The Near-Infrared Combination Band Frequencies of Dioctahedral Smectites, Micas, and Illites

Post, J. L.; Noble, Paul N.

doi:10.1346/ccmn.1993.0410601

Cited by 198 publications

(105 citation statements)

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“…Figure 6 shows that the asymmetry of the 2200 nm peak of the SWIR spectra of the Athabasca illite separates appears to correlate positively with the Kübler index, except that several outliers are also notable. Post & Noble (1993) reported an influence on the position of the 2200 nm peak exerted by composition, and established a linear relationship between the 2200 nm band frequency and the Al content. Owing to the narrow range of the Al content of our illite separates, we could not evaluate this relationship.…”

Section: Illitementioning

confidence: 95%

The Characterization and Quantitative Analysis of Clay Minerals in the Athabasca Basin, Saskatchewan: Application of Shortwave Infrared Reflectance Spectroscopy

Zhang¹,

Wasyliuk²,

Pan³

2001

The Canadian Mineralogist

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The application of shortwave infrared (SWIR) reflectance spectroscopy to the characterization of clay minerals in the Athabasca Basin, in Saskatchewan, has been evaluated by detailed examination of 70 mineral separates (20 of kaolinite, 10 of dickite, 19 of illite, 16 of chlorites and 5 of magnesiofoitite). Clay minerals in the Athabasca Basin are widespread in the sandstones and are particularly abundant in alteration haloes associated with unconformity-type U deposits. SEM, TEM, XRD, EMPA, EPR and SWIR analyses confirm that dickite is a major clay mineral in the sandstones. Kaolinite from different geological settings has distinct values of crystallinity (i.e., Hinckley index in the range 0.84 to 1.61 in alteration haloes, 0.45 to 0.7 in the bleached zones of the paleoregolith, and 0.12 to 0.31 in late fractures and cavities). The SWIR reflectance spectroscopy is capable of quantitatively estimating the crystallinity of kaolinite by using a "14SP Index". Attempts to use SWIR reflectance spectroscopy for structural and compositional analysis of Athabasca illite and sudoite were complicated by the common occurrence of impurities in these minerals. Binary and ternary mixtures using well-characterized mineral standards reveal that SWIR reflectance spectroscopy is capable of identifying clay minerals at abundances as low as 1 wt%. Also, numerical relationships between spectral features and the abundances of clay minerals have been established from the muscovite -kaolinite, muscovite -dickite and muscovite -sudoite mixtures, and have been used to improve an empirical SWIR method for quantitative analysis of clay minerals in the Athabasca Basin. The estimated precision and accuracy of the improved empirical method are between 5 to 10%, comparable to those of conventional XRD methods. The detection limits of the SWIR method for samples containing multiple species of clay minerals are approximately 5 wt.% in relative abundance.Keywords: shortwave infrared reflectance spectroscopy, clay minerals, alteration assemblages, uranium deposits, Athabasca Basin, Saskatchewan. SOMMAIRENous avons évalué l'applicabilité de la spectroscopie par réflectance dans l'infra-rouge à ondes courtes (SWIR) pour caractériser les argiles du bassin d'Athabasca, au Saskatchewan, en utilisant soixante-dix concentrés (20 de kaolinite, 10 de dickite, 19 d'illite, 16 de chlorites et 5 de magnésiofoïtite). Les argiles sont répandues dans les grès du bassin d'Athabasca Basin, et surtout dans les auréoles d'altération associées aux gisements d'uranium localisés près d'une non-conformité. Les analyses par microscopie électronique à balayage et à transmission, par diffraction X, par microsonde électronique et par SWIR confirment que la dickite est une phase majeure dans les grès. La kaolinite provenant de divers contextes géologiques possède des valeurs distinctes de cristallinité (i.e., indice de Hinckley dans l'intervalle de 0.84 à 1.61 dans les auréoles d'altération, de 0.45 à 0.7 dans les zones lessivées du paléorégolithe, et de 0.12 à 0.31 ...

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Section: Illitementioning

confidence: 95%

The Characterization and Quantitative Analysis of Clay Minerals in the Athabasca Basin, Saskatchewan: Application of Shortwave Infrared Reflectance Spectroscopy

Zhang¹,

Wasyliuk²,

Pan³

2001

The Canadian Mineralogist

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“…However, the wavenumber of the gA1CrOH vibration band can be calculated from the NIR data, following this simple equation (Cariati et al 1981(Cariati et al , 1983a(Cariati et al , 1983bPost and Noble 1993;Bishop et al 1994…”

Section: Cr(iii)-kaolinitesmentioning

confidence: 99%

“…In practice, the band wavenumbers that are measured in the NIR region are close to the sum of the wavenumbers of bands observed in the MIR. Post and Noble (1993) pointed out that the small changes in the OH stretching and bending band positions are additive in the combination bands, making them more readily differentiated in the NIR region. This merit has been applied to the identification of clay mineral composition, particularly in the smectite group (Pontual and Cocks 1994;Post and Noble 1993).…”

Section: Introductionmentioning

confidence: 99%

“…Post and Noble (1993) pointed out that the small changes in the OH stretching and bending band positions are additive in the combination bands, making them more readily differentiated in the NIR region. This merit has been applied to the identification of clay mineral composition, particularly in the smectite group (Pontual and Cocks 1994;Post and Noble 1993). Delineau et al (1994) used NIR spectra to detect A1/ Fe(III) substitutions in natural kaolinites.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Octahedral Substitutions in Kaolinites Using Near Infrared Spectroscopy

Petit

Madejová

Decarreau

et al. 1999

Clays and clay miner.

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Abstract--Fourier transform infrared (FTIR) spectroscopy investigations in the near infrared (N1R) region of synthetic and natural kaolinites with various octahedral substitutions have been carried out in order to elucidate the relationships between the substituted cations and specific features of the NIR spectra. The combination modes of the OH stretching and bending vibrations characterizing Fe(III), Ga(III) and Cr(III) octahedral substitutions are identified in the NIR region at 4466, 4498 and 4474 cm ~, respectively, and the first overtones of the OH stretching vibrations at 7018, 7018 and 6986 cm -J, respectively. As far as we know, the bands of kaolinites containing Ga(III) or Cr(III) have not been reported yet. For both Ga(III) and Cr(HI), the NIR observations explain why the bending vibration bands of A1GaOH and A1CrOH groups are not observed in the middle infrared (MIR) region.

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“…Reflectance spectroscopy is an effective tool, commonly used to study and characterize clay minerals (e.g., Lyon and Green 1975;Clark et al 1990;Bishop et al 1993;Post and Noble 1994). Many researchers have studied isolated spectroscopic features or either the near-infrared region or the mid-infrared region of smectites.…”

Section: Introductionmentioning

confidence: 99%

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

Bishop

Pieters

Edwards

1994

Clays and clay miner.

381

256

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Abstract--Interlayer cations and moisture content greatly influence the molecular vibrations of H20 in montmoriUonite as shown through reflectance spectroscopy in the infrared. The absorptions due to H~O have been studied in montmorillonites exchanged with H, Na, Ca, Mg and Fe 3+ interlayer cations under variable moisture environments. Band assignments have been made for absorptions in the 3 ~tm region due to structural OH vibrations, symmetric and asymmetric 1-120 stretching vibrations and the H20 bending overtone. Changes in the energies of the absorptions due to H20 stretching vibrations were observed as the samples were dehydrated by reducing the atmospheric pressure. Absorptions near 3620 cm -1 and 3550 cm -1 have been assigned to water bound directly to cations (inner sphere) and surfacebonded H20 and absorptions near 3450 cm -1 and 3350 cm ~ have been assigned to additional adsorbed water molecules. Band assignments have been made for combination bands in the near-infrared as well. Absorptions near 1.41 ~m and 1.91/zm are assigned to bound H20 combination bands, while the shoulders near 1.46 izm and 1.97 ~*m are assigned to combinations of additional H20 molecules adsorbed in the interlayer regions and along grain surfaces.

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The Near-Infrared Combination Band Frequencies of Dioctahedral Smectites, Micas, and Illites

Cited by 198 publications

References 12 publications

The Characterization and Quantitative Analysis of Clay Minerals in the Athabasca Basin, Saskatchewan: Application of Shortwave Infrared Reflectance Spectroscopy

The Characterization and Quantitative Analysis of Clay Minerals in the Athabasca Basin, Saskatchewan: Application of Shortwave Infrared Reflectance Spectroscopy

Characterization of Octahedral Substitutions in Kaolinites Using Near Infrared Spectroscopy

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

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