bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clay Minerals of the Outcropping Basal Cretaceous Beds Between the Cape Fear River, North Carolina, and Lynches River, South Carolina
Authors: Heron S. Duncan 
Published: August 2006

AbstractThe basal Cretaceous beds of the area are subdivided into three units: the Cape Fear formation, Middendorf formation and Bladen member of the Black Creek formation. Stratigraphic position and lithology indicate that the Cape Fear is the oldest and the Middendorf is in part the landward facies of the Bladen. The Middendorf sediments are fluviatile and the Cape Fear and Bladen sediments are probably marine.The Cape Fear and Bladen contain abundant montmorillonite, some kaolinite and lesser amounts of illite. In the Middendorf kaolinite predominates, although a few samples have small amounts of montmorillonite and illite.Preliminary data indicate that in the Cretaceous-Tertiary sediments of the Atlantic Coastal Plain, montmorillonite occurs in abundance in the marine beds and kaolinite in the nonmarine sediments. The basal Cretaceous beds of the area studied fit into this scheme of clay mineral distribution.The origin of the clay minerals of the Cretaceous formations studied is approached from sedimentary and empirical standpoints. The montmorillonite-marine and kaolinite-nonmarine associations strongly suggest that the montmorillonite has formed by marine diegenesis, whereas the sedimentary evidence suggests that the montmorillonite of the Cape Fear formation is detrital and the kaolinite of the Middendorf formation has formed by prolonged postdepositional weathering of a more varied clay mineral assemblage. The sediments of the Bladen unit in themselves offer little evidence as to the origin of their clay minerals. However, the predominance of kaolinite in the contemporary deltaic Bladen suggest that kaolinite was the only clay mineral supplied to the depositional area, and that in the marine part of the sedimentation area part of this kaolinite was changed to montmorillonite by marine diagnetic processes.
X-Ray and Infrared Data on Hectorite-Guanidines and Montmorillonite-Guanidines
Authors: Beck Carl W. , Brunton George 
Published: August 2006

AbstractClay-organic complexes of the clay minerals sodium hectorite and sodium montmorillonite with the hydrochlorides of guanidine, amino-guanidine, methylguanidine, and triamino-guanidine were examined for thermal stability by the oscillating-heating x-ray technique. Completely exchanged complexes increase the thermal stability of these two clays by as much as 275°C.Infrared analyses were also made on these same clay-organic complexes. There is a marked difference between the infrared patterns of the clay—organic complexes and the patterns of the clays or the organic salts alone. More experimental work must be done before it will be possible to interpret completely the clay-organic infrared patterns.
Chemical Weathering of Layer Silicate Clays in Loess-Derived Tama Silt Loam of Southwestern Wisconsin
Authors: Glenn R. C. , Jackson M. L. , Hole F. D. , Lee G. B. 
Published: August 2006

AbstractChemical weathering of layer silicate clay minerals in the major horizons of the Tama silt loam Prairie soil profile was followed down to 10 ft, where the calcareous parent loess was encountered, and on down to a depth of 13 ft. The predominant constituents of the clay fraction (- 2 μ) at all depths in the soil profile were montmorillonite (42 percent) and illite (20 percent), although vermiculite (12 percent), kaolinite (5 percent) and amorphous material (15 percent) were also in fair abundance. Deposition of secondary inter-layer alumina was appreciable in the uppermost soil horizons but became less in amount in the deeper soil horizons. Quartz was not found in the clay fractions of less than 0.2 μ in diameter at any depth in the soil profile, although both quartz and feldspars occurred in the coarse clay.Vermiculite decreased from about 18 percent in the coarse clay and 5 percent in the fine clay of the deeper calcareous horizons to small amounts toward the soil surface, disappearing altogether in the fine clay ( - 0.08 μ). Little variation was found in the montmorillonite percentage of the clay in the subsoil and lower horizons (64 to 75 percent of the fine clay), but a decrease in the 18Å diffraction intensity of montmorillonite concurrent with an increase in amorphous silica and alumina (15 to 27 percent of the fine clay) was observed in the upper, acid, soil horizons, suggesting that montmorillonite is not a stable weathering product in the latter. Elemental analyses of the fine clays showed about 1.1 out of 4 octahedral positions to be Fe, 2.5 to be Al, and 0.4 to be Mg. A slight decrease in Fe and increase in Al in the montmorillonite octahedral structure occurred progressively in approaching the more intensely weathered zones near the soil surface.The results suggest that dioctahedral montmorillonite has formed to considerable extent in both the calcareous and noncalcareous horizons by chemical weathering of tri-octahedral ferromagnesian mica, through a vermiculite intermediate stage. The decrease in amount of the silt fractions of density greater than 2.66 g/cm3 (found to be composed mainly of biotite, chlorite, and amphiboles) in going from the calcareous horizons toward the soil surface approximately equalled the increase in montmorillonite percentage of the soil, suggesting that montmorillonite of the loess originated by chemical weathering of the ferromagnesian minerals of the silt. The genesis of the loessial montmorillonite begins long before the free CaCO3 has been leached out (6 percent montmorillonite in the loess at 13 ft) and continues to a maximum (14 percent) in the B horizon. Some eluviation of montmorillonite from the A horizon into the B horizon was evident.
A Study of the Synhesis of Hectorite
Authors: Granquist W. T. , Pollack S. S. 
Published: August 2006

AbstractHectorite, a trioctahedral magnesium montmorillonite, has been synthesized at atmospheric pressure and reflux temperature. The reaction mixture was the system SiO2/MgO/Li2O (or LiF)/Na2O in a large excess of water. The starting ratios were based on the following formula for the mineral [(LixMg6−x)Si8O20(OH)4]x−.xNa+.${\left[ {\left( {L{i_x}M{g_6}_{ - x}} \right)S{i_8}{O_{20}}{{\left( {OH} \right)}_4}} \right]^{x - }}^.xN{a^ + }.$Li+ has been found to accelerate the crystallization, and reasons for this effect are considered. Lowering of the pH of the reaction mixture by the use of alkali metal fluorides rather than hydroxides, resulting in an increase in the solubility of Mg(OH)2, also caused the crystallization of hectorite to proceed more rapidly. The products containing Li+ and F− proxying for Mg2+ and OH−, respectively, were found to be most like natural hectorite.The time-dependent data obtained in this work were rationalized on the basis of a postulated appearance of hectorite embryos in the dilute aqueous solution of Mg2+, OH− and SiO2, followed by growth of this material to crystalline hectorite by transfer of components from solution to the solid phase.Strese and Hofmann (1941) also conducted synthesis work in this area. A comparison of the products resulting from the two techniques showed the main difference to be the presence of 00l spacings in the current product. These earlier workers made a point of the lack of 00l reflections.
A Mixed-Layer Clay Mineral Associated with an Evaporite
Authors: Grim R. E. , Droste John B. , Bradley W. F. 
Published: August 2006

AbstractClay partings in the ore beds in a New Mexico evaporite section include a range of mixed-layer clay mineral sequences of the corrensite type. Specimens range from nearly regular alternations to sequences which depart from regularity to moderate degrees. The ore bodies consist of halite, polyhalite, sylvite, magnesite, dolomite, carnallite, and iron oxides.Observed x-ray diffraction effects from representative specimens are compared with synthesized effects for montmorillonite- or vermiculite-chlorite layer sequences.It is concluded that the segregation of the abundant Mg interlayer content into specific, regularly spaced interlayers represents the equilibrium relationship between a montmorillonite-chlorite or vermiculite-chlorite mixed assemblage and a mildly acid, Mg2+-, Na+- and K+-rich environment.
Hydraulic Flow Through Saturated Clays
Authors: Olsen Harold W. 
Published: August 2006

AbstractThe factors. (1) possible violations of Darcy’s law. (2) electrokinetic coupling. (3) high viscosity. (4) tortuous flow paths, an. (5) unequal pore sizes have been suggested as possible explanations for the differences between hydraulic flow rates in liquid-saturated clays and sands. The effects of these factors on hydraulic flow rates through saturated clays were investigated.Hydraulic flow rates, electrical conductivities, and streaming potentials were measured on natural, sodium, and calcium samples of kaolinite, illite and Boston blue clay. Data were taken after increments of one-dimensional consolidation and rebound over the pressure range from one-sixteenth to 256 atm.The influences of electrokinetic coupling on the hydraulic flow rates were calculated from irreversible thermodynamic relationships together with the hydraulic and electrical data. The other factors were studied by examining the extent to which each factor explains the discrepancies between measured flow rates and those predicted from Darcy’s law and the Kozeny-Carman equation.The results show that. (1) the possible violations of Darcy’s law and electrokinetic coupling are insignificant. (2) high viscosity and/or tortuous flow paths fail completely to account for the discrepancies between measured and predicted flow rates in clays, an. (3) unequal pore sizes can explain all the discrepancies.
Shear Strength and Consolidation Characteristics of Calcium and Magnesium Illite
Authors: Olson Roy E. , Mitronovas Frederick 
Published: August 2006

AbstractIn recent soil mechanics literature attempts have been made to explain the engineering properties of clays in terms of surface chemical theories, particularly the Gouy—Chapman theory. Experimental confirmation of these theoretical predictions have been restricted almost exclusively to studies performed on fine grain size fractions of montmorillonite. It seemed desirable to determine experimentally the effect of physico-chemical variables on the engineering properties of a more typical engineering material. The < 2 μ fraction of Fithian illite was selected.A study was made of the effect of variations in the pore water electrolyte concentration on the engineering properties of homoionic Ca- and Mg-illite. Pore water electrolyte concentrations ranged from 1 N down to about 10-4 N. Engineering tests included Atterberg limits, one-dimensional consolidation tests, and effective stress triaxial tests.The electrolyte concentration was found to have only a small effect on the Atterberg limits, the maximum limits occurring at electrolyte concentrations between 0.01 N and 0.1 N. For virgin consolidation the soil seemed strongest at about the same range in electrolyte concentrations but the effect was not large. Electrolyte concentration had almost no effect on the position of the rebound (swelling) curves. The most important effect of electrolyte concentration seemed to be its effect on the geometric arrangement of the particles for samples that were sedimented from dilute suspension. The geometric arrangement of particles seems to be a more significant variable than the osmotic repulsion between particles.There still appears to be merit in the old mechanical approach where the compression characteristics are explained by elastic bending (reversible), slippage (partially reversible), and rupture (irreversible) of particles. Double layer phenomena seem to exert a much smaller influence on the engineering properites of nonexpanding lattice clay minerals than is commonly inferred in the literature.
Influence of Adsorbed Water on Exchangeable Ion Movement
Authors: Low Philip F. 
Published: August 2006

AbstractThe concept of activation energy for ion movement is discussed. It is shown that the activation energy for exchangeable ion movement is directly correlated with the specific volume of the adsorbed water, with the resistance to freezing of this water and with the activation energy for deuterium oxide diffusion in this water. Electrical interaction between ion and clay appears to have little effect on the activation energy. Consequently, it is concluded that the most important factor governing exchangeable ion movement in the pores of a clay-water system is the structure of the adsorbed water.
Self-Diffusion of Exchangeable Cations in Bentonite
Authors: Lai T. M. , Mortland M. M. 
Published: August 2006

AbstractA special integral form of the solution of Fick's law was applied to study the self-diffusion of Na, Cs, and Ca ions in Wyoming bentonite plugs by means of a radioactive tracer technique. A simple procedure for measuring diffusion coefficients was developed by depositing a thin radioactive tracer film on the surface of clay mineral plugs at controlled temperatures. Thin sections of the clay plugs were removed and radioactivity measurements made on the portion of the plugs remaining. The self-diffusion coefficients of the ions were evaluated by a graphical method from the solution of Fick's law at special boundary conditions. Under oven-dry conditions at 105°C diffusion of Na ion in a bentonite film was observed, while in the same experiment, SO42− ion did not diffuse. In a clay-water system, however, the anion diffused much more rapidly than the cation. Based on the experimental results of observing Na22- and S35-tagged Na2SO4 diffusion, different diffusion paths were proposed using a picture of the clay matrix as a structure with “channels.” Diffusion coefficients of exchangeable cations decreased with increasing clay contents. From the results of activation energy and self-diffusion coefficients of Na and Ca ions at various clay-water concentrations, the relative “hopping distances” of diffusing ions were calculated and discussed. It is suggested that in the self-diffusion of exchangeable Na ion in bentonite the ion could be hopping from one individual clay plate to another, and the Ca ion from one “package” of plates to another “package” of plates.
Hydrothermal Products Formed From Montmorillonite Clay Systems
Authors: McCaleb Stanley B. 
Published: August 2006

AbstractAn investigation of the behavior of clay systems in drilling fluids was begun in 1958 to determine the cause of gelation in lime-treated muds with increased temperatures incurred during drilling operations. Mud systems were evaluated by physical property measurements, cation exchange data, X-ray diffraction analysis, and electron microscopy before and after hydrothermal treatment. Selected samples were rerun after two years' storage at laboratory temperatures.High-temperature gelation of lime-caustic muds is caused by the synthesis of calcium silicate hydrates, hereafter referred to as CSH, in general and tobermorite (XCaO, SiO2, H2O) specifically. These materials are considered the principal cementing agents of Portland cement. Spheroidal poorly crystallized tobermorite was produced from interlayered illite-montmorillonite muds. Laths and needles of crystalline tobermorite (11.3–11.6 Å type) were synthesized from the pure montmorillonite systems. Zeolite minerals were synthesized concurrently and were the dominant alteration product when Ca(OH)2 was not added to the system.Synthesized aged (2 years) mud systems were studied after 8 weeks of dialysis with distilled water. Corundum was observed in samples where tobermorite formed, and was the dominant insoluble residue after HCl treatment. Much sharper diffraction maxima were obtained of the CSH compounds after dialysis or glycerine washing.“Al-chlorite,” “Al-vermiculite,” and “Al-micas” were synthesized when treatments included aluminum ions. The products formed were of varying stabilities after washing with distilled water and HCl. Glycerol expanded the montmorillonite which had not reacted, but no expansion from the 10 Å or 14 Å d(001) spacing of the new product occurrred.
Halloysite and Gibbsite Formation in Hawaii
Authors: Bates Thomas F. 
Published: August 2006

AbstractDesilication and removal of bases from the basalitic rocks of the Hawaiian Islands produces large amounts of halloysite and gibbsite, together with variable quantities of allophane and nontronite, iron and titanium oxides, and amorphous mineral and gel material.The nature and relative abundance of intermediate and end products of weathering depend primarily upon the amount of rainfall, angle of slope, and texture of the rock. The formation of clay minerals is the common step in the transformation of primary silicates to oxides and hydroxides, but the amount and relative importance of the clay “stage” depend on the intensity of the weathering process.Halloysite forms from plagioclase usually by alteration of first the core and subsequently the rim of the feldspar laths. No kaolinite was observed, its absence being attributed to the absence of fine-grained mica as an intermediate weathering product.Gibbsite is produced by (1) removal of silica from halloysite, (2) dehydration of Al-gel, and (3) precipitation from solution. Although it is possible that the mineral may form directly from feldspar, halloysite is the common crystalline intermediate on both the megascopie and microscopic scales.An amorphous transition state, probably ranging in composition from allophane to Al-gel, exists as part of the change from halloysite to gibbsite as evidenced by electron microscope and diffraction work on pseudomorphs after halloysite tubes found in certain samples studied in more detail than others.Volcanic glass is the apparent source of most Al-Fe-Si gel material which upon dehydration becomes allophane, cliachite, or gibbsite depending on the kind and relative proportion of the cations present.
Clay Polymerization in Carbonate Rocks: A Silicification Reaction Defined
Authors: Bisque Ramon E. 
Published: August 2006

AbstractA carbonate rock silicification reaction has been defined and shown to be dependent on the presence of clay in the host rock. Introduction of silica in soluble form(s) serves to polymerize the clay fraction, forming a continuous three-dimensional network. This siliceous network (polymer) can be separated from the rock by leaching away the carbonate minerals. Laboratory silicification of argillaceous carbonate rocks under controlled conditions has served to define critical variables.Early studies were limited to argillaceous carbonate rocks from the Devonian Cedar Valley formation in eastern Iowa. Similar results have been obtained with carbonate rocks from the Devonian Chaffee formation in south-central Colorado. Some of the rocks in the latter formation have been silicified in nature, and yield siliceous polymers on acid leaching identical to those formed by silicification in the laboratory.The reaction defined is suggested to be common in natural diagenesis of argillaceous rocks, clay-rich sedimentary material, and soils.In the case of argillaceous carbonates this reaction affects physical properties of the rock which control processes involved in petroleum migration, ore-metal transfer, rock leaching and all diagenetic reactions that involve solution transfer.
Dehydration and Rehydration Studies of Clay Minerals by Infrared Absorption Spectra
Authors: Serratosa J. M. 
Published: August 2006

AbstractThe processes of dehydration and rehydration of montmorillonite and nontronite samples have been studied through infrared absorption spectra.The changes observed in the intensity of the bands during dehydration show the analogy between absorption at 915 cm-1 (montmorillonite) and at 820 cm-1 (nontronite), their origin being a deformation vibration of OH groups.During rehydration of the montmorillonite sample, the recovered OH groups occur in two different forms, in accordance with the results of differential thermal analysis.
Cation Exchange of Organic Compounds on Montmorillonite in Organic Media
Authors: McAtee James L. 
Published: August 2006

AbstractCation exchange of dimethyldioctadecylammonium (DMDO) ion for dimethylbenzyllauryl-ammonium (DMBL) ion previously reacted with centrifuged homoionic Na+ bentonite has been demonstrated. The amount of DMBL ion removed from the clay was determined by ultraviolet spectroscopy.In order to shift the exchange equilibrium toward removal of the DMBL cation, a large excess of DMDO cation was required. At the limit of these experiments, it was found that 16 percent of the DMBL cation was exchanged.
Controlled Synthesis of Heteropolytypic (Mixed-Layer) Clay Minerals
Authors: Iiyama J. T. , Roy Rustum 
Published: August 2006

AbstractThe conditions for the formation of various heteropolytypic or mixed-layer phases were determined in a hydrothermal study of synthetic mixtures along the join talc—Na-saponite—Na-phlogopite composition. Heteropolytypes of talc and saponite from compositions between talc and a saponite solid solution and of saponite and a 10 Å sodium mica (Na-phlogopite?) from compositions lying between saponite solid solutions and Na-phlogopite have been prepared reproducibly.At 1 kb in the temperature range 450-575° C, randomly stacked heteropolytypic phases were formed and persisted. At higher pressures the regular heteropolytypes (regularly interstratified or mixed-layer minerals), generally 1:1 phases, were formed. The genesis of heteropolytypes in nature is discussed on the basis of these results.
Relation of Diagenetic Alteration and Soil-Forming Processes to the Uranium Deposits of the Southeast Texas Coastal Plain
Authors: Weeks Alice D. , Eargle D. Hoye 
Published: August 2006

AbstractThe Upper Eocene Jackson Group is the chief host rock of the uranium deposits in the Karnes area of the southeast Texas Coastal Plain. It is highly tuffaceous and the uranium deposits are within approximately 100 ft of the unconformity with the overlying Catahoula Tuff (Miocene?). Glass shards, fragments of sanidine and plagioclase, grains of finegrained volcanic rocks, and biotite and other minerals in these sediments were highly reactive chemically, causing complex diagenetic alteration and the development of alkaline carbonate pore water. Extensive caliche development and silica induration associated with a recent hotter, drier climate favored the concentration of uranium. The origin of these shallow uranium deposits is believed to have been controlled by the complex diagenesis of the highly reactive volcanic detritus, by development of a “builtin” solvent for uranium (the alkaline carbonate pore water), and by climatic, structural, and permeability conditions that allowed concentration and deposition of uranium rather than dilution and dispersal. The tuffaceous rocks are considered to have been the source of the uranium and associated molybdenum, phosphorus, and arsenic.