites with octahedral occupancy approaching five were prepared experimentally by heating a natural biotite that contained high ferrous iron. The main differences between the natural and laboratory oxidized biotites are: the naturally oxidized micas lose 30% of the original potassium, adsorb about 2 wt.% water, and apparently gain about 25% hydroxyl, whereas laboratory oxidized micas retain potassium and lose hydroxyl and argon. The oxidized micas retain the crystal structure of the original mica.