Chemical dissolution techniques in the study of soil clays: Part I

Clay Minerals ◽  
1965 ◽  
Vol 6 (1) ◽  
pp. 23-34 ◽  
Author(s):  
E. A. C. Follett ◽  
W. J. McHardy ◽  
B. D. Mitchell ◽  
B.F.L. Smith
Keyword(s):  
Infrared Absorption ◽  
Inorganic Material ◽  
Clay Fraction ◽  
Glacial Till ◽  
Soil Profiles ◽  
Chemical Dissolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Soil Clays ◽  
End Members

AbstractThe mineralogy of the clay fractions of two soil profiles representing the end-members of a catena developed on a glacial till derived from basic lavas has been determined. Particular attention has been given to the assessment of the nature of the amorphous inorganic material in the clay fraction of these soils. Chemical dissolution techniques were used and their effects on the clay fraction were followed by X-ray diffraction, differential thermal, infrared absorption, electron-optical and surface area measurements. The principal conclusion is that the soil clays are a continuum from completely disordered, through poorly ordered to well crystallized material.

High-spacing irregularly interstratified layer-silicates in the alluvial soil clays of Meerut, India

Clay Minerals ◽  
1985 ◽  
Vol 20 (1) ◽  
pp. 115-124 ◽  
Author(s):  
K. P. Tomar
Keyword(s):  
Alluvial Soil ◽  
Clay Fraction ◽  
Alluvial Plain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Soil Clays ◽  
Ap Horizon ◽  
Fine Clay ◽  
Xrd Patterns

AbstractThe mineralogy of the fine clay fraction (<0·2 μm) of two soil pedons (Aquic and Udic Haplustalfs) representing the wheat-sugarcane belt of the Indo-Gangetic alluvial plain was studied by X-ray diffraction, differential thermal analysis, transmission electron microscopy, and by chemical analysis. The XRD patterns are characterized by unusually high spacings which are interpreted in terms of an interstratification comprising smectite, illite and ‘chlorite’ components. The CEC data (Ca/Mg and K/NH4) also indicate the possible presence of vermiculite. A plateau bridging the 7–10 Å maxima in K-saturated specimens heated at 300°C suggests interstratification of kaolinite and smectite, although this may not be part of the above interstratification. The diffuse bands shown by Mg-glycerol-solvated Ap-horizon clays at ∼21 Å, and the increasing elimination of XRD peaks in the > 10 Å region with distance from the surface, suggests that the expanding layers have a slight tendency to segregate in Ap horizon samples and that randomization tends to increase with depth. Discrete illite and small amounts of kaolinite were also detected.

Allophanic material in Australian soils derived from Pleistocene basalt

Soil Research ◽  
1969 ◽  
Vol 7 (2) ◽  
pp. 163 ◽  
Author(s):  
GP Briner ◽  
ML Jackson
Keyword(s):  
Clay Fraction ◽  
Thermal Infrared ◽  
Molar Ratio ◽  
Chemical Dissolution ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Microscopic Techniques

The clay fraction of four soils derived from Pleistocene basalt in Victoria, under a Mediterranean type climate, have been studied by X-ray diffraction, differential thermal, infrared, and electron microscopic techniques. Their chemical dissolution with alkali has shown that they contain about 25 % of allophane having a SiO2/Al2O3 molar ratio of about 4. This ratio is higher than that reported for sesquioxidic allophane and halloysitic allophane, and the name 'siliceous allophane' is proposed.

OCCURRENCE AND DETERMINATION OF LEPIDOCROCITE IN CANADIAN SOILS

1979 ◽  
Vol 59 (2) ◽  
pp. 155-162 ◽  
Author(s):  
G. J. ROSS ◽  
N. M. MILES ◽  
H. KODAMA
Keyword(s):  
Acid Soils ◽  
Chemical Dissolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Shape Characteristic ◽  
Soil Clays ◽  
Canadian Soils ◽  
Soluble Aggregates ◽  
Diffraction Patterns

Lepidocrocite occurred in B and C horizons of several poorly drained, acid soils; it was determined by X-ray diffraction, electron optical, and chemical dissolution methods. A comparison of X-ray diffraction results obtained by diffractometer, Debye-Scherrer and Guinier-de Wolff methods showed the latter method to be superior in providing the more distinct and complete evidence of lepidocrocite in soil clays. Dithionite-soluble aggregates commonly had a dumbbell-like shape characteristic of lepidocrocite but their electron diffraction patterns were similar to those of maghemite. This suggested the topotactic dehydroxylation of lepidocrocite in the electron microscope. Amounts of lepidocrocite estimated from X-ray diffraction intensities agreed fairly well (within 2.5%) with amounts calculated from iron dissolved by dithionite and oxalate treatments. Lepidocrocite concentrations in soil clays of 1–2% gave distinct X-ray diffraction evidence.

XVI.—Distribution in some Scottish Soils of an Inorganic Gel System related to “Allophane”

1966 ◽  
Vol 66 (16) ◽  
pp. 393-418 ◽  
Author(s):  
J. H. Kirkman ◽  
B. D. Mitchell ◽  
R. C. Mackenzie
Keyword(s):  
Quantitative Estimation ◽  
Soil Profiles ◽  
Chemical Dissolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particle Size Fractions ◽  
North East ◽  
Infra Red ◽  
Optical Examination ◽  
Gel System

SynopsisSamples from the various horizons of five soil profiles representative of diverse types widely occurring in north-east Scotland were intensively examined, after separation into particle-size fractions, by appropriate instrumental and chemical techniques including optical examination, X-ray diffraction, electron microscopy and diffraction, infra-red absorption spectroscopy, thermal analysis procedures, chemical analysis and selective chemical dissolution. The results obtained are presented and assessed with respect to quantitative estimation of the mixed SiO2-Al2O3-Fe2O3 gel system occurring in these soils. At best results can be only semiquantitative, but interesting trends are observable in each profile and marked differences are noted between profiles on different parent materials, although this effect is somewhat obscured under impeded drainage conditions. The maturity of the soil is also a significant factor. Results in general can be explained in terms of current concepts on pedogenesis.

scholarly journals Provenance and Sedimentary Context of Clay Mineralogy in an Evolving Forearc Basin, Upper Cretaceous-Paleogene and Eocene Mudstones, San Joaquin Valley, California

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Andrew Hurst ◽  
Michael Wilson ◽  
Antonio Grippa ◽  
Lyudmyla Wilson ◽  
Giuseppe Palladino ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Upper Cretaceous ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Bulk Rock ◽  
X Ray Diffraction ◽  
Arc Volcanism ◽  
X Ray ◽  
Magmatic Arc ◽  
Tropical Weathering

Mudstone samples from the Moreno (Upper Cretaceous-Paleocene) and Kreyenhagen (Eocene) formations are analysed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) to determine their mineralogy. Smectite (Reichweite R0) is the predominant phyllosilicate present, 48% to 71.7% bulk rock mineralogy (excluding carbonate cemented and highly bio siliceous samples) and 70% to 98% of the <2 μm clay fraction. Opal CT and less so cristobalite concentrations cause the main deviations from smectite dominance. Opal A is common only in the Upper Kreyenhagen. In the <2 μm fraction, the Moreno Fm is significantly more smectite-rich than the Kreyenhagen Fm. Smectite in the Moreno Fm was derived from the alteration of volcaniclastic debris from contemporaneous rhyolitic-dacitic magmatic arc volcanism. No tuff is preserved. Smectite in the Kreyenhagen Fm was derived from intense sub-tropical weathering of granitoid-dioritic terrane during the hypothermal period in the early to mid-Eocene; the derivation from local volcanism is unlikely. All samples had chemical indices of alteration (CIA) indicative of intense weathering of source terrane. Ferriferous enrichment and the occurrence of locally common kaolinite are contributory evidence for the intensity of weathering. Low concentration (max. 7.5%) of clinoptilolite in the Lower Kreyenhagen is possibly indicative of more open marine conditions than in the Upper Kreyenhagen. There is no evidence of volumetrically significant silicate diagenesis. The main diagenetic mineralisation is restricted to low-temperature silica phase transitions.

The wulfenite—stolzite series: centric or acentric structures?

2008 ◽  
Vol 72 (4) ◽  
pp. 987-990 ◽  
Author(s):  
L. Secco ◽  
F. Nestola ◽  
A. Dal Negro
Keyword(s):  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
End Members ◽  
Symmetry Change

AbstractThree natural crystals of the wulfenite (PbMoO4)—stolzite (PbWO4) series were investigated by single-crystal X-ray diffraction. The results indicate that the symmetry is I41/a from nearly pure wulfenite to intermediate compositions, in contrast to previous work which claimed a symmetry change to 74 symmetry (acentric) for intermediate compositions compared with I41/a (centric space group) for the end-members. The results reported here show that the reflections violating I41/a symmetry observed in this work and in a previous study are related primarily to λ/2 effects, even if Renninger effects are not excluded. Consequently, we find that the I41/a symmetry is retained throughout the wulfenite— stolzite.

Crystal-chemical aspects of the roméite group, A2Sb2O6Y, of the pyrochlore supergroup

2017 ◽  
Vol 81 (6) ◽  
pp. 1287-1302
Author(s):  
Ferdinando Bosi ◽  
Andrew G. Christy ◽  
Ulf Hålenius
Keyword(s):  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Structural Parameters ◽  
Chemical Information ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Structural Variations ◽  
X Ray ◽  
End Members ◽  
Charge Balancing

AbstractFour specimens of the roméite-group minerals oxyplumboroméite and fluorcalcioroméite from the Långban Mn-Fe deposit in Central Sweden were structurally and chemically characterized by single-crystal X-ray diffraction, electron microprobe analysis and infrared spectroscopy. The data obtained and those on additional roméite samples from literature show that the main structural variations within the roméite group are related to variations in the content of Pb2+, which is incorporated into the roméite structure via the substitution Pb2+→A2+ where A2+ = Ca, Mn and Sr. Additionally, the cation occupancy at the six-fold coordinated B site, which is associated with the heterovalent substitution BFe3+ + Y☐→BSb5++YO2-, can strongly affect structural parameters.Chemical formulae of the roméite minerals group are discussed. According to crystal-chemical information, the species associated with the name ‘kenoplumboroméite’, hydroxycalcioroméite and fluorcalcioroméite most closely approximate end-member compositions Pb2(SbFe3+)O6☐, Ca2(Sb5+Ti) O6(OH) and (CaNa)Sb2O6F, respectively. However, in accord with pyrochlore nomenclature rules, their names correspond to multiple end-members and are best described by the general formulae: (Pb,#)2(Sb,#)2O6☐, (Ca,#)2(Sb,#)2O6(OH) and (Ca,#)Sb2(O,#)6F, where ‘#’ indicates an unspecified charge-balancing chemical substituent, including vacancies.

scholarly journals The Occurrence of Authigenic Clay Minerals in Alkaline-Saline Lakes, Pantanal Wetland (Nhecolândia Region, Brazil)

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 718
Author(s):  
Isis Armstrong Dias ◽  
Leonardo Fadel Cury ◽  
Bruno Guimarães Titon ◽  
Gustavo Barbosa Athayde ◽  
Guilherme Fedalto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Clay Minerals ◽  
Saline Lakes ◽  
Clay Fraction ◽  
Water Bodies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Fine Clay ◽  
Pantanal Wetland

Mg clay minerals are usually associated with carbonates in alkaline-saline environments, precipitated from solution and/or transformation from other minerals. The aim of this research is to identify the mineralogy and geochemistry of clay minerals in different alkaline lakes in the Nhecolândia region, the southernmost region of the Pantanal wetland (Brazil). Sediment samples were analyzed by X-ray diffraction, X-ray fluorescence, scanning electron microscopy and transmission electron microscopy. Water samples were analyzed, determining their main cations and anions, in order to understand their relationship with the clays. The analyses allowed classifying the water bodies as saline, oligosaline and freshwater lakes. The sediments are composed mainly of quartz and a fine-clay fraction, dominated by illite, kaolinite and smectite. The XRD results showed illite and smectite mixed-layered in the saline lakes at Barranco Alto farm, whereas at Nhumirim farm, trioctahedral smectite was only observed in one lake. The smectite minerals were normally identified coupled with calcite at the top of the sequences, associated with exopolymeric substances (EPS) in the lakes, suggesting that these minerals are precipitating due to the physical-chemical and biological conditions of the water bodies.

A method to study the effect of chemical dissolution on the morphology of soil clay

Clay Minerals ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 315-318
Author(s):  
M. Hagiwara
Keyword(s):  
Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Inorganic Material ◽  
Morphological Changes ◽  
The Other ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Chemical Dissolution ◽  
Soil Clays ◽  
Soil Clay

Soil clays contain a relatively large amount of disordered inorganic material. Chemical dissolution has been used for the removal of this material (Jackson, 1956; Hashimoto & Jackson, 1960; Follett et al, 1965 a,b; Wada & Greenland, 1970). On the other hand, Farmer et al. (1977) claimed that dissolution of allophane and imogolite with hot 5% Na2CO3 for periods of 2-100 h led to new phases which could be distinguished from the starting material by infrared spectroscopy. It is clear, therefore, that chemical dissolution can alter soil clays. This note suggests an electron microscopy specimen preparation technique to study the morphological changes. Collodion films containing densely arranged minute hollows are used for specimen supports.

Swelling minerals in a basalt and its weathering products from Morvern, Scotland: I. Interstratified montmorillonite-vermiculite-illite

Clay Minerals ◽  
1980 ◽  
Vol 15 (4) ◽  
pp. 445-451 ◽  
Author(s):  
D. C. Bain ◽  
J. D. Russell
Keyword(s):  
Clay Mineral ◽  
Infrared Absorption ◽  
Aluminium Content ◽  
X Ray Diffraction ◽  
Thermal Methods ◽  
X Ray ◽  
Absorption Pattern ◽  
Three Components

AbstractThe main clay mineral in weathered basaltic rubble has been shown by X-ray diffraction, chemical, infrared and differential thermal methods to be an interstratification of montmorillonite, vermiculite and illite in the approximate ratio 2:1:1, the montmorillonite having some degree of segregation and the vermiculite and illite being randomly interstratified. All three components are dioctahedral, the swelling ones having a high tetrahedral charge, a large aluminium content, and very little iron. Despite the 50% montmorillonite content of the mineral, its infrared absorption pattern is generally illitic in character.

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