bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micaceous Occlusions in Kaolinite Observed by Ultramicrotomy and High Resolution Electron Microscopy
Authors: Lee S. Y. , Jackson M. L. , Brown J. L. 
Published: September 2006

AbstractThe layer structure of kaolinite from Twiggs, Georgia and fire-clay type kaolinite (Frantex B, from France), particle size separates 2–0·2 μm was studied by high resolution electron microscopy after embedment in Spurr low-viscosity Epoxy media and thin sectioning normal to the (001) planes by an ultramicrotome. Images of the (001) planes (viewed edge-on) of both kaolinites were spaced at 7 Å and generally aligned in parallel, with occasional bending into more widely spaced images of about 10 Å interval. Some of the 10 Å images converged to 7 Å at one or both ends, forming ellipse-shaped islands 80 to 130 Å thick and 300 to 500 Å long. The island areas and interleaved 10 Å layers between 7 Å layers may represent a residue of incomplete weathering of mica to kaolinite.The proportions of micaccous occlusions were too small and the layer sequences too irregular to be detected by X-ray diffraction. The lateral continuity of the layers through the 7-10-7 Å sequence in a kaolinite particle would partially interrupt or prevent expansion in dimethyl sulfoxide (DMSO) and other kaolinite intercalating media. Discrete mica particles were also observed with parallel images at 10 Å, as impurities in both kaolinites. The small K content of the chemical analyses of the kaolinite samples is accounted for as interlayer K, not only in discrete mica particles but also in the micaceous occlusions.
Mineralogy and Origin of the Coalinga Asbestos Deposit
Authors: Mumpton F. A. , Thompson C. S. 
Published: September 2006

AbstractSince 1960 asbestos production of the United States has more than tripled, a phenomenon due in large part to the development of the Coalinga asbestos deposit in western California. Although most asbestos ores contain 5–10 per cent chrysotile in the form of cross- or slip-fiber veins within massive serpentinite bodies, no such veins are to be found in the Coalinga deposit despite the fact that it contains more than 50 per cent recoverable chrysotile. The Coalinga ore consists of soft, powdery, pellet-like agglomerates of finely matted chrysotile surrounding blocks and fragments of serpentinite rock. The highly sheared and pulverized nature of the ore favors its exploitation by simple, open-pit mining, and high quality products can be prepared by either wet or dry milling processes.Four types of serpentine material are distinguishable: (1) hard, dense blocks of serpentinite rock, ranging from fractions of an inch to several tens of feet in diameter; (2) tough, leathery sheets, resembling mountain leather, up to several square feet in size; (3) brittle blades and plates of green serpentine, a few square inches in size; and (4) friable agglomerates of soft, powdery chrysotile containing appreciable amounts of the other three. Chrysotile is the principal component of all the above materials, with the exception of the serpentinite rock which consists mainly of lizardite and/or antigorite, with small amounts of brucite, magnetite, and very short fiber chrysotile. Although chrysotile fibers up to several microns in length are present in the leathery sheets, most Coalinga chrysotile is much shorter and arranged in a swirling mesh or disoriented, tangled fibers, much like cellulose fibers in paper. Fragments of serpentinite gangue are scattered throughout the ore and contain most of the lizardite, antigorite, and brucite. Chemical, electron probe, and X-ray analyses confirm the iron-rich nature of the brucite, a critical factor in the susceptibility of this phase to oxidation in the surface weathering zone. Here brucite either dissolves, leaving behind a residue of brown, amorphous iron oxides, or transforms in situ to pyroaurite or coalingite. Dissolved magnesium precipitates as hydromagnesite immediately above the water table throughout the deposit.The abnormally high chrysotile content of this deposit is probably a result of the intensive shearing that it underwent during or after emplacement. If the friable, chrysotile-rich ore was produced during this pulverization episode, (1) lizardite and/or antigorite in the serpentinite must have been transformed into chrysotile and (2) brucite must have been removed. It is likely that early-formed lizardite/antigorite dissolved in the ground waters which pervaded the highly sheared body and that chrysotile later precipitated from these waters, coating all available surfaces.
The Relationship between the I.R. Spectra of Serpentines and Their Structures
Authors: Yariv S. , Heller-Kallai L. 
Published: September 2006

AbstractPossible assignments are suggested for some of the absorption bands in the 1150–400 cm−1 region of the i.r. spectra of serpentines. Polarized light was used to identify the out-of-plane vibrations in antigorites and platy lizardites and the vibrations parallel to the fibre axis in chrysotiles and fibrous lizardites. An attempt is made to correlate some known structural characteristics and the chemical composition of the serpentines with some features of the i.r. spectra.
Origin and Mineralogy Glacial and Interglacial Clays of Southern Norway
Authors: Rosenqvist I. Th. 
Published: September 2006

AbstractThe Numedal River basin (6000 km2) in central and east Norway contains 3 × 109 m3 of clayey material, corresponding to a clay loam sediment, which contains 2 million tons of absorbed rare earth elements.The clay mineralogy varies systematically from the till clays to a marine facies. It is concluded that the phyllosilicates of the clay fraction and tills originated from phyllosilicate minerals of the crystalline bedrock through a degradation partly due to preQuaternary weathering which dissolved a great part of the rock-forming minerals.
A Study of the Morphology and Properties of Aryl and Alkyl Ammonium Montmorillonites: An Electron Microscope Investigation
Authors: Jernigan Donald L. , McAtee James L. 
Published: September 2006

AbstractThe effect of exchanging selected aryl and alkyl ammonium cations for sodium ions on the morphology and the hydrophobicity of a sodium montmorillonite was studied. It was found that the morphology of the organo-clays as observed by transmission electron microscopy depended on the type of and the amount of exchanged organic cation. An attempt was made to correlate the observed morphology of organo-clays with their hydrophobicity.
The Relationship between Structural Properties of Metal-Tris (Ethylenediamine) Montmorillonite and Their Behavior as Gas Chromatographic Packing Materials
Authors: Thielmann V. J. , McAtee J. L. 
Published: September 2006

AbstractThe tris(ethylenediamine) complex cations of chromium(III), cobalt(III), and copper(II) were exchanged onto sodium montmorillonite. The resulting cation exchanged clays were dried, ground, sieved and the 50/80 mesh size was retained for use as column packing material to be used in gas chromatographic analysis of light hydrocarbons and oxides of nitrogen. Studies indicated that the hydrocarbons were following a sieving action whereas the nitrogen oxides were involved in a surface adsorption process.The changes in d001-spacing and surface area of tris(ethylenediamine)Cr(III)-montmorillonite were correlated with the changes in gas chromatographic retention time for the light hydrocarbons and the oxides of nitrogen.Retention time was obtained for the 100 per cent exchanged montmorillonites containing cations of tris(ethylenediamine)Cr(III), tris(ethylenediamine)Co(III), and tris(ethylenediamine)Cu(II). A comparative study of the d001-spacing and surface area of the three clays is shown to be directly related to the retention time.Heating effects were studied to determine thermal stability. Changes in retention times were compared with various structural changes. DTA and heating-oscillating X-ray powder diffraction analysis were used to help explain the relationship between retention time and structural change.
A Polarized Infrared and X-Ray Study of Lysine-Vermiculite
Authors: Raupach M. , Slade P. G. , Janik L. , Radoslovich E. W. 
Published: September 2006

AbstractLysine and vermiculite form a stable, ordered, interlamellar complex which has a well defined superlattice structure with respect to the ab-plane of vermiculite. The lysine molecules lie at a low angle to the silicate surfaces and establish a double layer network between such surfaces. I.R. and chemical data for the complex are given. The possible role of hydrogen bonds in linking the system together is considered.
Electron—Optical Investigations on Montmorillonites—II: Morphological Variations in the Intermediate Members of the Montmorillonite-Beidellite Series
Authors: Güven N. , Pease R. W. 
Published: September 2006

AbstractDioctahedral 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.
Water Vapor Isotherms and Heat of Immersion of Na/Ca-Montmorillonite Systems—I: Homoionic Clay
Authors: Keren R. , Shainberg I. 
Published: September 2006

AbstractAdsorption isotherms for water vapor, c-spacing and heat of immersion in water of Na- and Ca-montmorillonite were measured at 25°C at various r.h. The amount of water adsorbed as a function of the r.h. increased gradually, whereas the c-spacing increased, and the heat of immersion (per mole of adsorbed water) decreased in steps. There was good agreement between the calorimetric data, the heat calculated from the isotherms by use of BET equation, and the calculations from the ion-dipole model. A model is presented to describe the hydration of sodium and calcium montmorillonite.
Dissimilar Fabrics by Scan Electron Microscopy of Sedimentary Versus Hydrothermal Kaolins in Mexico
Authors: Keller W. D. , Hanson Robert F. 
Published: September 2006

AbstractDissimilar fabrics, observed by scan electron micrography (SEM) on freshly broken surfaces of kaolins from weathered, water-laid material vs hydrothermally altered material in Mexico are illustrated, contrasted, and tentatively related to their respective environments of genesis. Coarse, open-textured, well-preserved books and vermiforms of kaolinite characterize the kaolin from water-laid material at Jacal, Mexico. Hydrothermal kaolins tend to have more tightly compacted crystals of either kaolinite flakes (individuals or in packets) or elongates (halloysite morphology) or mixtures of both in the same deposit. Variations in porosity of parent rock whether sedimentary or igneous, and dissimilar permeation by meteoric water and by vapor and liquids of hydrothermal fluids are deemed to be significant in the processes producing distinctive fabrics. The question is raised as to the fundamental distinction between kaolinite and halloysite and their nomenclature.
Isomorphous Substitution of Iron for Aluminium in Some Soil Kaolinites
Authors: Rengasamy P. , Krishna Murti G. S. R. , Sarma V. A. K. 
Published: September 2006

AbstractClay (<2 μm) and fine silt (2–20 μm) fractions of twenty seven soil samples from eight tropical ferruginous profiles of the Mysore Plateau (India) were analysed for kaolinite by dehydroxylation and selective dissolution. The considerable amounts of iron extracted by the procedure and the closeness of the SiO2/R2O3 molar ratios (2·00–2·18) to the ideal value of 2·00 indicated that iron was a structural constituent of the kaolinites. The calculated unit cell cation composition of the kaolinites showed a substitution of 0·11–0·82 atoms of Fe(III) for Al in every four octahedral sites. The kaolinites in these soils appear to be products of crystallization from weathering solutions.
Hisingerite Occurring as a Weathering Product of Iron-Rich Saponite
Authors: Kohyama Norihiko , Sudo Toshio 
Published: September 2006

AbstractHisingerite occurs as a weathering product of iron-rich saponite in rhyolitic tuff of Oya, Tochigi Prefecture. The chemical composition: SiO2, 40·68%; Al2O3, 4·44%; Fe2O3, 28·54%; MgO, 1·85%; CaO, 1·42%; Na2O, 1·50%; K2O, 0·33%; H2O+, 6·43%; H2O−, 13·70%; total 98·89%. Very broad and weak X-ray powder reflections occur at 16, 4·5, 2·5, 1·7 and 1·5 Å, which correspond to the main peaks of nontronite. It is considered that trioctahedral iron-rich saponite was altered to hisingerite, a very poorly crystalline form of nontronite, by oxidation of iron and advanced leaching of octahedral Mg ions.
Od-Interpretation of Kaolinite-Type Structures—II: The Regular Polytypes (MDO-Polytypes) and Their Derivation
Authors: Dornberger-Schiff K. , Ďurovič S. 
Published: September 2006

AbstractAll MDO-polytypes (i.e. regular polytypes) of trioctahedral, dioctahedral and monoctahedral 1:1 phyllosilicates are derived from their OD-character using the results of our preceding paper. The terms ‘simple polytype’, ‘standard polytype’ and ‘regular polytype’ turn out to be synonyms of the term ‘MDO-polytype’ which has the advantage of being exactly defined. The method used to obtain the MDO-polytypes is also applicable to more complicated cases.
Heats of Compression of Clay-Water Mixtures
Authors: Kay B. D. , Low Philip F. 
Published: September 2006

AbstractHeats of compression of glass bead-water and clay-water mixtures were determined from the peak heights of the thermograms produced when these mixtures were subjected to pressure in a Calvet differential microcalorimeter. It is known that the heat of compression is directly proportional to the peak height. When the latter quantity was plotted against the pressure applied to any mixture, two intersecting straight lines were obtained. The change in slope at the point of intersection was interpreted as being the result of a pressure-induced higher-order phase transition in the water.The differential peak height, ε, was defined as the rate of change of peak height with pressure/g of water present in the mixture. Hence, it is directly proportional to the rate of change of the heat of compression with pressure/g of water. Values of ε were determined for both glass bead-water and clay-water mixtures containing different proportions of solids. It was found that ε remained nearly constant with increasing proportions of glass beads, whereas, it varied in a non-uniform way with increasing proportions of clay. Also, its values in the clay-water mixtures were relatively high. Calculations showed that the difference in ε values for the two mixtures could not be ascribed to the exchangeable cations associated with the clay particles. Consequently, it was ascribed to the effect of the particle surfaces on the structure of the vicinal water.
Evaluation of Bending Effects on Diffraction Intensities
Authors: Güven Necip 
Published: September 2006

AbstractThe effects of bending on diffraction profiles and intensities have been directly evaluated. It has been shown that:(1)bending may cause large reductions in intensities or even the total loss of them(2)due to bending, the profile of the reflection may become asymmetrical and it may display two or more maxima(3)bending effects vary with the class of reflections and they become larger with the increasing order of diffraction, and(4)the interference function for a bent lattice must be evaluated for each set of lattice parameters, whereas the interference function for an undeformed lattice can be made invariant with respect to lattice parameters.
The Mineralogy of Glauconite
Authors: Thompson Graham R. , Hower John 
Published: September 2006

AbstractThe mineral in monomineralic glauconite pellets is an iron-rich mixed-layer illite-smectite (here called glauconite), often composed almost entirely of illite layers. The nature of the interlayering is closely analagous to that of aluminous illite-smectite and varies with the proportions of the layer types: >30 per cent smectite, randomly interstratified; 15–30 per cent smectite, allevardite-like ordering; < 15 per cent smectite, ‘IMII’ ordering.Glauconite is analagous to aluminous illite-smectite chemically as well as structurally. A good correlation has been found between the number of potassium atoms per O10(OH)2 in structural formulas calculated from the chemical analyses and the proportion of illite layers as determined by X-ray powder diffraction methods. This relationship indicates a remarkably systematic increase in the potassium content of the illite layers with an increasing proportion of illite layers. This feature and the existence of ordered interlayering at high proportions of illite layers can be explained by crystal-chemical effects of illite layers on neighboring smectite layers. Glauconite differs from aluminous illite-smectite in that glauconite contains significantly less potassium per illite layer than does aluminous illite-smectite with the same proportion of illite layers except near the pure illite composition. The strength with which the interlayer potassium is held and the ease of conversion of smectite to illite layers in glauconite may be attributed to its 1M structure and, perhaps, to its high octahedral iron content, which lead to stronger bonding of potassium by allowing a higher tilt angle of the O-H axis of hydroxyls adjacent to the potassium ion.The apparent octahedral cation occupancy in excess of two-thirds of the octahedral positions in many glauconites appears largely attributable to the presence of significant amounts of interlayer hydroxy-iron, aluminum and magnesium complexes in the smectite layers.
The Composition of Kaolinite—an Electron Microscope Microprobe Study
Authors: Jepson W. B. , Rowse J. B. 
Published: September 2006

AbstractElectron microscope microprobe analysis (EMMA) has been applied to the determination of the elemental compositions of the kaolinite particles (Mg, Al, Si, K, Ti and Fe) contained in the 0·2-0·3 µm e.s.d., the 0·9-1·0 µm e.s.d. and the 1·9-2·0 µm e.s.d. fractions of an English kaolin and an American kaolin. Particles with masses as small as 10-13 g were analysed. An EMMA-4 instrument (A.E.I. Ltd.) equipped with linear fully focussing spectrometers was used. The ratio method of analysis was employed. The operating procedures used to obtain the required high experimental precision in the measurement of Al:Si atom ratio are discussed.Statistical analysis of the results gives the estimated mean and spread of the Al:Si atom ratios. In the English kaolin the mean Al:Si atom ratio differs from the ideal 1:1 at the 0·05 significance level. There is evidence for a variation in composition from kaolinite particle to kaolinite particle in the 1·9-2·0 µm fraction of each kaolin. In the 0·9-1·0 µm fractions, the mean Fe:Si atom ratio was close to 0·002 showing the presence of iron in the kaolinite structure. The mean K:Si ratio was about 0·002 which would be equivalent to 1 unit muscovite layer associated with a 0·175 µm thick kaolinite particle. In the American clay the Ti:Si atom ratio was 0·002 suggesting that some 12 per cent of the 'titania' found by conventional chemical analysis was associated with the kaolinite particles either as titania itself or as an isomorphous substituent.
A Kinetic Survey of the Cation Exchange and of the Oxidation of a Vermiculite
Authors: Besson G. , Estrade H. , Gatineau L. , Tchoubar C. , Mering J. 
Published: September 2006

AbstractWith the use of a BaCl2 solution containing radioactive Ba2+ ions, kinetics of cation exchange have been done on a Kenya vermiculite, natural on one hand and previously oxidized either by 50°C water or oxygenated water on the other hand. Correlatively, the quantity of ferric iron in the layer has been determined by E.P.R. These two methods have shown that during an oxidation the proportion of iron which stays in the octahedral layer depends upon the nature of the oxidizing agent. During a weak oxidation, the iron stays entirely in an octahedral layer and the exchange capacity of the vermiculite decreases; on the other hand, during an oxidation by oxygenated water, part of the iron is extracted from the octahedral layer and the exchange capacity of the vermiculite is not changed, as established by the studies of Farmer (Farmer et al., 1971). Kinetic data for Llano vermiculite also are reported and compared with those for the Kenya vermiculite.
Mineralogy and Genesis of the Wealdian Sediments in the Southern Cordillera Iberica (Spain)
Authors: Galan E. , Martin Vivaldi J. L. , Aguayo F. López 
Published: September 2006

AbstractThe present paper presents the mineralogical composition of sediments from the Spanish Wealdian facies, selected from four stratigraphic sections of several regions in the Southern Cordillera Iberica.Three of these sections show an irregular alternation of kaolinite rich sandy and silty-clay beds. The fourth section which contains calcareous layers, is very important from a geological point of view, because it is located where the structures of two ranges, the Iberian and the Betics, converge.The clays of about 80 samples from these sections always consist of illite, kaolinite and interstratified clay minerals. The sandy layers also contain quartz, as well as potash and calcic-sodic felspars. The fine fraction (< 2 µm) is composed of kaolinte, between pM and T types, swelling illite and randomly interstratified clay minerals of the type (10I-14M), richer in 10 Å layers.From the mineralogical and crystalchemical data and field observations, it is deduced that these sediments are mainly detrital. This and the layer alternation suggest, for the Upper Jurasic and Lower Cretaceous (Wealdian facies), a climate alternating from biostatic to rhexistatic. Alternating laterization and erosion might supply the materials to the Wealdian sedimentary basin.
Lithium-Bearing Tosudite
Authors: Nishiyama Tsutomu , Shimoda Susumu , Shimosaka Koya , Kanaoka Shigeto 
Published: September 2006

AbstractLithium-bearing tosudite was found from a brittle clayey part of the Tooho “roseki” deposit, Aichi Prefecture, Japan. The chemical composition of the Li bearing tosudite was estimated as SiO2 41·60%, A12O3 36·40%, Fe2O3 1·82%, MgO 0·29%, CaO 0·38%, Li2O 1·04%, Na2O 0·14%, K2O 0·38%, H2O+ 11·12% and H2O− 6·87% from the chemical composition of a specimen with associated impurities. The Li-bearing tosudite has the regularly interstratified structure of montmorillonite and dioctahedral chlorite in which Li is present in a gibbsite sheet as shown in the structural formula of interlayer cations K0·16, Na0·09, Ca0.13 + 9·60 H2O; gibbsite sheet Li1·36, Mg0·14, Fe0·45, Al3·59 (OH)12·00; silicate layer Al8·00 (Si13·60, Al2·40) O40·00 (OH)8·00. The 29·48 Å reflection series of the Li-bearing tosudite moves to 31·3 Å after ethylene glycol treatment and to 23·3 Å on heating to 500°C for 1 hr.