bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orienting Internal Standard Method for Clay Mineral X-Ray Analysis
Authors: Mossman M. H. , Freas D. H. , Bailey S. W. 
Published: August 2006

AbstractUse 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
Authors: Lang W. J. 
Published: August 2006

AbstractThe 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.
Some Results of the Study of Clay Minerals in the U.S.S.R.
Authors: Chukhrov F. V. 
Published: August 2006

AbstractClay mineral studies in the U.S.S.R., mainly since 1960, are summarized. Electron diffraction techniques especially have been developed and used extensively. Methods have been developed for simultaneous recording of DTA curves and other properties. Polytypism of phyllosilicates has been studied intensively by Zvyagin and others. Much new information on the structure and morphology of halloysites has been obtained by electron-optical methods. Other clay minerals extensively studied include allophanes, kaolinites, chlorites (“donbassite” is preferred to “sudoite” for dioctahedral varieties), alushtite (or tosudite), monothermite, and various zinc-bearing clays. Much attention has been given to physico-chemical and colloid-chemical properties. The natural occurrence and alteration of clays and clay minerals are described in weathering and oxidation zones, in soils, and in Recent and Ancient sediments. Primary clay minerals of hydrothermal origin are described.
Clay Minerals as Electron Acceptors and/or Electron Donors in Organic Reactions
Authors: Solomon D. H. 
Published: August 2006

AbstractCertain clay minerals have the ability to catalyze the polymerization of some unsaturated organic Compounds (styrene, hydroxyethyl methacrylate) and yet to inhibit polymer formation from other closely related monomers (e.g. methyl methacrylate). This apparently contradictory behaviour of the clay minerals can be rationalized in terms of electron accepting and electron donating sites in the silicate layers. The electron acceptor sites are aluminium at crystal edges and transition metals in the higher valency state in the silicate layers; the electron donor sites are transition metals in the lower valency state.The catalyzed polymerizations involve the conversion of the organic molecule to a reactive intermediate; thus where the clay mineral accepts an electron from the vinyl monomer a radical-cation is formed, where the organic compound gains an electron it forms a radical-anion. Examples of these reactions are discussed.The inhibition of polymerization processes involves the conversion of reactive organic intermediates, such as free radicals, which have been formed by heat or radical initiators, to non-reactive entities. For example, loss of an electron from the free radical gives a carbonium ion; in some cases this will not undergo polymerization. An example of this type is the thermal polymerization of methyl methacrylate.The color reactions on clay minerals are useful in predicting the electron accepting or electron donating behaviour of the clay minerals because they proceed by similar mechanisms to the polymerization reactions. For example, the benzidine blue reaction is a one electron transfer from the organic molecule to the electron accepting sites in the mineral (aluminium edges, transition metals in higher valency state).Masking of the crystal edge with a polyphosphate destroys the electron accepting properties of the crystal edge; this technique can be used to control the reactivity of the mineral and to distinguish between the crystal edge and transition metal sites as electron-acceptor sites in the clay minerals.
Relations of Composition to Structure of Dioctahedral 2:1 Clay Minerals
Authors: Weaver Charles E. 
Published: August 2006

AbstractA 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.
Hydroxyl Stretching Frequencies of Synthetic Ni-, Al-, and Mg-Hydroxy Interlayers in Expanding Clays
Authors: Ahlrichs J. L. 
Published: August 2006

AbstractInterlayers were produced in montmorillonite, vermiculite and hectorite in aqueous suspensions by precipitation from metal chloride salt, by hydrolysis of metal amalgams, and by slow hydrolysis of metal acetate during refluxing. In several systems an external phase of bayerite, gibbsite, or brucite was also formed. A prominent high frequency OH stretching vibration is associated with the interlayer in montmorillonites with approximate frequencies of 3660 cm−1 with nickel interlayers, 3690 cm−1 with aluminium interlayers and 3710 cm−1 with magnesium interlayers. Pleochroism studies indicate transition moment of interlayer OH to be at a relatively high angle to the planar surface of the clay crystals. Aluminium interlayers show some evidence of an additional weak absorption in the lower frequency region of 3570–3600 cm−1. In differential studies the lower frequency absorption is more evident and is shown to be unaffected by orientation. Techniques involving balancing of water deformation bands in differential spectra and D2O exchange suggest that it is not a water band. D2O flushing to remove water leaves the low frequency interlayer OH band more prominent in hectorite where the clay crystal OH is at 3680 cm−1. Deuteration studies show that flushing with D2O at room temperature removes water, and heating at 100°C in D2O vapor exchanges interlayer OH but not the clay crystal OH. Study of the OD stretching of the systems with deuterated interlayers supports observations made in the OH stretching bands.
Structural Charge Site Influence on the Interlayer Hydration of Expandable Three-Sheet Clay Minerals
Authors: Kerns Raymond L. , Mankin Charles J. 
Published: August 2006

AbstractPrevious investigations have demonstrated the influences of interlayer cation composition, relative humidity, temperature, and magnitude of interlayer surface charge on the interlayer hydration of montmorillonites and vermiculites. It has been suggested that the sites of layer charge deficiencies may also have an influence upon the amount of hydration that can take place in the interlayers of expandable clay minerals, if the interlayer cation-to-layer bonds are considered as ideally electrostatic, the magnitude of the forces resisting expansion may be expressed as a form of Coulomb’s law. If this effect is significant, expandable structures in which the charge-deficiency sites are predominantly in the tetrahedral sheet should have less pronounced swelling properties than should structures possessing charge deficiencies located primarily in the octahedral sheet.Three samples that differed in location of layer charge sites were selected for study. An important selection criterion was a non-correlation between tetrahedral charge sites and high surface-charge density, and between octahedral charge sites and low surface-charge density.The effects of differences in interlayer cation composition were eliminated by saturating portions of each sample with the same cations. Equilibrium (001) d values at controlled constant humidities were used as a measure of the relative degree of interlayer hydration.Although no corrélation could be made between the degree of interlayer hydration and total surface-charge density, the investigation does not eliminate total surface-charge density as being significant to the swelling properties of three-sheet clay-mineral structures. The results do indicate a correlation between more intense expandability and predominance of charge deficiencies in the octahedral sheet. Conversely, less intense swelling behavior is associated with predominantly tetrahedral charge deficiencies.
Surface Area of Montmorillonite from the Dynamic Sorption of Nitrogen and Carbon Dioxide
Authors: Thomas Josephus , Bohor Bruce F. 
Published: August 2006

AbstractSurface area determinations were made on a montmorillonite with various cations emplaced on the exchangeable sites, utilizing nitrogen and carbon dioxide as adsorbates at 77°K and 195°K, respectively, in a dynamic system. From the fraction of a Mississippi montmorillonite less than about 1 μ in size, samples were prepared by replacing the original exchangeable cations with Li+, Na+, K+, Rb+, Cs+, Mg++, Ca++, Ba++, and NH4+, forming a series of homoionic montmorillonite species.Surface areas from 3-point B.E.T. plots (half-hour adsorption points), with nitrogen as the adsorbate, ranged from 61 m2/g for Li-montmorillonite to 138 m2/g for Cs-montmorillonite, thus reflecting a certain degree of nitrogen penetration between layers. Complete penetration should theoretically result in a surface area of over 300 m2/g for this clay with a nitrogen monolayer between each pair of platelets. The experimental data indicate that the extent of penetration is time-dependent and is also a function of the interlayer forces as governed by the size and charge of the replaceable cation. This finding negates the generally accepted concept that nitrogen at 77°K does not penetrate the layers and provides a measure only of the external surface of expandable clay minerals.A further measure of the variation of interlayer forces is provided by the adsorption of carbon dioxide at 195°K. Surface area values ranged from 99 m2/g for Li-montmorillonite to 315 m2/g for Cs-montmorillonite. Although the carbon dioxide molecule is larger than the nitrogen molecule, its greater penetration apparently is a result of its being kinetically more energetic (with a larger diffusion coefficient) at its higher adsorption temperature. Similar differences have been found with both adsorbates in the study of microporous substances, such as coal, where activated diffusion is of considerable significance.
Differentiation of Pleistocene Deposits in Northeastern Kansas by Clay Minerals
Authors: Tien Pei-Lin 
Published: August 2006

AbstractSeventy-four samples from eight stratigraphic sections of lower Pleistocene glacial and glaciofluvial deposits in Doniphan County, extreme northeastern Kansas, were analyzed using X-ray diffraction techniques. Clay-mineral) assemblages of the <2 μ fraction of these deposits are nearly identical, consisting of a mixed-layer clay mineral associated with minor amounts of kaolinite and illite.An attempt was made to differentiate units of till and nontill deposits by using the relative intensities of 001 reflections of “mixed-layer mineral,” kaolinite, and illite. At least two tills were recognizable. Associated nontill deposits, could not be differentiated from one another, although the nontills are easily distinguished from tills.
Flint Clay and a Flint-Clay Facies
Authors: Keller W. D. 
Published: August 2006

AbstractFlint clay is defined as a sedimentary, microcrystalline to crystalline clay (rock) composed dominantly of kaolin, which breaks with a pronounced conchoidal fracture and resists slaking in water. Additional ceramic (refractory) properties are implied, but not expressed, in the definition. Flint clay first given recognition in the U.S.A., has been observed on all continents; it will probably be found to be more abundant than its occurrences reported to date. It occurs in rocks mainly Carboniferous or Cretaceous in age, and is invariably associated with plant- or coal-bearing measures.The environment of deposition is commonly lowlying paludal, in basins in either clastic silicate rocks or in karstic carbonates. It is inferred that parent illitic and/or kaolinitic clay colloids were transported into the swamps and there under-went further dialysis, alteration, and eventual crystallization in situ, producing a notably homogeneous kaolinite clay possessing interlocking crystallinity. Some occurrences were further desilicated to high-alumina minerals, particularly to diaspore and boehmite.Flint clay is interpreted as being an intermediate member of a so-called flint-clay facies which is a claystone sequence ranging from high-alumina minerals (or potentially so) formed on the highest part, structurally and/or topographically, of the depositional area, and grading down-structure and/or lower in elevation through flint clay to iliite-kaolinite plastic clay and thence to marine illitic shale, all being equivalent stratigraphically. The geochemical reactions are depotassification of parent clay by substitution of K+ by H+, and desilication, especially where high-alumina minerals are formed.
Effect of Al3+ and H+ Upon the Simultaneous Diffusion of 85Sr and 86Rb in Kaolinite Clay
Authors: Brown D. A. , Phillips R. E. , Ashlock L. O. , Fuquat B. D. 
Published: August 2006

AbstractThe effect of varying concentrations of Al3+ and H+ upon the simultaneous diffusion of 85Sr and 86Rb was measured in salt-free aliquots of clay having different Al:H ratios. The Sr and Rb saturation of the CEC was held constant while the exchangeable Al and H were varied from Al52:H1 to Al12:H34. Aliquots of each clay-treatment were dually tagged with 85Sr and 86Rb. Self-diffusion of Sr and Rb was measured at 4, 24, 48, and 75°C. Radioassay of 85Sr and 86Rb was made with an automatic gamma-detection system equipped with a 400 channel analyzer and card punch unit. The selfdiffusion equation was programmed for the 7040 computer to permit the simultaneous calculation of 85Sr and 86Rb self-diffusion coefficients. Rb diffusion was not significantly altered as the Al3+ concentration was increased from 12 to 52 per cent. The diffusion of Sr was significantly increased as Al3+ increased from 12 to 52 per cent. The faster diffusing Rb ion had a greater energy of activation than Sr (4·8 to 3·6 kcal/mole), however the Arrhenius frequency factor for Rb (a measure of the probability of ion exchange) was much greater for Rb than Sr (28·8 and 0·4 × 10−4, respectively). Altering the Rb and Sr saturation and the complementary ions resulted in changes in the diffusivity, the energy of activation, and the frequency factor for these ions, but not always in the same direction or to the same degree.
Surface Conductivity and Dielectrical Properties of Montmorillonite Gels
Authors: Weiler R. A. , Chaussidon J. 
Published: August 2006

AbstractThe surface conductivity of salt free montmorillonite clay gels saturated with lithium, sodium, potassium and cesium has been studied. The theory of the behavior of heterogeneous dielectrics adapted to systems having a surface charge density has been applied to the clay gels. From numerical calculations it became evident that the value of the depolarization factor may be extrapolated to 1 in the direction of the small axis of the platelet, meaning that the field action is zero in this direction. Along the long axis, however, the action is complete and the motion of the charge carriers is essentially tangential to the platelet. The values of the surface conductance are of an order of magnitude of 10−9 Mho.The investigation of the behavior of the water molecules has been carried out over a wide temperature range (145–320°K). At temperatures below 273°K, the conduction appears to be predominantly protonic; the counterions are considered to be disturbing elements in the water layer structures, thus creating a number of lattice defects able to transport the current. Above 273°K, the conduction is essentially due to the adsorbed cations, their contribution starts during the phase change.
Measurement of Exchangeable Cations in Bentonites
Authors: Rollins M. B. , Pool D. L. 
Published: August 2006

AbstractHigh swelling bentonites cannot be analyzed for exchangeable cations with exactly the same technique as most soils. To resolve varied techniques used in the past and to establish a reliable procedure, the effects of sample size, the number of saturations, washes and extractions, and the volume of extracting solutions were determined on three high-swelling bentonites.Small samples must be used to insure complete extraction of exchangeable cations, and the 0·5 g weight was the best size of those tested. Most exchangeable cations were removed in three extractions with 25 or 33 ml volumes of ammonium acetate. More extractions could result in excessive solubilization of minerals. Centrifugal force must be sufficient to prevent loss of sample during decantation. This varied from 4500 to 7500 g for 10–20 min, depending on particle size and sample dispersion.The proposed CEC method requires little time, but still compared closely with Frink’s more extensive method and showed no significant difference between treatment means. The procedure was used to analyze high-swelling bentonites from fourteen locations in six Western States. Chemical properties changed within each deposit and with geographical location, but in general the bentonites contained high amounts of exchangeable Na, moderate amounts of exchangeable Ca and Mg, and low amounts of exchangeable K. Total exchangeable reliability of the proposed method.
Weathering and Orientation in Triassic Clay Sediments of New Jersey
Authors: Lodding William , Sturm Edward 
Published: August 2006

AbstractThe composition of clay mineral suites derived from Triassic argillite and shale were compared with those of the consolidated parent sediments. Lockatong argillite, near the weathered zone, is composed mainly of illite, chlorite, and feldspar. In the clay horizon immediately above it, illite replaces the feldspar and kaolinite increases with distance from the contact until, near the top of the weathered zone, it is almost the only clay mineral present. A similar study was carried out on Brunswick shale. Here the parent rock consists mainly of illite, and some kaolinite, montmorrilonite, quartz, and feldspar. The kaolinite increases gradually as one progresses upward through the weathered zone, montmorillonite decreases, but approximately 30 per cent illite is still found in the top layers. Chlorite in the argillite near the weathered zone is randomly oriented while illite shows strong preferred orientation, probably indicating that chlorite formed in place during weathering. Illite in the Brunswick shale shows strong preferred orientation.These two Triassic sediments are less than 5 miles apart and one may assume that they had a similar post-depositional environment. The difference in diagenetic development is striking and must be attributed mainly to the chemical composition and lithology of the parent sediment.The orientation of clay particles in the solid rock was studied with the aid of an X-ray diffraction technique based on the analysis of cylindrical samples. Three-dimensional intensity data thus obtained were presented by vectors whose ends form a surface which is characteristic of the orientation of the particles. Generally the vectors generate hemispherical normal distributions whose principal vector coincides with the normal to the bedding plane.
Clay Minerals in Hydrothermally Altered Rocks at Wairakei, New Zealand
Authors: Steiner A. 
Published: August 2006

AbstractGeothermal fluid discharged by steam wells, which have been core drilled to depths as much as 4500 ft at Wairakei, New Zealand, has altered Pliocene to Pleistocene, silicic, mainly glassy volcanics and related aqueous tuffs and breccias. Measured temperatures (max. 265°C) indicate epithermal to mesothermal conditions in buried fault fissures, the locus of both the hydrothermal fluid and most intense alteration.A supergene kaolinite alteration zone is distinguished from hypogene Ca-montmorillonite and combined micaceous and chloritic zones. The hypogene zones are usually wide and are temperature dependent and localized along fault fissures. Other common hypogene minerals are alkali feldspars, wairakite, epidote, quartz, calcite, laumontite, ptilolite, pyrite and pyrrhotite. Prehnite is rare.The micaceous clay minerals include illite (about 10 Å) and a series of random mixed-layer illite-montmorillonites with d(001) values ranging from 10·28 to 12·45 Å. The amount of interstratified montmorillonite is related to temperature and fault fissures. Apart from rare mixed-layer swelling chlorite, the Fe-rich chloritic clay shows little or no variation in its composition. Both the micaceous clays and the chloritic clay result from alteration of earlier formed Ca-montmorillonite.The stability of hydrothermal minerals is controlled by the temperature and chemical composition of the geothermal fluid ascending along the fault fissures. K-feldspar but not albite is deposited on fissure walls, but both alkali feldspars replace primary soda-lime plagioclase in the wall rock. The absence of albite on fissure walls is ascribed to low aqueous mNa+/mK+ ratio. Primary quartz is not affected by the altering solution but hydrothermal quartz is deposited on fissure walls and in the wall rock.