bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of Hydroxyl Orientation, Stacking Sequence, and Ionic Substitutions on the Interlayer Bonding of Micas
Authors: Giese R. F. 
Published: August 2006

AbstractHydroxyl orientation has a major influence on the strength of the ionic interlayer bonding in micas because of the strong repulsion between the hydrogen and the interlayer cation (IC). In order to determine if other factors also influence the magnitude of the interlayer bond energy, the effect due to the varying H-IC distance, as one finds, for example, between a dioctahedral and a trioctahedral mica, must be removed. This can be done by calculating the bond energy as a function of the H-IC distance; a plot of which is a smooth curve with a minimum energy for the minimum H-IC distance. If there are no other factors which substantially contribute to the interlayer bonding energy, such curves for all micas should be superimposed. If, however, the curves are not superimposed but fall into groups with common attributes (stacking sequence, ionic substitutions, etc.) the energy separations between groups of curves indicate the influence of these other factors.The results of such calculations for four dioctahedral micas (2M1 muscovite, 3T muscovite, and two 1M muscovites) and four trioctahedral micas (2M1 biotite, 1M phlogopite, 2M2 lepidolite and a 1M MgIV mica) indicate that these curves are at higher energy for dioctahedral than for trioctahedral micas and this energy increase is due to the filling of the octahedral sites. The dioctahedral micas are arranged in terms of energy as 1M ≥ 3T ≫ 2M1 while the order for the trioctahedral micas is 1M ≥ 2M1 ≅ 2M2. In addition, the calculated energies suggest that the distribution of the layer charge between the octahedral and tetrahedral sheets affects the strength of the interlayer bond such that the greater the charge on the octahedral sheet, the stronger the interlayer bond.
The Orientation and Interaction of Ethylenediamine Copper (II) with Montmorillonite
Authors: Burba John L. , McAtee James L. 
Published: August 2006

AbstractThe d(001) spacings for a series of montmorillonite samples containing increasing amounts of Cu(en)32+ were recorded after exposure to 50% humidity, 10% humidity, and air that had been saturated with ethylene glycol. It was found that Cu(en)32+ is too large to fit between the montmorillonite particles and that in those samples with large amounts of ethylenediamine Cu(II) added, the clay platelets are associated with stronger interactions than those with small amounts of Cu(II) complex added.Infrared spectroscopy and electron spin resonance analysis indicate that the absorbed copper (II) complex is the square planar bis ethylenediamine Cu(II) and that the complex ion is oriented so that the dz2 orbital is perpendicular to the clay surface. The montmorillonite particles may act as ligands and coordinate with Cu(en)22+ ions.
Mössbauer Characteristics of Cambrian Glauconite, Central U.S.A.
Authors: Rolf Robert M. , Kimball Clyde W. , Odom I. Edgar 
Published: August 2006

AbstractMössbauer characteristics of 57Fe nuclei in 8 samples of mineral glauconite of Cambrian age and one sample of Cretaceous age (slightly disordered) were obtained at temperatures between 50 and 295 K to evaluate the site occupation of iron in the octahedral sheet and the Fe3+/Fe2+ ratio. It was found that the resolution of Mössbauer spectra of glauconite is increased at low temperature.The octahedral sheet in mineral glauconite is believed to contain two types of cationic environments with slight symmetry differences because of the position of oxygen and hydroxyl ions around the cation sites. One environment consists of two equivalent sites (M2), whereas the other is a single site (M1).The Mössbauer spectra were fitted to a four-doublet model, two Fe3+ sites (M2 and M1) and two Fe2+ sites, and a three-doublet model, two Fe3+ sites (M2 and M1) and an average Fe2+ site. The former (four-doublet) model yielded lower χ2 and, also, line widths in close agreement with previous studies. However, since the Fe2+ concentration in the samples is low, the error in intensity of the Fe2+ occupation of the M1 and M2 sites leads us to conclude that Fe3+/Fe2+ ratios are more accurate for the three-doublet model.Calculation of area ratios for the two Fe3+ doublets indicates that trivalent iron is strongly concentrated in the M2 site, which is smaller than the M1 site. Site preference of divalent iron could not be determined. The ratio of Fe3+/Fe2+ obtained from the Mössbauer spectra were usually within 8% of those obtained from chemical analyses.
Clay Petrology Of Cambro-Ordovician Continental Margin, Cow Head Klippe, Western Newfoundland
Authors: Suchecki Robert K. , Perry Edward A. , Hubert John F. 
Published: August 2006

AbstractThe sedimentary rocks of the Taconic Cow Head klippe contain three clay-mineral suites of progressively younger stratigraphic occurrence. An illite—14A chlorite suite is the oldest, occurring in the Middle Cambrian to early Lower Ordovician part of the 310-m Cow Head Breccia. These earliest clays were transported from the stable craton and shelf, slowly accumulating during 70 x 106 yr on the continental slope in limestone breccia, green and gray shale, and argillaceous limestone. The illite and 14A chlorite are judged to be largely detrital. An illite-expandable chlorite suite is in early to late Lower Ordovician limestone breccia, green and gray shale, and argillaceous limestone of the Cow Head Breccia. A corrensite-illite-smectite suite of late Lower to Middle Ordovician age occurs in the Cow Head Breccia and throughout the overlying 200-m ‘Red Shale’ and the more than 400-m ‘Green Sandstone’ flysch sequence of volcanogenic sandstone and gray shale. Beginning in the early Lower Ordovician, increasing amounts of Mg2+-rich volcanic detritus were rapidly transported westward from a developing volcanic island arc in central Newfoundland. During burial metamorphism, volcanic materials and their alteration products reacted to form the illite-smectite with 5–10% expandable layers plus corrensite or expandable chlorite found in the younger two clay-mineral suites.
A Relationship Between Crystallographic Properties of Illite and Chemical Properties of Extractable Organic Matter in Pre-Phanerozoic and Phanerozoic Sediments
Authors: Jackson Togwell A. 
Published: August 2006

AbstractCrystallographic properties of illite and chemical properties of organic matter in various mudstones ranging in age from Archean to Miocene were investigated. The breadth of the (001) X-ray powder diffraction peak of illite correlates significantly with the ratio of aliphatic to condensed-aromatic components and the degree of condensation of aromatic rings of the polar (“humic”) fraction of extract-able bituminous organic matter. The broader the diffraction peak, the less highly condensed and aromatic (i.e. less highly humified) is the organic matter associated with the illite. Breadth of illite diffraction peak and degree of humification of polar organic matter vary in a complex and apparently systematic way through geologic time. All of the three different suites of mudstones investigated (“calcareous,” “non-calcareous,” and “glacial” mudstones) gave similar patterns of secular variation. In addition, the ratio of diffraction intensities for the (002) and (001) reflections (I002/I001) of illite in calcareous mudstones and limestones showed a strong negative correlation with geologic age, indicating that the illites in the older rocks are enriched in magnesium with respect to aluminum.The correlation between crystal structure of illite and degree of humification of its associated organic matter could, by itself, be interpreted as an effect of post-depositional maturation processes, whereby “crystallinity” and degree of humification both increased as functions of heat and pressure. However, the patterns of secular variation suggest that the observed variations are primary, or were pre-determined by primary characteristics of the sample materials. The possibility that the original structure and composition of the organic matter influenced post-depositional changes in the crystallographic properties of sedimentary clay minerals, or post-depositional genesis of clay, would seem to merit consideration. The demonstrated relationship between crystallographic properties of illite and the nature of the “humic” matter constitutes evidence that most of the extractable organic matter is truly indigenous to the rock in which it occurs. The results also imply that molecular structure of extractable organic matter can be used in place of the breadth of the (001) diffraction peak of illite as an index of incipient metamorphism within a single formation or stratigraphic sequence, provided the primary characteristics of the organic matter are nearly the same in all samples. This method would have the advantage of being applicable to all sediments, not just those containing illite (specifically, aluminum-rich illite).The secular variation of the I002/I001 ratio of illite in calcareous sediments is provisionally ascribed to diagenetic processes whereby magnesium is abstracted from pore water and groundwater and is gradually assimilated into the crystal structure.
Exchangeable Cation and Solvent Effects Upon the Interlamellar Environment of Smectites: Esr Spin Probe Studies
Authors: McBride M. B. 
Published: August 2006

AbstractThe ESR spin probe, TEMPAMINE+, was used to study the interlamellar behavior of adsorbed organic cations on hectorites solvated with water, ethanol, and water-ethanol mixtures, and saturated with several monovalent and divalent metallic cations. The mobility and orientation of the probe was affected greatly by the solvent, and to a lesser extent by the predominant exchangeable cation on the silicate surface. Most of the effects could be interpreted in terms of the basal spacings of the hectorite. In all instances, the adsorbed probe was much less mobile than in solution despite the different interlamellar volumes available for molecular motion.
Note on the Intercalation of Kaolinite, Dickite and Halloysite by Dimethyl-Sulfoxide
Authors: Anton Octavian , Rouxhet Paul G. 
Published: August 2006

AbstractVarious kaolinites, a dickite and halloysites have been treated by DMSO in presence of D2O and subsequently washed by D2O. This procedure allowed to record OD stretching bands which are due specifically to the intercalated fraction and, for the washed samples, to the fraction of the solid which has been intercalated and has subsequently collapsed.No structural difference is found between the intercalated materials prepared from the various minerals. Washing usually restores the starting mineral; however, for a non-tubular halloysite, DMSO intercalation and subsequent washing gave a product similar to kaolinite.
The Exothermic Reaction of Metakaolinite in the Presence of Mineralizers. Influence of Crystallinity
Authors: Bulens M. , Delmon B. 
Published: August 2006

AbstractThis paper presents further results concerning the nature of the exothermic reaction of meta-kaolinite near 950°C. In a previous work (Lemaitre et al., 1975), we proposed that the exothermic effect had a double origin: (a) direct formation of mullite, promoted by CaO and (b) formation of a segregated spinel-type phase, i.e. γ-Al2O3, promoted by MgO.In this paper, we examine the influence of a further parameter on the reaction sequence, namely the crystallinity of the starting kaolinite as defined by Hinckley's index (c.i.; Hinckley, 1963). By combining X-ray and DTA techniques it is shown that the direct mullite formation path (a) occurs readily at 900°C in well-ordered kaolinite, but not in poorly ordered samples, even when fired with CaO. On the other hand, path (b) can be promoted in all samples using MgO as a mineralizer. When the indirect reaction path (b) occurs, a second exothermic effect is observed at approximately 1200°C indicating secondary mullite formation by recombination of segregated silica and alumina phases. This effect occurs in poorly ordered kaolinites even in the presence of CaO [path (a) promotor] indicating that path (b) is the most probable reaction mechanism in very disordered kaolinites.
Flouride Content of Clay Minerals and Argillaceous Earth Materials
Authors: Thomas Josephus , Glass H. D. , White W. A. , Trandell R. M. 
Published: August 2006

AbstractA reliable method, utilizing a fluoride ion-selective electrode, is described for the determination of fluoride in clays and shales. Interference by aluminum and iron is minimal. The reproducibility of the method is about ±5% at different levels of fluoride concentration.Data are presented for various clay minerals and for the <2-µm fractions of marine and nonmarine clays and shales. Fluoride values range from 44 ppm (0.0044%) for nontronite from Colfax, WA, to 51,800 ppm (5.18%) for hectorite from Hector, CA. In general, clays formed under hydrothermal conditions are relatively high in fluoride content, provided the hydrothermal waters are high in fluoride content. Besides hectorite, dickite from Ouray, CO, was found to contain more than 50 times as much fluoride (6700 ppm) as highly crystalline geode kaolinite (125 ppm). The clay stratum immediately overlying a fluorite mineralized zone in southern Illinois was found to have a higher fluoride content than the same stratum in a nonmineralized zone approximately 1 mile away. Nonmarine shales in contact with Australian coals were found to be lower in fluoride content than were marine shales in contact with Illinois coals.It is believed that, in certain instances, peak shifts on DTA curves of similar clay minerals are the result of significant differences in their fluoride content.
Scan Electron Micrographs of Kaolins Collected from Diverse Environments of Origin—IV. Georgia Kaolin and Kaolinizing Source Rocks
Authors: Keller W. D. 
Published: August 2006

AbstractScan electron micrographs (SEMs), are shown of three representative types of Georgia kaolin: ‘soft’, Cretaceous-age clay; ‘hard’, fine-grained clay; and ‘flint kaolin’.Sparta Granite and a thick deposit of its overlying saprolite are taken to serve as examples of probable source rock for Georgia kaolin. SEMs are presented to show sequential argillation of this fresh granite through a transition zone to the saprolite. The saprolite contains abundant books of kaolinite similar to those occurring in Cretaceous kaolin, accompanied by some elongates, whereas in the transition zone elongates are predominant. A morphologic type of fibrous, elongate 1:1 clay mineral, hitherto not illustrated, is shown from kaolinizing Sparta Granite, and from Pre-Cambrian saprolitic gneiss 25 km south of Athens, GA.Whereas kaolin elongates originated in contact with feldspar in the Sparta transition zone, well-formed books of kaolinite are shown to have been formed in contact with feldspar in the saprolite from a Missouri granite. The arkose above the granite in the Missouri occurrence has altered to loosely packed books of kaolinite. The interpretation is made that book-type kaolinite, where it occurs in large deposits of saprolite or kaolin, was formed under geochemical conditions of relative chemical stability between kaolinite and feldspar, as might prevail in a geological ‘weathering crust’. It is interpreted that elongate kaolin morphology may be formed under conditions of limited or lesser geochemical stability.SEMs show that the established book-morphology of Sparta saprolite is disarranged during secondary Holocene surface weathering and pedogenic processing.SEMs show that books of kaolinite, although individually fragile, may be protected from destruction or delamination during artificial blunging and transport when moved within naturally coalesced pellets. Possibly original books of weathered kaolinite might similarly survive natural stream transport during sedimentational processes.Some ‘flint kaolin’ contains molds of sponge spicules coated with low-cristobalite.
Scan Electron Micrographs of Kaolins Collected from Diverse Environments of Origin—V. Kaolins Collected in Australia and Japan on Field Trips of the Sixth and Seventh Clay Conferences
Authors: Keller W. D. 
Published: August 2006

AbstractScan electron micrographs are shown of the textures of flint clays, tonsteins, kaolin associated with combustion-metamorphism, sedimentary kaolin, and dickite from the Sydney Basin of Australia. The textures of the flint clays and tonsteins indicate those clays were derived largely from volcanic products. The clay samples were collected at stops on the Kaolin Excursion No. 4 of the August, 1976, International Geological Congress.In like manner, kaolin samples were collected in Japan from stops made on the field excursions of the Seventh Conference of the Committee on Correlation of Age and Genesis of Kaolin which met in Tokyo, September, 1976. SEMs illustrate representative kaolins of Japan, including Gaerome and Kibushi types of kaolin, Roseki (‘wax stone’) pyrophyllite and dickite, hydrothermal kaolin at Itaya, and flint clay at Iwate. Varied morphologies of halloysite, including spherical halloysite, from the Yamaka open-pit at Naegi are micrographed.Word descriptions of the textures are frustratingly inadequate in comparison to what may be seen at a glance in the micrographs—hence, the abstract becomes in reality a rapid view of the SEMs.
Contribution to the Adsorption Mechanism of Acetamide and Polyacrylamide on to Clays
Authors: Stutzmann Th. , Siffert B. 
Published: August 2006

AbstractWhile studying the retention of additives used in tertiary recovery of petroleum (waterflooding) on minerals present in a rock reservoir, an investigation has been undertaken into the adsorption mechanism of Polyacrylamides on to clays. The adsorption of amides and Polyacrylamides takes place exclusively on the external surfaces of the clay particles. The organic molecules are protonated on the surface and adsorbed by ionic forces. There is a linear relationship between the adsorption ratio and the polarizing power of the exchangeable cations of the clay mineral. The adsorption isotherms and the thermal analyses reveal the existence of two adsorption mechanisms: (i) a strong, irreversible adsorption, which corresponds to the formation of a monolayer of chemisorbed molecules, (ii) a more important adsorption of molecules retained by hydrogen bonding, which can be eliminated by heating at low temperature. The retention ratio in the irreversible process, which is practically identical both for acetamide and Polyacrylamide, is low (3 mg/g). It depends on the external cation exchange capacity (CEC) of the mineral and increases with the surface area. The Polyacrylamide adsorption depends on the physico-chemical characteristics of the macromolecule, more particularly on the CONH2/COO−ratio, which determines the extent of the carbon chain, and the molecular weight. The accessibility of the organic macromolecule to the clay particle is controlled by the preceding factors. The quantity of Polyacrylamide irreversibly adsorbed by clay minerals is important in the context of the use of the polymer on a petroleum field. It may be reduced to a minimum by working at low concentrations with a weakly hydrolyzed Polyacrylamide solution.
Surface Charge Characteristics of Amorphous Aluminosilicates
Authors: Perrott K. W. 
Published: August 2006

AbstractThe surface charge characteristics of a range of synthetic amorphous aluminosilicates, hydrous alumina, hydrous silica and two allophanic soil clays were determined by the retention of Na+ and Cl− as counter-ions from 0.1 M NaCl solution. In the pH range investigated (3–9), only negative charges could be detected in the hydrous silica and the most siliceous aluminosilicate [Al/(Al + Si) = 0.29], and only positive charges were detected in the hydrous alumina; whereas both positive and negative charges were detected in the more aluminous aluminosilicates and the soil allo-phanes. In all cases, the surface charges were pH-dependent and in the aluminosilicate series negative charge decreased and positive charge increased with Al/(Al + Si). Consequently, the point of zero charge increased with Al/(Al + Si).The charge characteristics of the amorphous aluminosilicates could be explained by current models of their structure. Negative charge can be attributed to isomorphous substitution of Al for Si in the silicate structure and to the dissociation of silanol groups in structural and adsorbed silicate. Positive charge is attributed to protonation of hydroxy-aluminum species occupying cation exchange sites.
Determination of Structural Defects in Phyllosilicates by X-Ray Powder Diffraction—II. Nature and Proportion of Defects in Natural Kaolinites
Authors: Plançon A. , Tchoubar C. 
Published: August 2006

AbstractUntil now, the different attempts to describe the defects of kaolinites were based on the ideas that (i) the hkl reflections with k = 3n are Bragg reflections, while (ii) the hkl reflections with k ≠ 3n are affected by ±b/3 translations or ±2π/3 rotations. With regard to this conception, this work provides several important precisions: (i) The h, 3n, l′ reflections are true continuous diffraction bands, more or less modulated, and disturbed by the existence, in the stacking, of random shifts parallel to the layer plane. (ii) The major defect in natural kaolinites is not the ±b/3 translation, but the displacement from one layer to the other (or from one domain to another in the same layer) of the Al vacancies. (iii) The model containing true rotation of layers should be rejected because it does not allow us to interpret all the different parts of the experimental diagrams. Such a concept of defects in kaolinites is in agreement with the existence of polytypes of kaolinite, with the presence of twins, and allows us to interpret some physico-chemical properties such as the infrared spectra.
Cross-Linked Smectites. I. Synthesis and Properties of Hydroxy-Aluminum-Montmorillonite
Authors: Lahav N. , Shani U. , Shabtai J. 
Published: August 2006

AbstractA stable porous system consisting of montmorillonite cross-linked by Al-hydroxide oligomers was synthesized by reacting at room temperature an aqueous solution of such oligomers with a unit-layer dispersion of montmorillonite. The resulting cross-linked montmorillonite (Al-CLM) is a nonswelling material, showing basal spacings of 14.4 to 18.8 Å after air drying and between 14.2 to 18.0 Å after treatment at 110°C. The basal spacing is found to depend on the age and OH/Al ratio of the Al-hydroxide solution, as well as on the relative amounts of the two reactants. A specific surface area of 160 m2/g and a diffraction pattern with a dominant basal spacing of 17.5 Å is obtained by using Al-hydroxide with OH/Al = 1.85, aged for at least 5 days, and by applying an Al/montmorillonite ratio greater than 1.5 in the cross-linking process. The basal spacing of Al-CLM remains essentially unchanged after heating at 220°C, while the specific surface area is not affected by heat treatment up to 480°C.Two possible configurations of Al-hydroxide oligomers, homogeneously distributed between parallel montmorillonite unit-layers, were considered in order to account for the basal spacing of 17.5–18.8 Å, viz. (a) stacking of two oligomeric ring units in parallel orientation relative to the clay lamellae and (b) perpendicular orientation of individual oligomeric units.
The Ordering of Cetylpyridinium Bromide on Vermiculite
Authors: Slade P. G. , Raupach M. , Emerson W. W. 
Published: August 2006

AbstractX-ray superlattice reflections, infrared spectroscopy, and chemical analyses have established that cetylpyridinium bromide (CPB) is highly ordered when adsorbed on vermiculite. The molecules, which stand at about 57° to the silicate surface, form close-packed arrays. Full surface coverage is achieved only for the most highly charged vermiculites. The packing within the arrays accounted for the superlattice observed and each adsorbed molecule had an area of 18.4 Å2 at the surface. The implications of these findings for the CPB method used in soil surface area studies are discussed.