bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron-Optical Study of Hydrothermal Fringe Alteration of Plagioclase in Quartz Monzonite, Butte District, Montana
Authors: Guilbert J. M. , Sloane R. L. 
Published: August 2006

AbstractPlagioclase feldspar is one of the outermost minerals destroyed in the hydrothermal alteration of quartz monzonite of the Butte district, Montana. Single grains of andesine plagioclase showing varying stages of fringe alteration were selected to show the sequence of events leading from the fresh plagioclase tectosilicate to the phyllosilicate montmorillonite, and to evaluate the role of petrographically-identified allophane in the alteration process.Replicas of fresh, incipiently, and thoroughly montmorillonitized grains reveal a complex sequence of events which may follow alternate equivalent paths. Quantitatively most important is the formation of a hobnail texture composed of sparse to dense ~0.5 μ discoids of amorphous material on feldspar cleavage surfaces. These discoids appear to fuse laterally to form amoeboid or lobate amorphous clusters. Some assume progressively more polygonal outlines characterizing the montmorillonite morphology, or their fringes become flake-like montmorillonite which peels away in wisps from the pitted feldspar surface. Wisps may persist singly, they may form minute ropy granules, they may develop into wispy ridges, or the entire surface may convert to ragged, wispy, or compact montmorillonite. Far less commonly, plagioclase appears to develop without a discernible amorphous stage. The alternative paths are probably influenced by the chemical activity of magnesium in the system.
Hydrothermal Alteration of a Rhyolite Flow Breccia Near San Luis Potosi, Mexico, to Refractory Kaolin
Authors: Keller W. D. , Hanson Robert F. 
Published: August 2006

AbstractA deposit of kaolin clay, the site of the General Zaragosa Mine, located about 50 km northwest of San Luis Potosi, S. L. P., Mexico, has produced more than 250,000 tons of refractory clay by room and pillar mining methods during the last 32 years. The clay was formed by hydrothermal argillation of part of a fault block of rhyolite flow-breccia and probably welded tuff, presumably lower Tertiary in age. A silica-rich gossan now exposed at the surface caps the clay deposit.Samples collected sequentially from the fresh rock to the most highly altered kaolin and studied by optical, X-ray, DTA, and chemical methods, show progressively:Bleaching of the breccia matrix accompanied by mobilization of much of the iron, which was concentrated locally as spots of reddish oxide in the least altered areas.Mobilization, and removal of considerable alkali and alkaline earth metals, in excess of that required to form montmorillonite; mobilization of silica, which was redeposited as fine anhedral quartz crystals disseminated within the montmorillonite and associated kaolinite-halloysite, or developed tripolitic, argillized rock peripheral to the clay ore body.Further desilication of the silica and clay yielding relatively pure, but poorly ordered, kaolinite-halloysite as the most intense end product of argillation. Much silica removed during intense argillation was reprecipitated as tripolitic clay, as minor cristobalite in microscopic globules and massive aggregates characteristic of colloform opal, and in vastly larger amounts as opal and chalcedony replacing the rock overlying the clay (forming a silica gossan).Minor amounts of alunite are present at two places in the deposit, which are interpreted tentatively as being the most probable loci of rising solutions.
Formation of Hydroxy-Al and -Fe Interlayers in Montmorillonite and Vermiculite: Influence of Particle Size and Temperature
Authors: Carstea D. D. 
Published: August 2006

AbstractHydroxy-Al and -Fe interlayers were prepared in “mono-mineralic” fine and coarse clay montmorillonite and coarse clay and silt vermiculite at 3°C and 21°C. The formation of hydroxy interlayers was evaluated by X-ray diffraction, cation exchange capacity, and chemical analyses.At comparable particle size and regardless of temperature, the amounts of hydroxy-Al and -Fe interlayers in montmorillonite exceeded by far those formed in vermiculite. Likewise, the aluminum systems exhibited a higher degree of interlayering than iron systems.Within montmorillonite, the amount of hydroxy-Al and -Fe interlayers increased as the particle size decreased, regardless of temperature. The aluminum interlayered montmorillonite equilibrated at 3°C was characterized by basal spacings of about 17 Å after Ca-saturation plus 54 per cent relative humidity. These spacings are larger than those normally observed for smectites.Within vermiculite systems equilibrated at 3°C, more hydroxy-Al interlayers were recorded in coarse clay than in silt fraction, whereas at 21°C about equal amounts of interlayers were formed. By contrast, hydroxy-Fe interlayer was favored by the silt fraction at both temperature levels.The formation of aluminum interlayers in both minerals increased with increasing temperature. The formation of hydroxy-Fe interlayers in montmorillonite was generally not temperature dependent, whereas the formation of such interlayers in vermiculite increased slightly with increasing temperature.These data may partially explain the formation of chloritic intergrades in soils as a function of type of minerals, kind of ions, and thermal variations.
Morphology of Particles in Sizefractionated Na- Montmorillonites
Authors: Roberson H. E. , Weir A. H. , Woods R. D. 
Published: August 2006

AbstractElectron microscopy of particles in size fractions (0·5–1·0 μ, 0·1–0·5 μ, 0·05–0·1 μ and < 0·05 μ e.s.d.) obtained by centrifugation of Na-saturated montmorillonites from Wyoming (two samples); Chambers, Arizona; and Fayette County, Texas, has shown details of particle morphology. The finest fraction of each montmorillonite consists predominantly of very thin, separate flakes whereas all coarser fractions, totalling 80 per cent or more by weight of the samples studied, are composed of microaggregates. For all the samples, preferred orientation is best developed in specimens formed from flakes of the finest fractions. Microaggregates are stable in dilute suspension although they swell to give large interlayer spacings, but can be disrupted into smaller, thinner flakes by ultrasonic vibration. Differences in dispersion behavior between separate flakes and microaggregates are not due to differences in interlayer charge or chemical composition, which are very small between fractions of each sample, but are thought to be due to the interlocking of flakes in microaggregates during crystal growth, which prevents their complete separation in dilute suspension.
Boron Fixation by Illites
Authors: Couch Elton L. , Grim Ralph E. 
Published: August 2006

AbstractThe mechanism of boron uptake by clays, especially illitic clays, and the factors which control such uptake have long been debated issues. In an attempt to answer some of the questions of the controversy, three illites were treated in solutions containing boron. In the study, boron concentration, salinity, temperature, and time were varied independently over rather wide ranges.For the illites studied, irreversible uptake of boron was increased by increasing boron concentration, salt concentration, temperature, and time of treatment. The amount of boron which was fixed also varied with the type of illite treated. The amount of fixation was controlled primarily by the specific surface area of the clay and also by the crystallinity, K content, and/or amount of mixed-layer material (“frayed-edge” development?), and apparently was independent of the original boron content of the clay.A two-step mechanism is proposed for boron fixation by illite, consisting of rapid chemical adsorption of the tetrahedral B(OH)4− anion at the “frayed-edge” of the illite flake followed by much slower diffusion of boron into the tetrahedral part of the structure.
Origin of the Woodstown, New Jersey, Macro-Kaolinite
Authors: Isphording Wayne C. , Lodding William 
Published: August 2006

AbstractA kaolin bed in which many of the individual kaolinite platelets exceed 0·2 mm in size occurs in the immediate vicinity of the base of the middle-Miocene Kirkwood Formation, near Woodstown, New Jersey. These platelets appear to have resulted from breakdown of pre-existing illite and montmorillonite coupled with concurrent epitaxial growth and diagenetic growth of primary kaolinite. The alteration of the clay minerals is thought to be a product of upward leaching (dialysis) by groundwaters in the underlying Vincentown Sand. This is further evidenced by abnormally high percentages of clay-size kaolinite in the clays that lie above the Vincentown Sand but beneath the macro-kaolinite horizon. Growth of the macro-kaolinite was facilitated by face-to-edge sédimentation and the resultant high permeability of the stratum.
The Use of Clay in Poultry Feed
Authors: Quisenberry J. H. 
Published: August 2006

AbstractDietary clay supplements (bentonite and kaolinite) have been used as binding and lubricating agents in the production of pelleted feeds for chickens. The high-swelling and water absorbing capacity of some bentonites make them attractive dietrary additives for control of wet droppings in caged layers. In addition, experiments show that layers fed on these diets exhibit significant increases in body weight, egg size, and life expectancy even though their total caloric intake is less than that of the control group. Dietary kaolin improves caloric efficiency even more than bentonite but without apparent effect upon growth or carcass quality. Kaolins of smaller particle size are superior to those of larger size in improving caloric efficiency. The effective kaolins are estimated to be worth approximately two calories of metabolizable energy per gram. The major beneficial effect appears to be due to a slowing down of the rate of feed passage through the intestinal tract. Possible uptake of trace elements required for optimum nutrition has not yet been evaluated.
A Morphological Study of Selected Synthetic Clays by Electron Microscopy
Authors: Warren Doris C. , McAtee James L. 
Published: August 2006

AbstractThe morphology of synthetic montmorillonite and hectorite was studied using electron microscopy and X-ray diffraction techniques. Interstratified montmorillonite-mica particles may be identified in these specimens by electron microscopy and electron diffraction techniques. Magnesium-substituted samples were found to exhibit an increasing amount of curling with increasing magnesium content except for the end-member magnesium clay. Synthetic hectorite clays do not necessarily have the same morphology as natural hectorite clays. A study was made also of the morphology of a series of samples obtained from a study of kinetics of crystallization. Boehmite and montmorillonite were the basic components of the system. It was found that the montmorillonite clay particles curled around the boehmite which had been adsorbed on the basal surfaces on the montmorillonite.
Glauconite Pellets: Similar X-Ray Patterns from Individual Pellets of Lobate and Vermiform Morphology
Authors: Tapper M. , Fanning D. S. 
Published: August 2006

AbstractGlauconite pellets of vermiform and lobate morphology occur together in Eocene geologic formations in Maryland. Morphologically, the vermiform pellets appear to be identical to those that have previously been called “altered biotite”. In thin sections these pellets do show a well-defined micaceous morphology with the layers running across the worm-like pellets. Some zones in these pellets appear to be “crystals” that are up to 30 × 70 μ and nearly rectangular in cross section. However, there are tiny cracks along cleavage planes within these “crystals”. Externally, the lobate pellets have many rounded lobes and are similar to one of the shapes that Burst has called free-form. In thin section under crossed nicols these pellets have a grainy appearance, indicating that the lobate pellets are composed of many small zones, each about 5–20 μ across. Within these zones the mineral glau-conite has a single orientation, but the zones are not lined up with each other to give the gross micaceous appearance that is associated with the vermiform pellets.Random powder X-ray diffraction patterns (prepared with a large 114·59mm Norelco powder camera) of individual vermiform and lobate pellets are nearly identical. Eight vermiform and 9 lobate pellets gave the same mean 001 (10·2 Å) and 060 (1·518 Å) spacings. The patterns from both kinds of pellets are similar, except for the absence of some weak lines, to Warshaw’s (ASTM) pattern for glauconite. The patterns have lines indicating a 1 M polytype, however, hkl lines with k ≠ 3n are broad indicating some disorder. In addition to X-ray diffraction patterns, the K2O content (6·7 per cent) and CEC (29 me/100 g as Ca replaced by Mg) of the pellets indicate that interstratified expanded layers may be the main source of the disorder.If the vermiform pellets are altered mica, the alteration has been sufficient to give a product that is definitely identified as glauconite by X-ray methods. The possibility of mica alteration is suggested by the geographic nearness of the Piedmont (a mica source area) and the occurrence of Piedmont-type quartz with the glauconite pellets. Alternatively, the vermiform pellets may form during glauconite crystallization or recrystallization processes. The probability that both kinds of pellets obtained their morphology before or during, rather than after, the time they became glauconite (mineralogically) suggests that the proper environment may form glauconite from a variety of starting materials.
Absorption of Pyrimidines, Purines, and Nucleosides by Li-, Na-, Mg-, and Ca-Montmorillonite (Clay-Organic Studies XII)
Authors: Lailach G. E. , Thompson T. D. , Brindley G. W. 
Published: August 2006

AbstractThe absorption of biologically important purines, pyrimidines, and nucleosides by Li-, Na-, Mg-, and Ca-montmorillonite has been studied in aqueous solutions over a range of pH values 2–12. The initial organic concentrations were about 1 m.molar. The ratio clay to organic compounds was such that only up to 25 per cent of the exchange capacity could be saturated by organic cations, but, depending on conditions, up to 100 per cent of the available organic material was absorbed. Of the nineteen compounds studied, only thymine, uracil, and their nucleosides were not absorbed under the experimental conditions. Absorption occurs primarily as a cation exchange reaction under acid conditions and varies with the basicity of the compounds, their aromatic or non-aromatic character, and the possible extent of their van der Waals interaction with the silicate layers. Nucleosides generally are less strongly absorbed than their purines or pyrimidines because their non-planar structure permits less van der Waals interaction; their absorption is influenced by the differences in swelling behavior of montmorillonite with mono- and divalent cations.
Cation Equilibria Studies on Fractionated Natural Clays
Authors: Fertl Walter , Jessen F. W. 
Published: August 2006

AbstractVarious fractions, ranging in size from 5 to 0·05 μ of natural clays from Mexico and Wyoming, occurring as heterogeneous or multicomponent cationic systems, were studied under specific equilibrium conditions of salt concentrations in the range found in many drilling fluids and formation waters.Glass electrodes were utilized in this study. A Tektite electrode was found to have specific sensitivity to divalent cations.
Low Frequency Dielectric Dispersion of Clay-Water-Electrolyte Systems
Authors: Arulanandan Kandiah , Mitchell James K. 
Published: August 2006

Abstract—The dielectric properties of saturated kaolinite clay-water-electrolyte systems were determined over the frequency range of 30–105c/s. Very large dielectric constants are observed at low frequencies. Since the experimental data approach constant values at each end of this frequency spectrum, they can be described by a fairly well defined spectrum of relaxation times. The particle size and orientation, the type and amount of electrolyte, and temperature affect the low frequency dielectric increment and the average relaxtion time. Several physical processes, such as relaxtion due to dipolar rotational polarization, interfacial polarization, free space charge and bound ion polarization, are examined in an attempt to explain the observed data. It is concluded that there exists at present no theory to explain all the data, but the bound ion polarization mechanism appears to explain some of the results.
Energy Dissipation of a Kaolinite at Different Water Contents
Authors: Franklin Arley G. , Krizek Raymond J. 
Published: August 2006

AbstractA Georgia kaolinite, at water contents from 55 to 95 per cent, was tested by means of a Weissenberg Rheogoniometer under conditions of pure shear with sinusoidally varying deformation over a frequency range of 3 decades. The results, including time-dependent effects, are expressed in terms of the magnitude of the complex modulus and the phase angle, as developed in the theory of linear viscoelasticity, and stress-strain hysteresis curves. The complex modulus is a two-component quantity, which has a real part associated with the elastic or energy storage characteristics of the material and an imaginary part associated with its viscous or energy dissipation characteristics. Although the complex modulus interpretation is very good for linearly viscoelastic materials, its applicability and usefulness diminishes as the material departs from linear viscoelastic behavior. On the other hand, the determination of energy dissipation from stress-strain hysteresis curves does not depend on any assumption concerning material behavior, because the area enclosed by the curve gives a direct measure of the energy dissipated in a single cycle of deformation. The dissipation characteristics obtained by the two methods are compared and used to illustrate the degree of validity and some limitations of linear viscoelasticity theory.
Mineralogical and Geochemical Study of Clay Mineral Transformations in The Sedimentary Triassic Jura Basin (France)
Authors: Lucas Jacques , Ataman Gürol 
Published: August 2006

AbstractA detailed study of sediments from the Triassic of the French Jura shows that clay minerals vary continuously with the facies. Near the coasts of the Jura Sea, sediments consisted of sandy, continental detritus and the minerals are poorly crystallized. At the center of the basin, in what was a cation-rich chemical environment, they are well crystallized. A progressive mineralogical variation can be observed from degraded illite to well-crystallized chlorites passing through the intermediate stages of more-or-less regular mixed-layer structures. This variation is due to a true crystalline transformation.Similarly, chemical variations in clay minerals and whole-rock samples are related to the paleogeography of the basin. The distribution of major and trace elements is a function of distance from the Jura Sea coastline and also a function of the mineralogical composition of the fine fraction. The most obvious relationships are: (1) An increase in the concentration of MgO and the percentage of ignition-loss water from the coast toward the deep sea; (2) A decrease in the concentration of SiO2, Al2O3, and TiO2 as well as that of trace elements such as vanadium, gallium, and cobalt from the coastal regions to the center of the basin; (3) A lack of statistically significant variations in the concentration of Fe2O3, Mn3O4, B, and Ni throughout the basin.The authors conclude that: ( 1 ) Transformations (aggradations) observed by means of X-ray diffraction methods are in agreement with the chemical analyses; (2) Transformations are contemporaneous with the sedimentation; they are not diagenetic; (3) Clay minerals play an important role in the geochemical balance of sedimentary basins.
X-Ray Spectrochemical Determination of Potassium in Clay Minerals
Authors: Johnson Leon J. 
Published: August 2006

AbstractAn X-ray spectrochemical method is compared with the flame photometer determination of potassium in a series of sixty-five soil clay fractions. Two methods of preparing the clay samples for the X-ray determination were used. In one case a 20 mg sample of clay in suspension was dried onto a plastic disc as a thin film. Potassium was determined by comparing the fluorescence intensity of the unknown with a sample of known composition which was prepared for analysis by the same technique. For the second method a 100 mg sample of dried clay was pressed into a pellet using methyl cellulose as a backing. In this case a National Bureau of Standards sample (NBS-98) was prepared in an identical manner and used as a standard for determining the potassium in the unknown. The results for both techniques were highly significantly correlated with the values as determined by flame photometric analysis. The pellet technique gave a more accurate measure of the potassium content. With the thin films the same sample may be used for X-ray diffraction analysis. In either case the X-ray spectrochemical technique provides a fairly rapid and simple procedure that can be useful for handling large numbers of samples.
Surface Acidity of Smectites in Relation to Hydration, Exchangeable Cation, and Structure
Authors: Mortland M. M. , Raman K. V. 
Published: August 2006

AbstractEquilibrium studies on clay films exposed to NH3 and H2O vapors demonstrate the effect of exchangeable cations on surface acidity and its relationship to hydration. At a relative humidity of 98 per cent the order of acidity on the clay surface as indicated by protonation of NH3 was Al > Mg > Ca = Li > Na = K for Wyoming bentonite and Al > Mg > Li > Ca = Na = K for nontronite. At a relative humidity of 20 per cent, however, the order was Al = Mg > Ca > Li > Na > K for the bentonite and Al = Mg > Li > Ca > Na > K for nontronite. The largest change in proton donation properties due to hydration effects was in the calcium clays. For Ca-bentonite the NH4+ formation was 16 me/100 g at 98 per cent and 80 me/100 g at 20 per cent relative humidity. In Ca-nontronite, the NH4+ formation was 14 and 64 me/100 g for the wet and dry systems respectively. The differences in proton donation between the bentonite and nontronite clays are believed to be due to charge site location and its effects on ion hydration. The NH4+ formed by the protonation process seemed to exist in different environments in the bentonite and nontronite as indicated in the i.r. absorption spectra.