Showing papers on "Clay minerals published in 1972"

Selective sorption and fixation of cations by clay minerals : A review

Abstract: Investigations concerning selective sorption and fixation of K and similar cations by clay minerals and soil clays and the mechanisms of these reactions are reviewed. In particular, recent observations on selective sorption of these ions in dilute solutions by weathered micas and vermiculite in relation to the interlayer structures are discussed in detail. Also, implications of the resistance to weathering of small mica particles to cation selectivity by soils are described. Despite the increased understanding of sorption and fixation reactions, the following aspects remain unclear. First, the mechanism of the collapse of alternate layers in vermiculite on K or Cs sorption has not been unequivocally established. Second, factors that impart stability to the central core of mica particles so that K extraction becomes progressively difficult are not known. Third, inability of Ca or Mg ions to expand interlayers of Cs-saturated vermiculite in contrast to K-saturated vermiculite is not completely understood.

Selective sorption and fixation of cations by clay minerals: a review

Abstract: Investigations concerning selective sorption and fixation of K and similar cations by clay minerals and soil clays and the mechanisms of these reactions are reviewed. In particular, recent observations on selective sorption of fhese ions in dilute solutions by weathered micas and vermiculite in relation to the interlayer structures are discussed in detail. Also, implications of the resistance to weathering of small mica particles to cation selectivity by soils are described. Despite the increased understanding of sorption and fixation reactions, the following aspects remain unclear. First, the mechanism of the collapse of alternate layers in vermiculite on K or Cs sorption has not been unequivocally established. Second, factors that impart stability to the central core of mica particles so that K extraction becomes progressively difficult are not known. Third, inability of Ca or Mg ions to expand interlayers of Cs-saturated vermiculite in contrast Co K-saturated vermiculite is not completely understood.

Authigenic Aluminosilicate Minerals in the Tuffaceous Rocks of the Green River Formation, Wyoming

Abstract: The Green River Formation of Wyoming was deposited in a large lake, Lake Gosiute, during Eocene time. Throughout Lake Gosiute9s existence, nearby volcanism supplied debris to the lake basin. Tuffs are abundant and widespread in the formation and were highly reactive units. Reaction between glass and the lake waters produced authigenic clay minerals, mordenite or clinoptilolite, analcime, and potassium feldspar. Some tuffs are almost entirely replaced by authigenic aluminosilicate minerals. The alteration of the tuffs shows a systematic pattern with the clay mineral and zeolite alteration restricted to facies formed in relatively fresh water, and the feldspar alteration is confined to a hypersaline facies. We infer that the lake water ranged from fresh or brackish (SiO 2 = 10 ppm, K = 50 ppm, Na = 1,000 ppm) at a pH of 8.0 during the “fresh-water stage” to hypersaline (SiO 2 = 1,000 ppm, K = 5,000 ppm, Na = 100,000 ppm) at a pH of 9.0 to 10.0 during the most saline and alkaline stage. Brines were formed primarily by evaporative concentration. Organisms, reflected by abundant high-yield oil shales, thrived during the freshwater episodes, but were apparently absent or of minor significance during the hypersaline episodes; this is reflected by the presence of thick beds of trona and halite.

Layered clay minerals, catalysts, and processes for using

Abstract: A layer-type trioctahedral, clay-like mineral having the empirical formula MgO : sSiO2 : aAl2O3 : bAB : xH2O wherein the layer-lattice structure is composed of said silica, said alumina, said magnesia, said A and said B, and wherein S IS FROM 0.66 TO 1.33, PREFERABLY 1.0

Layered clay minerals and processes for using

Abstract: A layer-type, dioctahedral, clay-like mineral having the empirical formula MgO : sSiO2 : aAl2O3 : bAB : xH2O wherein the layer-lattice structure is composed of said silica, said alumina, said magnesia, said A and said B, and wherein S IS FROM 1.4 TO 100, PREFERABLY 2.0

Diffuse reflectance spectra of several clay minerals

Abstract: The diffuse reflectance spectra in the 0.3 to 2.1 micrometer wavelength region have been measured for several sa,mples of clay minerals sometimes found in the atmospheric aerosol. Exa.mples of spectra are shown for different hydration states of several montmorillonite and kaolin group minerals. It was found that these clays show absorption features in the wavelength regions where liquid water absorbs. These absorption bands are removed by dehydration, as would be expected. It is concluded that the major features of the near infrared absorption spectra of montmorillonite and kaolin clays are determined primarily by the water present in the clay stmctures. In addition, the spectra show evidence of strong absorption in the near ultraviolet and short wavelength visible region. This latter absorption is a general feature of all the clay samples investigated.

Effect of Several Clay Minerals and Humic Acid on the Survival of Klebsiella aerogenes Exposed to Ultraviolet Irradiation

Abstract: The effect of various clay minerals and humic acid on the survival of Klebsiella aerogenes exposed to ultraviolet (UV) irradiation was investigated. A protective effect was observed and found to depend on the specific light absorption and light scattering properties of the clay minerals and the humic acid used. The higher the specific absorption, the better was the survival of K. aerogenes after UV irradiation. Bacterial survival was lower in clays saturated with divalent cations (Ca, Zn) than in those homoionic to monovalent cations (K).

Weathering of micaceous clays in some norwegian podzols

Abstract: A study of the weathering of micaceous clays in some Norwegian podzols, includes semiquantitative estimates of minerals in the concentrated clay fractions which show a decrease in the amounts of illite and chlorite, and an increase in vermiculite and mixed-layer minerals upward in the profile. Illite, the dominant mineral at depth, weathers to hydrobiotite in the surface horizon of the profile. Subsequent weathering of hydrobiotite in this portion of the profile produces trioctahedral vermiculite and smectite, or inter- grade smectite-chlorite.

Mineralogy and Origin of Clay Minerals, Silica and Authigenic Silicates in Leg 14 Sediments

Abstract: Preliminary X-ray, SEM, TEM, and optical mineralogical results are reported to discuss the paragenesis, age distribution, and origin of clay minerals, silica modifications and authigenic silicates found in nine drilling sites of Leg 14 of the Deep Sea Drilling Project, located off northwestern Africa and northeastern South America. Most noncarbonate minerals are diagenetic alteration products of volcanic ashes. Continent-derived clay minerals, such as mica-illite, kaolinite, and chlorite (rare), are frequent only in terrigenous sediments, especially off the Amazon River and off Cape Blanc. Smectites, mainly normal montmorillonite (+greenish ?nontronite, and hectorite-saponite), are the dominant clay minerals in sediments of all ages and sites. Montmorillonite, ultimately derived from the decomposition of volcanic glass, is especially abundant in volcanogenic clays and ashes, nannofossil marl-oozes, hemipelagic siliceous oozes, and brown pelagic clays. A mixed-layer mineral, consisting of regularly interstratified chlorite and trioctahedral montmorillonite, occurs mainly in pelagic clays. Four types of amorphous or microcrystalline silica were observed in siliceous oozes and silicified mudstones and bedded cherts: (a) unaltered, amorphous opal (in siliceous organisms); (b) unidimensionally disordered low-cristobalite (-tridymite), either cryptocrystalline ("opal-cristobalite") or as fibrous "lussatite" needles, slowly crystallizing from closely-packed silica gel spheres (in cherts of intermediate maturity); (c) macrocrystalline fibrous chalcedony; and (d) crystocrystalHne quartz, commonly filling recrystallized radiolarian tests and forming the matrix of homogenized, mature, quartz-rich cherts. Palygorskite, commonly associated with small amounts of sepiolite, is an abundant constituent of volcanogenic white (and brown) clays, carbonaceous clays, some siliceous muds, "white" lussatite cherts, and pelagic clays, all of Latest Cretaceous to Paleogene age. A diagenetic origin from degraded bentonitic clays by precipitation from magnesium-rich solutions with excess silica, derived from the devitrification of silicic ash and/or the dissolution of opaline organisms is suggested. The maximum occurrence of sepiolite is farther from shore than that of palygorskite. Authigenic clinoptilolite, the only zefolite identified in all sites, has a similar age range (minimum age: Middle Miocene; minimum depth of burial: 120 meters) and paragenesis as palygorskite. It has also been formed diagenetically from the devitrification of volcanic glass and palagonite, especially in pelagic and volcanogenic brown clays and black carbonaceous shales, and at least 20 million years after their deposition. High-temperature sanidine, possibly also of authigenic origin by hydrothermal solutions, was found in Late Cretaceous pyroclastic clays and altered vitreous ashes, associated with volcanic glass, palagonite, and montmorillonite.

Iron and Clay in Tropical Savanna Alluvium, Northern Colombia: A Contribution to The Origin of Red Beds

Abstract: Along the flanks of Sierra Nevada de Santa Marta, northern Colombia, tropical savanna uplands with reddish to reddish-brown soils yield brown alluvium which contains relatively abundant grains of fresh iron-bearing minerals: magnetite, amphibole, and biotite, with subordinate chlorite and ilmenite. They constitute about 4.5 weight percent of bulk samples and 8.8 weight percent of sand-silt fractions. In older terrace deposits bleached biotite is common, amphibole is rare, and some magnetite has been oxidized to specular hematite. Clay minerals consist of varying amounts of montmorillonite, illite, mixed-layer clay, kaolinite, and chlorite. Amorphous to very disordered aluminosihcate constitutes 10 to 26 percent of the clay fraction. Total iron makes up 3.1 to 7.6 percent of bulk samples which is considerably higher than that in Sonoran Desert alluvium (0.7 to 4.7 percent), and its upper range exceeds that in many ancient red beds. With few exceptions most of the total iron is in the clay fractions and about 75 percent of that is combined in clay minerals. Total iron in clay fractions averages about 6.6 percent: 5.5 to 8.0 percent in alluvium in transit, 4.8 to 9.0 percent in flood-plain sediments, and 3.0 to 5.8 percent in older terrace deposits. Free (extractable) iron in brown pigment constitutes 0.7 to 3.2 percent of clay fractions and averages about 0.75 percent of bulk samples. This is about twice that in bulk samples of Sonoran Desert alluvium (0.38 percent mean) and it is more than that in many ancient red beds (0.67 percent mean). According to these data there is enough free brown hydrated ferric oxide in tropical savanna alluvium to produce hematite pigment in a red bed simply by post-depositional dehydration and crystallization in an oxidizing environment of burial.

Potassium reserves in a ‘harwell’ series soil

Abstract: Summary A sample of Harwell soil containing 36 percent fine clay (< 0.3 μm) and 14 per cent coarse clay plus fine silt (0.3–5μm) was separated into fractions, and the K-supplying power of soil and fractions measured by cropping with ryegrass, exchange with Ca resin and double-label isotopic exchange with 42K and 45Ca ions. Mineralogical examination of the fractions coupled with the cropping experiments showed that the K-supplying power of the soil to ryegrass can be explained by the presence of a zeolite, clinoptilolite-heulandite, in addition to the clay minerals, mica, and interstratified illitic smectite, commonly found in a glauconitic clay-rich soil. The 0.3–5 μm fraction, containing much zeolite, has an exchange diffusion coefficient for K ions to Ca resin of 1.8 × 10−16 cm2sec−1 compared with a value of 5.7 × 10−20 for the < 0.3μm fractions in which interstratified illitic smectite is the dominant mineral. Isotopic exchange shows that all Ca ions in fractions < 50μm are isotopically exchangeable. In fractions coarser than 20μm, some of the K ions in felspar and mica were not exchangeable within the duration of the experiments.

Use of the liquid limit in characterizing clay soils

Abstract: An index property for clay soils is sought to give the information that grain size gives about coarse-grained soils. The liquid limit is suggested as such an index property. The liquid limit is closely related to surface area for clay soils containing tabular clay minerals. This relation exists also for soils containing allophane or amorphous material. In addition to estimating surface area, liquid limit also gives information about the nature of the surface. In this respect it is a more useful measurement than clay content.

An aspect of the water in clay minerals: an application of nuclear magnetic resonance spectrometry to clay mineralogy

Abstract: is a broad band with maximum near 8400 cm-'. The absorption line width of wideJine NMR with water in allophane, is 0.12 gauss 3ll-\"r, and expands to 0.8 gauss on drying at 110\"C. The infrared absorption spectrum of allophane shows a broad atrsorption band near 8480 or B4go cm-r associated with o-rr stretching vibration. Protons in allophane are almost completely exchanged by deuterons, and a large number of the hydroryl groups are released from allophane by fluoride. These results suggest for the properiies of the water in allophane: comparatively unstable hydroxyl group, wea.k adsorption of water, continuous exchange of proton between adsorbed water and structural hydroxyl groups, and difference from so-called ,,zeolite water.\" Exchangeable proton content is determined by high-resolution NMR speetrometry.

The distribution and extraction of soil nitrogen as a function of soil particle size

Abstract: Two surface soils, a red-brown earth and a lateritic podzolic, have been fractionated with respect to soil particle size and the distribution of organic matter and nitrogen through these fractions determined Each fraction was extracted sequentially with 01 m sodium pyrophosphate and twice with 05 n sodium hydroxide (at 20°C and 60°C) The distribution of nitrogen through the residues and extracts was then determined Most of the organic matter was present either as recognisable organic particles in various stages of humification or as components intimately associated with clay minerals The nitrogen content of the organic matter was found to increase as the particle size decreased, the organic matter associated with clay having the highest nitrogen contents The humic acid extracts did not reflect this variability and gave relatively constant values for nitrogen content The unextracted organic matter had a low nitrogen content showing that the nitrogenous components were preferentially extracted Recovery of nitrogen was incomplete due to partial volatilization during alkaline extractions

Clay Minerals of the Green River Formation (Eocene) of Wyoming

Abstract: X-ray analyses indicate that illite, smectite, loughlinite (Na20.3MgO. 6SIO2.8H20) and chlorite are present in the < 2/zm fraction of the lacustrine Green River Formation (Eocene) of Wyoming. Material amorphous to X-rays and random mixed-layer structures are present in subordinate amounts. Individual crystals vary from pure, well-ordered structures to poorly crystallized forms. Illite is ubiquitous, occurring in all the samples studied. It is generally associated with other clay minerals but frequently occurs as the only clay mineral found in the 'oil shales'. Smectite is present in all three members of the Green River Formation, but its presence frequently shows an inverse relationship to both analcime and loughlinite. Loughlinite is restricted to the saline facies of the Wilkins Peak Member. Chlorite occurs only in the silty and sandy beds of the Tipton Shale Member. The distribution of random mixed-layer structures and amorphous material is irregular. Several independent lines of evidence favour an in situ origin for many of the clay minerals reported in this investigation. The 'oil shales', which are in most cases varved, kerogenous, dolomitic marls, have a variable clay mineral composition. There is a marked tendency, however, for illite to be the dominant or the only clay mineral present. Apparently the geochemical conditions favouring the accumulation of the oil shales also favoured in situ generation of illite.

Weathered Interstadial Green Clay at Port Talbot, Ontario

Abstract: The geologic origin of a distinctive layer of green, weathered clay belonging to the lower part of the Port Talbot Interstadial sediments (Port Talbot I) on the north shore of Lake Erie has been reinterpreted in relation to its clay mineralogy, carbonate content, and pollen dataIn addition to illite and chlorite, both characteristic of all clayey glacial sediments in the area, the green clay contains abundant smectite probably produced by oxidation weathering of chlorite in the Bradtville Till Carbonate contents, normally less than 1% in the green clay compared to values of 15 to 45% in the overlying and underlying sediments, indicate extensive solution weatheringThe green clay layer is interpreted to be an accretion gley, weathered in a soil profile during the early part of the Port Talbot Interstadial and subsequently eroded and deposited in poorly drained depressions under reducing conditions An abundance of oak, pine, and spruce pollen indicate a fairly temperate climate at the beginning of Port T

Clay mineral synthesis -- iii rapid hydrothermal crystallization of an aluminian smectite

Abstract: An aluminian smectite with about one Al3+/Si4+ replacement per unit cell was batch- synthesized on a large scale (100-gal autoclave) at 3 00°C and 1240 psig with reaction times of several hours rather than days. This rapid crystallization was related to the use of NH4+ as the charge-balancing cation and to partial F/OH substitution. The short synthesis time prompted a study of continuous crystallization. Either of two techniques, flow through a stirred autoclave and through a multi-staged reactor column, produced crystalline product; neither gave the crystallinity of the batch process.