bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ordovician K-Bentonites of Iowa
Authors: Mossler John H. , Hayes John B. 
Published: August 2006

Abstract
Thin beds of altered volcanic ash, called
K-bentonite, are distributed widely in Ordovician strata of the eastern
United States. This study reports the mineralogy and stratigraphy of eight
such beds found in limestones and shales of the Decorah and Galena
formations (Middle Ordovician) of northeast Iowa and adjacent parts of
Minnesota, Wisconsin and Illinois.
The clay-size material of the Iowa bentonites consists almost entirely
of randomly interstratified illite-montmorillonite, with a range of illite:
montmorillonite ratios from 4:1 to 7:3. Thus, they are similar to Ordovician
K-bentonites reported by others from eastern states. The mica polytype is
dioctahedral 1Md to 1M of low temperature origin. In
contrast, the predominant clay mineral in the normal marine limestones and
shales is well-crystallized, 2M1, dioctahedral illite.
The contacts between bentonites and limestones or shales are distinct; in a
few exposures a thin zone of finely laminated, reworked bentonite is
observed directly above the bentonite. The bentonites themselves are
unlaminated.
Accessory sand-size mineral grains from bentonites consist of euhedral
apatite, euhedral zircon, sanidine, pyrite, biotite and hornblende, whereas
those from shales are organic apatite, quartz and calcite. The bentonite
assemblage is suggestive of volcanic origin, and is similar to Ordovician
K-bentonites east of Iowa.
Differential thermal analysis reveals that the clay mineral of
bentonites altered at low temperatures through a montmorillonite stage and
became more micalike by K fixation. In contrast, DTA indicates that the
illite of shales originated as mica and is slightly weathered toward a
montmorillonitelike phase. Laboratory saturation of clays from adjacent
bentonites and shales with K+ demonstrates similar
relationships.
The usefulness of bentonites as key horizons for correlation within the
Ordovician is limited by several difficulties. Removal of ash by
contemporaneous reworking, the probable multiple centers of volcanic
activity in the Appalachian region and the great number of essentially
identical bentonites within a stratigraphic interval are major problems.
A Disordered Kaolinite from Concepcion de Buenos Aires, Jalisco,
Mexico
Authors: de Pablo Liberto 
Published: August 2006

Abstract
A random-layer disordered kaolinite from Conception
de Buenos Aires, Jalisco, Mexico, gives an X-ray diffraction pattern
resembling that of halloysite but has a kaolinite morphology. The mineral
was located in a lignite deposit and, apparently was formed by alteration of
volcanic rocks from the Cenozoic, with rapid cooling and sedimentation in
lacustrine deposits. It is associated with plagioclase, quartz,
cristobalite, montmorillonite, goethite and organic material. The analysis
of purified material (44.84 per cent SiO2, 40.36 per
cent Al2O3, 0.30 per cent
Fe2O3, 0.31 per cent CaO, and
13.99 per cent ignition loss) corresponds to the formula
(Si3·88 Al0·11
Fe0·01) (Al3·99
Fe0·01)O10
(OH)8. X-ray diffraction indicated a
d001 of 7.56 Å, an
intense 020, and displaced and nonsymmetrical reflections corresponding to a
bi- and tridimensional diffracting system closer to halloysite than to
kaolinite. Computed cell edges were a = 5.18 Å,
b = 8.97 Å, and c
= 7.45 Å. Electron micrographs showed anhedral rounded particles averaging
0.22 µ in size, while infrared absorption indicated some displacement in the
absorption bands. The relationships of the mineral to kaolinite, halloysite
and disordered kaolinites are discussed in terms of the 7°38′ twist of the
tetrahedra, the intensities of the reflections, and the calculated
AlIV substitution.
Swelling Properties of Synthetic Smectites in Relation to Lattice
Substitutions
Authors: Harward M. E. , Brindley G. W. 
Published: August 2006

Abstract
Synthetic clays were prepared hydrothermally at 300°
to 350°C and 15,000 psi from gels with compositions calculated to give a
series of octahedrally and tetrahedrally substituted, 2:1-type layer
silicates with charges of 0.5N, 1N, 1.5N, 2N, 2.5N, and 3N, where N equals
the “normal” layer charge of montmorillonite. Besides montmorillonites and
beidellites, the products also contained other components, kaolinite,
saponite, paragonite and possibly amorphous materials, depending on the
initial gel compositions. Cation exchange capacities of
<2µ fractions treated for removal of
amorphous constituents were within the narrow range of 0.95–1.35 meq per g
rather than 0.45–2.70 meq per g as calculated from initial gel
compositions.
Comparisons between the expanding properties of these materials showed
that the beidellites expanded less readily than the montmorillonites upon
solvation with glycerol vapor and tended to give single interlayer
complexes. These differences were most pronounced when Mg was the saturating
ion, although they were also apparent with Ca.
The K-saturated montmorillonites gave greater expansion than the
beidellites on hydration at 100 per cent r. h. The montmorillonites also
exhibited greater rehydration than the beidellites after heating at
400°–500°C.
Beidellite exhibits properties of expansion that are intermediate
between those of montmorillonite and vermiculite. The results of this
investigation are consistent with the existence of somewhat stronger ionic
attractions in the beidellites than in the montmorillonites. The source of
the charge thus has an effect upon the properties of expansion.
Structural Charge Density as Indicated by Montmorillonite
Hydration
Authors: Jonas Edward C. , Roberson Herman E. 
Published: August 2006

Abstract
A sodium-saturated Texas bentonite was fractionated
into six particle-size ranges. The expansion of each fraction was observed
by X-ray diffraction under controlled humidity conditions ranging from 0–100
per cent r.h. At all humidities, the fine fractions expanded more than the
coarse. A single size fraction expands through a series 10 Å, 12.4 Å and
15.5 Å. The expansion from 10–12.4 Å occurs at progressively lower relative
humidities for smaller size fractions in the same way as the expansion from
12.4–15.5 Å. The gradation from high resistance to expansion in the coarse
fractions to low resistance to expansion in the fine fractions appears to be
continuous.
Interlayer cation density, which controls the resistance to expansion,
is dependent upon the structural charge density on the silicate layer. The
continuous variation of resistance to expansion that is a function of
particle size is interpreted to indicate a corresponding continuous
variation in structural charge with particle size.
Lithium and Potassium Absorption, Differential Thermal, and Infrared
Properties of Some Montmorillonites
Authors: Schultz Leonard G. 
Published: August 2006

Abstract
Investigations are underway concerning
inter-relations of X-ray analyses of chemically treated samples, infrared
absorption and DTA for a group of 28 montmorillonite samples. Results to
date generally support Greene-Kelly’s LiCl test for evaluation of the
proportion of tetrahedral and octahedral layer charge in montmorillonite.
Decrease in expandable characteristics of the montmorillonites owing to
K+-saturation is much more closely related to the
total layer charge than to charge distribution in tetrahedral or octahedral
layers.
As the tetrahedral charge increases and the octahedral charge decreases,
the infrared absorption band at 11.95µ is replaced by one at 11.35–11.5µ,
and the absorption band at 9.2µ decreases or disappears.
Most DTA dehydroxylation peak temperatures are related to charge
distribution as follows:
Organoclays Bonded to Polyethylene by Ionizing Radiation
Authors: Nahin Paul G. 
Published: August 2006

Abstract
Exploratory experiments on irradiation of mixtures of
polyethylene and organo-montmorillonites with gamma rays indicated that the
polyethylene became crosslinked to the organoclays. Subsequently, 264
samples of 1:1 clay-polyethylene compositions were irradiated with 2 MeV
electrons and tested for tensile strength and weight fraction extractable in
toluene at 110°C. From statistical analysis of the variables of clay
lattice, clay surface, polyethylene type and radiation dose it is concluded
that: (1) polyethylene can be bonded directly to the clay surface by
ionizing radiation, and (2) at least one organoclay bearing a
“polyethylenelike” chain, polyvinyl alcohol, is more effective than wholly
inorganic clay for the purpose of radiatively linking polyethylene to clay
surface. The data below show the markedly increased solvent resistance of
polyethylene radiatively bonded to clay over that of equivalently irradiated
pure polyethylene.
Thermal Stability of Bentonites in Foundry Molding Sand
Authors: Vingas George J. , Zrimsek Arthur H. 
Published: August 2006

Abstract
The effects of heat on the behavior of sodium and
calcium bentonite in bonding foundry sands were studied.
Tests such as differential thermal analysis, viscosity, and melting or
vitrification temperatures do not indicate the suitability of a bentonite
for foundry use.
The deterioration temperatures of sodium and calcium bentonite are 1180°
and 600°F respectively.
Reactivities of bentonites with cereal as affected by temperature and
mulling were also studied. Flowability of sands, defined as mold
densification in this paper, is better with heated calcium than sodium
bentonite.
Heating bentonites alone does not simulate the conditions encountered in
heating bentonite-sand mixtures in a mold.
Particle Arrangements and Differential Imbibitional Swelling in Deformed
or Deposited Kaolinite-Illite Clay
Authors: Tressler Richard E. , Williamson William O. 
Published: August 2006

Abstract
A fine-grained kaolinite-illite clay, in which planar
particle orientation resulted from filtration or plastic deformation,
swelled differentially when liquid water was imbibed by test pieces already
in the plastic state. Swelling was greater perpendicular than parallel to
the plane in which the clay platelets tended to be arranged. Filtration, in
contrast to deformation, gave test pieces that swelled more rapidly and
extensively. The slipbands, present only in plastically deformed test
pieces, restricted the swelling. They were arranged diagonally to the plane
in which the clay platelets tended to lie. The plastically deformed test
pieces showed enhanced expansion perpendicular to this plane when they were
made successively thinner by compression under a cylindrical roller. This
was attributed to improved planar orientation of the clay
platelets.
New Amine Reagents for X-Ray Determination of Expandable Clays in Dry
Samples
Authors: Rex R. W. , Bauer W. R. 
Published: August 2006

Abstract
Quantitative X-ray diffraction analysis of minerals
can most readily be performed on dry powdered samples. Current methods for
determination of expandable clays require either wet oriented samples
treated with glycerine or glycol or dry, randomly oriented samples treated
with amines. Trimethylamine has been used to expand the montmorillonite
structure to a 13.3 Å basal spacing. Unfortunately, this spacing is subject
to considerable peak interferences.
We therefore undertook a review of amine-montmorillonite complexes for
more suitable reagents. The formate and acetate salts of tri-n-hexylamine
and of dimethyl-benzylamine meet our requirements. The peak positions are
the same as for glycerine complexes, while the physical properties are the
same as for trimethylamine.
Detailed studies of tri-n-hexylammoniura ion absorption suggest single
layers of ammonium ions lying parallel to the crystal basal plane, double
layers in similar orientation, and a single layer with molecules on end. The
most useful orientation is the latter, which occurs in the presence of an
excess of the ammonium salt and gives a montmorillonite spacing 18 Å in dry
powdered samples.
Linear calibration curves with a standard deviation of about 5 per cent
of the amount measured can be prepared using the conventional internal
standard techniques. Minimum detectable amount of montmorillonite with
rate-meter techniques is 0.4 per cent and 0.2 per cent with scalar
techniques.
Several thousand analyses using tri-n-hexylammonium ion have
demonstrated its effectiveness for expanding a wide variety of
sediments.
The Status of Clay Mineral Structures
Authors: Bailey S. W. 
Published: August 2006

AbstractThe basic outlines of most of the hydrous layer silicate structures were determined during the 1930’s. Present escalating interest in obtaining additional detail is indicated by (a) publication of over twenty structural refinements (2-D or 3-D) during 1954-64, (b) publication of at least nine structures in 1965 or early 1966, and (c) personal communication that at least fifteen additional refinements are in progress. Points of especial interest in these recent studies follow.1.Octahedral cation order is common, but tetrahedral cation order is confirmed in only three cases. Because ordering of Si, Al does not significantly affect the statistical tests for centrosymmetry, centrosymmetric space groups that do not permit order should be avoided during refinement.2.Oversize tetrahedral sheets articulate with smaller octahedral sheets by tetrahedral rotation and, for dioctahedral species, by tetrahedral tilting around vacant octahedra. The latter mechanism influences the type and regularity of layer sequences. Undersize tetrahedral sheets articulate with larger octahedral sheets by tilting plus octahedral contraction or by inversion of some tetrahedra.3.The amount and direction of tetrahedral rotation and tilt, length of T—O, M—O, and O—O bonds, sheet thicknesses, and relation of cell dimensions to composition can now be predicted with some confidence.4.Variation in layer stacking (polytypism) is common. In some cases the stabilities of different polytypes can be explained by the relative amounts of repulsion and attraction between the ions in the structures. The stabilities can be correlated with the energy available in the environment of crystallization.
Layer Charge Relations in Clay Minerals of Micaceous Soils and Sediments
Authors: Raman K. V. , Jackson M. L. 
Published: August 2006

AbstractMicaceous clays (“illites”) of a number of sediments, subjected to quantitative mineralogical analysis, ranged in different samples from 58 to 65% of a dioctahedral mica of muscovite type, from 3 to 8% vermiculite, from 0 to 10% montmorillonite, from 2 to 12% quartz, from 0 to 4% feldspars, from 1 to 2% rutile and anatase, from 0.3 to 1.2% free iron oxides, and from 16 to 30% chlorite. The soil clays contained less mica (13 to 35%) but more vermiculite (13 to 16%), montmorillonite (6 to 14%) and chlorite (30 to 33%), besides kaolinite (3 to 8%) and amorphous material (6 to 15%). The presence of the various minerals was verified by X-ray diffraction. When the interlayer K of these micaceous clays was replaced by hydrated Na ions through treatment with 0.2 n sodium tetraphenylboron in 1 n NaCl, the analytically determined vermiculite and montmorillonite contents increased. The freshly produced vermiculites had an interlayer charge of 177 to 198 me/100 g. During this replacement of interlayer K in a 1 N salt solution, the pH of the equilibrium matrix solution was observed to increase instead of decreasing as would be expected if oxonium (OH3+) ions were associated with K in the interlayer space, thus precluding the possibility of interlayer ONz+. The calculated stoichiometric equivalent of the pH rise established a significant uptake of protons by the lattice as K was released.Thermal analyses of vermiculites show 0.5 to 0.7% higher OH water content than the parent micas. Oxidation of ferrous iron in the silicate structure, suggested as a possible mechanism for lowering of layer charge during weathering of mica to vermiculite, accounted for about 66% of this in samples high in iron (16.0% FeO) and only 30% of this in samples fairly low in iron. The rate of extraction of K from muscovite with no ferrous iron was found to be pH dependent, increasing at lower pH values. The data indicate proton incorporation with structural oxygens of the silicate sheet to form OH as a charge reduction mechanism in weathering of mica, independent of and additional to that involving the oxidation of ferrous iron.
Susceptibility of Interlayer Potassium in Micas to Exchange with Sodium
Authors: Scott A. D. , Smith S. J. 
Published: August 2006

AbstractInterlayer K in muscovite, biotite, phlogopite, illite and vermiculite-hydrobiotite samples was replaced by cation exchange with Na. The rate and amount of exchange varied with the mineral and the level of K in solution.Essentially, all the K in muscovite, biotite, phlogopite and vermiculite was exchangeable when the mass-action effect of the replaced KT was reduced by maintaining a very low level of K in solution. The time required for this exchange varied from < 10 hr with vermiculite to > 45 weeks with muscovite. Only 66% of the K in the illite was exchangeable under these conditions. When the replaced K was allowed to accumulate in the solution, the amount of exchange was determined by the level of K in solution required for equilibrium. These levels decreased with the degree of K-depletion and with the selectivity of the mica for K. The order of selectivity was muscovite > illite > biotite > phlogopite > vermiculite. Decreasing the K in solution from 10 to 7 ppm increased the exchangeable K in biotite from 30 to 100%. A K level of only 0.1 ppm restricted the exchange of K in muscovite to 17%.A decrease in layer charge was not required for K exchange, but a decrease did occur in K-depleted biotite and vermiculite. Muscovite with the highest layer charge (247 meq/100 g), least expansion with Na (12.3Å), and least sensitivity to solution pH had the highest selectivity for K and the slowest rate of exchange. The K in vermiculite was the most readily exchangeable.
Mechanical Force Fields in a Clay Mineral Particle System
Authors: Geuze E. C. W. A. , Rebull Peter M. 
Published: August 2006

AbstractElectrical double layer theory is used to analyze an idealized model unit of a clay particle system with the purpose of describing the mechanical stability in terms of an equilibrium of attractive and repulsive forces. Restricting the analysis to two dimensions, a symmetrical parallelogram formed by four typical clay mineral particles is taken as a representative unit of a flocculated clay and the interactions of mineral faces and associated electrolyte is investigated. The distortion energy of the system thus found is then directly related to the mechanical stability of the model unit’s structure as it varies from parallel to perpendicular orientation. The general pattern of behaviour of the model unit will be shown to be compatible with the mechanical behavior of the clay mass.
Equilibrium Theory of the Kaolinite-Water System at Low Moisture Contents, with Some Remarks Concerning Adsorption Hysteresis
Authors: Sposito Garrison , Babcock K. L. 
Published: August 2006

AbstractA microscopic theory of the kaolinite-water system is presented, based upon the assumption that the clay-water interaction may be envisioned as partly hydration of the exchangeable cations and partly adsorption by the oxygen and hydroxyl surfaces. The theory treats exchangeable cation hydration quantum-mechanically as an ion-dipole phenomenon and considers water adsorption by the mineral surface as a problem in hydrogen bonding. A statistical mechanical model incorporating the quantum-theoretical results is then invoked to find the contribution of each component interaction to the initial portion of the adsorption isotherm for homoionic kaolinite. Good agreement between the theoretical calculations and available experimental data is achieved for water vapor adsorption by Li-, Na-, K-, and Mg-kaolinite, without the use of ad hoc empirical parameters. The concordance, in turn, is used to suggest that the basis for adsorption hysteresis in kaolinite-water vapor systems is the irreversible transition: mineral surface water → cation hydration water.
Kinetics of Decomposition of Cobalt Coordination Complexes on Montmorillonite Surfaces
Authors: Fripiat J. J. , Helsen J. 
Published: August 2006

AbstractMontmorillonite may adsorb cobalt(III)hexammine and cobalt(III)chloropentammine cations, and the C.E.C. determined for these complex cations is of the order of magnitude of that obtained with ammonium. The infrared spectra of these coordination complexes adsorbed by the clay are similar to those observed for the corresponding chloride salts. However, when montmorillonite treated with these coordination complexes is dehydrated in vacuum or under moderate temperature conditions (<100°C) in a dry atmosphere, the infrared spectra are deeply modified. The complex cations decompose with NH3 evolution and ammonium formation. Cobalt(II)hydroxide is produced and ammonium cations balance the lattice electrical charge. The true decomposition rate was followed by IR absorbance of NH4 which showed that the complex decomposition followed that for the nomothetic decomposition of solid particles. The apparent activation energy of the decomposition was 20.5 and 43 kcal/mole for the CoCl(NH3)52+- and Co(NH3)68+-montmorillonite complexes respectively. An analysis of the combined chemical and IR data on the hexammine complex permitted calculation of the NH3 diffusion rate between collapsed montmorillonite sheets. When the interplanar gap approaches 1Å the diffusion coefficient is approximately 7 × 10-19 cm2/sec. In contradiction to their stability in solutions, the cobalt(III)hexammine cation is less stable than the cobalt(III)chloropentammine cation when absorbed on montmorillonite.
Infrared Study of the Thermal Decomposition of Ammonium Rectorite
Authors: Russell J. D. , White J. L. 
Published: August 2006

AbstractChanges in the infrared absorption spectrum of ammonium-saturated rectorite on heating suggest that the ammonium cations are hydrogen bonded to water molecules when the mineral is hydrated. Further spectral changes above 300°C indicate that lattice OH groups are perturbed by protons liberated from the decomposition of ammonium ions giving rise to an absorption doublet at 3500 and 3476 cm-1. The doublet attains maximal intensity when decomposition of ammonium cations and dehydroxylation of the mineral is complete at about 550°C.The perturbation effect occurs only for swelling dioctahedral minerals which derive their layer charge from Al-for-Si substitution.
Alteration and Formation of Clay Minerals During Cat Clay Development
Authors: Lynn Warren C. , Whittig Lynn D. 
Published: August 2006

AbstractThe natural tidelands sediments along the north shore of San Pablo Bay, California, are neutral in reaction and subjected to a wet, reducing environment conducive to ferrous sulfide accumulation. When the sediments are diked and drained, the environment rapidly becomes oxidizing and generally dry. Oxidation of the ferrous sulfide results in extremely acid cat clays within a year or two.Undrained sediments from the area contain montmorillonite, chlorite, mica, and kaolinite that all give sharp X-ray diffraction patterns. Sediments drained for 6 years, although strongly acid, have virtually the same clay mineralogy as the undrained sediments. However, sediments drained for 60 years show a general deterioration of crystalline clay minerals, particularly chlorite. The deterioration decreases with depth until the deeper zones closely resemble the undrained sediments.In separate laboratory experiments, chlorites were formed in an oxidized soil that was subjected to reducing conditions simulating the environment of the undrained tidelands sediments. The possibility exists, therefore, that chlorites in the undrained sediments may have formed subsequent to deposition.