bluuebunny/crossref_metadata_2025_split huggingface dataset:
Petrographic Study of Clay Materials
Authors: Grim Ralph E. 
Published: August 2006

Abstract
Some investigntors have used petrographic methods as the sole means of
making clay mineral analyses, whereas others have considered petrographie
metliods to be useless for materials as fine grained as clays. The value of
the method lies between these extremes. It has consideralde value, but it
has limitations and must be used with cantion.
By the use of varions auxiliary techniques it is usually possible to
obtain fairly precise values for the indices of refraction and birefringence
of the clay mineral components of a clay material. Frequently an
interference figure can be obtained which yields farther data on the optical
characteristics. The presence of very fine non-clay minerals, such as quartz
and carbonate, and organic material and iron oxide or hydroxide may prevent
the making of satisfactory optical measurements.
It is necessary to decide if the optical data obtained arc influenced by
contamination with nonclay minerals, and if they indicate a single clay
mineral or mixture of clay minerals. Fortunately the optical values
themselves and the character of the particles on which they were determined
give good clues regarding purity and monomineral characteristics.
Optical data in general will not permit the detection of relatively
small amounts of a clay mineral in a clay mineral mixture. Also such data
may l)e very misleading in studies of mixed-layer clay minerals.
In addition to optical data, petrographic studies of clay materials
yield other important information. They are of value in determining the
texture of the rock and the relative abundance and size of the nonclay
minerals. In general microscopic studies are easy to perform and the
probable value from them is so great, that they should be made in all clay
material researches.
Physical-Chemical Properties and Engineering Performance of Clays
Authors: Mielenz Richard C. , King Myrle E. 
Published: August 2006

Abstract
Fabric (texture and structure) and minpralogic composition determine the
response of clays and shales to events occurrins during construction and
operation of engineering works. A new system of classification of the fabric
of earth materials is proposed. Characteristic minpralogic composition of
clays and shales, especially in the western United States, is described.
Fabric and composition are correlated with soil mechanics properties and
engineering performance. Needed research on clays and shales as a basis for
design, construction, and maintenance of engineering structures is
emphasized.
The Origin of Missouri Fire Clays
Authors: Keller W. D. , Westcott James F. , Bledsoe A. O. 
Published: August 2006

AbstractThe origin of Missouri fire clays is interpreted from the testimony of the clays in terms of the geologic setting in which they were deposited and developed. Hence, the approach to the interpretation is fundamentally that of sedimentary petrology, rather than economic geology. The clays, as sedimentary rocks, are considered to be the products (mineralogic and geologic) resulting from the responses of their source materials to the energetics of the physical and chemical environments which were impressed upon them during the time interval of their deposition and diagenesis.The fire clays are inferred to have a sedimentary origin; it is believed that their present-day characteristics were essentially developed in the time intervals of the Cheltenham to pre-Fort Scott (Pennsylvanian) age. The different varieties of fire clay are interpreted as different lithofacies within a continuous Cheltenham deposit. The high-alumina facies (diaspore-burley and boehmite) appears to have been formed by severe leaching on a relatively stable land area, whereas the kaolinitic-illitic facies (semi-plastic to semi-flint clay) seem to characterize products formed near the margin of a slowly sinking depositional region. Both processes of destruction and construction (“katamorphism” and “anamorphism,” as used by Van Hise, 1904) appear to have operated in the genesis of the clay minerals.Evidence points toward a negative Eh and an approximately neutral to slightly acid pH during the formation of the clays. The presence of diaspore and boehmite and the absence of gibbsite in the high-alumina clay are interpreted as indications of leaching of clay minerals under waterlogged conditions. Diaspore may inherit part of the crystal structure and energy of the kaolinite from which it was derived.
Hydrated Halloysite in Blue Hill Shale
Authors: Swineford Ada , McNeal John D. , Crumpton Carl F. 
Published: August 2006

AbstractNodules of alunite and hydrated halloysite occur in the upper part of the Cretaceous Blue Hill shale at three localities in west-central Kansas. They have formed at the contact of septarian concretions with the shale and are associated with gypsum. The nodules are judged to have been formed by the action of sulfuric acid from pyrite on the potassium-bearing minerals of the Blue Hill shale, perhaps under special conditions of pH and Eh produced locally by the presence of septaria.The minerals were studied and identified by x-ray diffraction, thermal data, chemical analysis, and electron and light microscopy.
Clay Minerals in a Limestone Soil Profile
Authors: Carroll Dorothy , Hathaway John C. 
Published: August 2006

AbstractThe clay minerals in a soil developed from Lenoir limestone (Ordovician) in Augusta County, Va., are kaolinite and chlorite. The Lenoir limestone contains clay partings consisting of hydrous mica, and the clay in the soil is considered to be residual from that in the parent limestone and modified by soil-forming processes (podzolic). X-ray diffraction patterns of the clay fraction (<2μ) from samples from different positions in the profile show a reduction in hydrous mica and an increase in kaolinite and chlorite content as the A horizon is reached. Partial chemical analyses of the whole soil and of the clay fractions are given, as well as pH and ion-exchange capacity determinations. The silica-alumina ratios are similar to those characteristic of podzolic soils, and excess silica in the A horizon accumulates as recrystallized quartz together with chert which is considered to be residual from the limestone. Mechanical analyses by the standard pipette method show that the quantity of clay in the soil varies from 17 percent at the surface to 61 percent at 26 inches (C horizon).
Preliminary Study of the Effects of Water Vapor Pressure on Thermograms of Kaolinitic Soils
Authors: Stone Robert L. 
Published: August 2006

AbstractKaolinites found in soils generally give poorer thermograms than commercial kaolins. When run under dynamic steam atmospheres up to 90 psi, the endothermic peaks are sharpened and moved upward; the exotherm is made less intense and moved downward. Because of the effects observed, the method promises to be of interest in theoretical studies of hydrates and hydroxides.
X-Ray Diffraction Criteria for the Characterization of Chloritic Material in Sediments
Authors: Bradley W. F. 
Published: August 2006

AbstractRecent surveys of clay mineral assemblages in argillaceous sediments have indicated that chloritic minerals are of more frequent occurrence and of greater significance than was formerly recognized.The wide latitude of compositional variations within the chlorite crystallization scheme introduces enough complexity into the x-ray diffraction identification and characterization of these minerals that a detailed description of a few typical clay mineral associations seems justified.For the simplest cases, in which resolution of diffraction features from entirely chloritic grains can actually be demonstrated, analyses may be highly reliable. Further, for many unresolved instances, simple heat treatments effect reliable identifications.For more complicated assemblages, in which coherently scattering domains are mixtures within themselves, individually planned heating or swelling reactions may become necessary.Typical natural examples are illustrated, for which apparently proper distinctions have been made for characterizing associations on mono- and mixed-clay mineral grains.
New Data on the Composition and Identification of Chlorites
Authors: Nelson Bruce W. , Roy Rustum 
Published: August 2006

AbstractA series of clay minerals with a 7A series of reflections has been shown to exist in the MgO-Al2O3-SiO2-H2O system. It has been demonstrated both on synthetic and natural samples that these minerals are polymorphous with the 14A-series chlorite minerals. Widespread occurrence of these minerals in nature is expected. The polymorphic relationship found clarifies the whole picture of the isomorphism of the chlorites. The problem of nomenclature of these 7 A series minerals is examined and the term “septechlorites” hesitantly proposed.On the basis of some experimental work it is shown that the currently adopted procedure for the identification of chlorites is not generally valid, and that the factors of time, temperature, composition and particle size are of crucial importance in such procedures.
The Relation Between “Illite,” Beidellite, and Montmorillonite
Authors: Foster Margaret D. 
Published: August 2006

AbstractFormulas calculated from analyses, written in the fractional notation used by Ross and Hendricks, and with a notation of tetrahedral and octahedral charge, reveal relationships between the hydrous micas called “illite,” montmorillonites (using the term in the restricted sense), and beidellites not otherwise apparent. These relationships are shown graphically by means of histograms made up of five columns, representing respectively, total charge, tetrahedral charge, octahedral charge, potassium, and water.“Illites” have a much higher total charge and a much higher tetrahedral charge than montmorillonites, of which the tetrahedral charge is usually insignificant. Consequently simple removal of fixed K and its replacement by exchangeable cations would not convert an “illite” to a montmorillonite nor would mere fixation of K between the layers of a montmorillonite result in the formation of an “illite” like any that have been described.From the standpoint of octahedral-tetrahedral charge relationships, beidellites and “illites” should be more similar than montmorillonites and “illites.” However, considerable doubt has been cast by Grim and Rowland on the purity of most of the materials that have been called beidellites; they interpreted the differential thermal curves of the beidellites examined by them as indicating mixtures of kaolinite or halloy-site, “illite,” and montmorillonite. Formulas based on calculated mixtures of these minerals in varying proportions were very similar to formulas calculated from analyses of the so-called beidellites. Thus the existence of a montmorillonite clay like that which would be formed if the fixed K in “illite” were removed and replaced by exchangeable cations has not been authenticated and the concept that montmorillonite and “illite” are analogous except for the presence or absence of nonexchangeable potassium is misleading and is an oversimplification of the relationship between the two groups of minerals.
The Thermodynamics of Ion Exchange on Clay Minerals. A Preliminary Report on the System Montmorillonite-Cs-Sr
Authors: Thomas Henry C. , Gaines George L. 
Published: August 2006

AbstractA discussion is given of the advantages of the thermodynamic approach in the study of clay-ion-water systems. Generally valid equations for the description of the systems are given, and the relative significance of the osmotic terms is roughly assessed. The principal theoretical and experimental problem is the determination of the initial slopes of the exchange isotherms, and a formal method for handling this difficulty is described. Preliminary results on the system montmorillonite-cesium-strontium are used for illustrative purposes.
Colloid Science of Montmorillonites and Bentonites
Authors: Hauser Ernst A. , Colombo Umberto 
Published: August 2006

AbstractIn 1847 the name “montmorillonite” was given to a rose-red, clay-like mineral forming nests in a brown clay at Montmorillon, France. The first analysis, reported by Salvetat, gave 49.4 percent to SiO2, 19.7 percent to Al2O3, 0.8 percent to Fe2O3, 0.27 percent to MgO, 1.5 percent to CaO, 1.5 percent to alkalies, and 25.67 percent to H2O. Much later a substance which was originally called “taylorite” after William Taylor, who was the first to draw attention to it, was finally designated as “bentonite” because it was first found in the Fort Benton series of rocks in Montana. The most characteristic mineral component of bentonite is crystalline and definitely montmorillonite.The chemical analyses of Wyoming bentonite and hectorite are compared with those of three different calcium bentonite deposits. The importance of more up-to-date crystal chemical considerations is discussed. The electrophoretic properties of bentonites are explained on the basis of the available counter ions. The formation of thixotropic bentonite gels is discussed in detail and proof is offered to show why calcium bentonites do not give thixotropic systems.The base-exchange capacities of sodium-bentonites and of calcium-bentonites and their differences are explained on the basis of two different methods of determining this phenomenon.Ultra- and electron photomicrographic studies reveal the difference between montmorillonites and the various types of bentonites now known. Most striking is the fact that most bentonites, specifically calcium bentonites, contain several different types of clayey minerals.The most probable cause of the formation of bentonitic clays as well as of true montmorillonite is referred to and discussed.
Mathematical Analysis of a Layer Extraction Method for Separating Clay-Size Material from Soils
Authors: Chu T. Y. , Davidson D. T. , Sheeler J. B. 
Published: August 2006

AbstractThis paper presents a layer extraction method for obtaining a representative sample of clay-size material from a soil suspension. This method is especially advantageous in preparing a sample of relatively large size, and the procedure is simpler than that of the decantation method, a comparable method of extraction.In the layer method, the position and the thickness of the layer to be extracted from a soil suspension can be varied and one or more extractions can be made. The effect of these variables on the size composition and the quantity of the extracted material is analyzed mathematically. Based upon such an analysis, the proper position and thickness of the layer and the desirable number of extractions can be determined to suit the requirements of a particular test.
The Mechanism of the Deformation of Clay
Authors: Buessem W. R. , Nagy Bartholomew 
Published: August 2006

AbstractKaolinite-water mixtures, containing from 23 percent to 33 percent water, were subjected to compression plastometer tests and their plasticity was studied by means of the calculated strain-stress functions. X-ray diagrams taken of the compressed samples showed that an oriented texture developed during the compression, i.e., the basal planes of the flaky clay particles were arranged parallel to a plane normal to the direction of the applied stress. For the purpose of discussion the concept of the “plastic unit cell” is introduced. The “plastic unit cell” is a cubic volume element, the faces of which are perpendicular to the three principal stresses. The size of the “plastic unit cell” is very small as compared with the size of the macroscopic sample but large as compared with the size of one clay particle. It is the smallest unit for all considerations where macroscopic strain and stress distributions are involved. For all considerations involving the correlation between the characteristic strain-stress function of the material, the motions of the clay particles and water, and the forces present between the particles, the “plastic unit cell” is the largest unit.The clay particle in itself is rigid and, therefore, it cannot undergo the same deformation as does the “plastic unit cell”. All of the clay particles present in a “plastic unit cell” together can go through a series of motions (translations and rotations) which, in effect, simulate the deformation of the “plastic unit cell”. In the case of the compression test, the translatory and rotatory movements of the clay particles lead to the development of the oriented texture.
Weathering According to the Cationic Bonding Energies of Colloids
Authors: Graham E. R. 
Published: August 2006

AbstractA study was made of the energy changes of several colloidal systems in relation to weathering.The total energy change associated with pH, total hydrogen, and bonding energy involved in the weathering of natural phosphates was established by mixing particles of apatite with hydrogen systems of amberlite (I.R. 120), bentonite clay, Putnam clay, kaolinite, and humus. Mixtures of potassium-saturated bentonite, sodium-saturated bentonite, and powdered rock phosphate were also investigated for weathering changes.The amount of phosphorus weathered was related to hydrogen bonding at the outset and to calcium bonding energy of the colloidal system. H-amberlite, which has the highest bonding energy for calcium of the systems studied, was most effective in weathering phosphate minerals. H-humus, which has the lowest bonding energy for calcium was least effective as a weathering agent. The clay minerals weathered according to the relative energy levels resulting from the consideration of both hydrogen and calcium bonding energies. Bentonite clay was the most effective weathering agent; Putnam clay intermediate, and kaolinite the least effective. Bentonite clay saturated with potassium or sodium was effective as a phosphate mineral weathering agent.
A Study in Morphology by Electron Diffraction
Authors: Sand L. B. , Comer J. J. 
Published: August 2006

AbstractA stabilized halloysite-glycerol complex was studied by electron microscope and electron diffraction techniques. The basal reflection was found to be 10.7 Å by both electron diffraction and X-ray diffraction analyses. Electron micrographs of the expanded lattice (halloysite-glycerol complex) were not different from those of the collapsed lattice (halloysite). On the basis of the tubes evident in the micrographs and the fact that the basal reflection was present in the transmission electron diffraction pattern, it was established that the halloysite-glycerol complex is tubular. Since this complex has an expanded lattice 0.6 Å greater than hydrated halloysite, it is believed that hydrated halloysite (endellite) is tubular as postulated by Bates, Hildebrand and Swineford.
The Reversible Dehydroxylization of Clay Minerals
Authors: Jonas Edward C. 
Published: August 2006

AbstractRehydroxylization of the anhydrous modification of dioctahedral montmorillonites can be carried out under DTA conditions with controlled atmosphere techniques. The structural character of the rehydrate prepared in this way is determined from X-ray and DTA data. The mechanism of the reactions by which the rehydrate can be formed is also considered. Thermal analysis curves of the rehydrate form of several pure mont-morillonite samples failed to show any large variation such as is shown by the curves of the original clays themselves. The possibility is considered that such large variations in the dehydroxylization curves of montmorillonites are related to structural instead of compositional variations within the sample. It is suggested that montmorillonites showing two reactions attributable to dehydroxylization may be mixtures of the rehydrate form and montmorillonite.
Anomalies in the Ethylene Glycol Solvation Technique Used in X-Ray Diffraction
Authors: Kunze G. W. 
Published: August 2006

AbstractX-ray diffraction results are presented to show that some montmorillonites will not retain two layers of ethylene glycol in the interlayer space when dried under atmospheric conditions. Diffraction data obtained from such samples of montmorillonite may erroneously be attributed to mixed layer minerals. Studies have shown however that this difficulty may largely be overcome by initially saturating the sample with ethylene glycol by the vaporization technique described, after which the sample is placed in a saturated atmosphere of ethylene glycol for a period of 12–24 hours to come to equilibrium and then irradiated.
Swelling of Clay under Pressure
Authors: Nahin Paul G. 
Published: August 2006

AbstractAn experimental technique for studying the swelling of clay under constraint and some preliminary results for the swelling of Wyoming bentonite in several media are presented and discussed. Fractionated, powdered clay is mixed with an equal weight of non-swelling microporous porcelain, which serves to distribute the swelling agent rapidly and uniformly. The mix is compacted in a cell at high pressure and permitted to imbibe fluid through a porous porcelain plate under simultaneously applied almost equal pressures from 0 to 10,000 psig on both sides of the fluid-gel interface. The unidirectionally constrained volume change of the sample is measured by displacement of mercury in a steel buret. Degree of swelling is taken as the volume ratio of gel to 105° C dry clay.In the range of pressure from 0 to 10,000 psig, the colloidal magnesium sodium montmorillonite swells from about 93 to 231 percent (volume ratio 1.93 to 3.31) depending on the composition of imbibed fluid. Aqueous 0.171N sodium chloride and magnesium chloride solutions produce 14 and 11 percent, respectively, more swelling at 1,500 than at 0 psig. Swelling in calcium chloride solution is insensitive to this pressure change. At 10,000 psig these solutions, and hydrochloric acid, produce less swelling than at 1,500 psig and, in fact, produce almost equal swellings of 130± 4 percent. It is inferred that swelling in chloride solutions at this pressure may be essentially cation-independent. Within the concentration range of 0 to 171N there appears to be little practical difference in the degree of swelling of the clay by sodium chloride and calcium chloride solutions; the swelling is a linear function of the logarithm of the salt concentration.Comparison of d(001) spacings calculated from swelling ratios with those obtained by X-ray diffraction lead to the conclusion that the method measures crystalline swelling in contradistinction to osmotic swelling.