Magnetic properties of sheet silicates; 1:1 layer minerals

Coey, J. M. D.; Ballet, O.; Moukarika, A.; Soubeyroux, J.L.

doi:10.1007/bf00308232

Cited by 54 publications

(37 citation statements)

References 8 publications

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“…values ranged between 2.49 and 8.43. These values are similar to those of Coey et al (1981) and Mackenzie and Berzowski (1984) where two doublet fits were also used. The second model, in which a three doublet fit was employed, achieved a closer approximation of the distribution of quadrupole splittings of Fe 2+ by fitting two doublets to the Fe z+ resonant absorption (Figure 9).…”

Section: Chemical Composition and Structural Formulaesupporting

confidence: 79%

“…viously (Yershova et al 1976(Yershova et al , 1982Mackenzie and Berezowski 1984). Non-equivalent FeZ+-octahedral sites likely exist because the octahedral sheet is not saturated with Fe z+ (Coey et al 1981). Substitution of trivalent (and possibly tetravalent) cations into the octahedral sheet causes distortion in both the size and symmetry of octahedral sites.…”

Section: Chemical Composition and Structural Formulaementioning

confidence: 99%

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Berthierine from the Lower Cretaceous Clearwater Formation, Alberta, Canada

Hornibrook

1996

Clays and clay miner.

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Abstract--Berthierine occurs as pore-linings of well crystallized laths of variable thickness in oil-sands of the Clearwater Formation, Alberta, Canada. Berthierine crystallized early in diagenesis within portions of a deltaic/estuarine complex dominated by brackish to fresh water.Separates prepared using high gradient magnetic separation contain approximately equal amounts of monoclinic and orthohexagonal berthierine. Minor, but variable, quantities of inseparable, iron-rich impurities mainly consist of chamosite Ib and lib, and Fe-rich smectitic clays.Clearwater Formation berthierine has a range of chemical compositions that differ from those reported for most other berthierines. The SiO2 (27-35 wt%), Fe203 (5-8 wt%) and A1203 (16-18 wt%) contents for Clearwater Formation berthierine fall between values normally reported for berthierine and odinite. The average structural formula of five samples studied in detail is (Fe2+~.olAloszMgo.46Fe3+o28 Mn<0.m[70.43)(Si1.74A10.26)Os(OH)4, where [] represents vacancies in the octahedral sheet. The large number of vacancies in the octahedral sheet implies a di-trioctahedral character for this clay. Our results also suggest that a series of compositions can occur between ideal berthierine and odinite end-members.Berthierine has been preserved within the Clearwater Formation because temperatures during diagenesis did not exceed 70~ and perhaps also because hydrocarbon emplacement limited subsequent transformation of berthierine to other phases, such as chamosite. Intense, early diagenetic, microbial activity and/ or the strongly reducing environment created by later emplacement of hydrocarbons may be responsible for the Fe>/Fe 3+ ratio of the berthierine. Because of these conditions, this ratio may have changed since initial clay crystallization. The Clearwater Formation occurrence of grain-coating Fe-rich clays provides valuable insights into possible relationships between the Fe-serpentine minerals, odinite and berthierine, and supports an important role for these phases as precursors to the grain-coating and pore-lining Fechlorite (chamosite) that is so common in ancient sandstones, including many hydrocarbon reservoirs.

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Section: Chemical Composition and Structural Formulaesupporting

confidence: 79%

Section: Chemical Composition and Structural Formulaementioning

confidence: 99%

Berthierine from the Lower Cretaceous Clearwater Formation, Alberta, Canada

Hornibrook

1996

Clays and clay miner.

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“…Mössbauer spectroscopy has revealed antiferromagnetic interaction in many silicates at low temperature [49][50][51]. The magnetic ordering temperatures of some silicates can be seen in Table 5.…”

Section: Antiferromagnetismmentioning

confidence: 99%

Critical review of analytical applications of Mössbauer spectroscopy illustrated by mineralogical and geological examples (IUPAC Technical Report)

Кузманн¹,

Nagy²,

Vértes³

2003

Pure and Applied Chemistry

122

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We have developed a new terminology for Mössbauer pattern analysis in order to enhance the performance of qualitative analysis by Mössbauer spectroscopy. In this approach, Mössbauer parameters are considered as a function of a number of externally adjusted experimental parameters at which the spectrum has been recorded. The basis of analytical classification is the microenvironment, which is determined by an assembly of atoms causing the same hyperfine interactions at one particular class of the Mössbauer probe atoms.Since Mössbauer spectroscopy measures hyperfine interactions very sensitively, the microenvironment presents itself as a fundamental concept for analytical purposes. Our approach can also help to systematize the Mössbauer data for the identification of individual physicochemical species from the corresponding patterns present in the spectrum.

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“…(53) On the other hand, recent magnetic studies on several Fe-containing sheet-silicate minerals (54,55) clarified the existence of a strong ferromagnetic interaction within the layer and a weak antiferromagnetic coupling between the layers. This magnetic structure is consistent with the magnetism of grunerite observed by Linares et al (18) Therefore, if one neglects the weak antiferromagnetic interlayer interaction as a first approximation, a two-dimensional magnetic lattice is obtained.…”

Section: Resultsmentioning

confidence: 99%