Electron spin resonance and related studies of lignite and ball clay from South Devon, England

Hall, Peter G.; Angel, B. R.; Braven, J.

doi:10.1016/0009-2541(74)90002-3

Cited by 35 publications

(13 citation statements)

References 24 publications

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“…Type C In all shale samples, a sharp reso nance line was observed near gaff = 2. A similar resonance has been found to appear in the spectra of natural carbonaceous materials (UEBERSFELD et al, 1954;DUCHESNE et al, 1961 ;HALL et al, 1974;SIDWELL et al, 1979) Fig. 3.…”

Section: Results Ans Discussionsupporting

confidence: 71%

“…A similar reso nance was recognized in some clays and clay minerals (HALL et al, 1974;MEADS and MALDEN, 1975;ANGEL and VINCENT, 1978), micas (KEMP, 1971(KEMP, , 1972 and organic materials containing Fe(III) (WICKMAN et al, 1965;CHESHIRE et al ., 1977;SENESI et al, 1977).…”

Section: Mentsupporting

confidence: 56%

“…In particular, a number of ESR studies have been made on clay minerals and related materials (KEMP, 1971(KEMP, , 1972ANGEL and HALL, 1973;HALL et al, 1974;MEADS and MALDEN, 1975;ANGEL and VINCENT, 1978). However, ESR spectra of the shale, which is composed of some minerals in cluding clay minerals, have not been examined yet.…”

Section: Introductionmentioning

confidence: 99%

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Electron spin resonance and distribution of some elements in shales

1981

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Five types of ESR signals were observed in shales. The resonance composed of six lines near geff = 2 (type A) is attributed to Mn(II). Type A resonance is divided into two groups on the basis of its line shape; one exhibits six sharp lines (type A-1), and another shows relatively broad lines (type A-2). The geff = 2 broad resonance (type B) may be attributed to Fe(III). The geff = 2 sharp resonance line (type C) probably results from stable organic free radicals. The geff = 4.1 resonance (type D) can be attributed to high spin Fe (III) occupying sites of orthorhombic symmetry in clay minerals. Some of the shales show an inclined signal covering a wide magnetic field (type E).Combination of ESR measurements and leaching experiments made it possible to survey the distribu tion and states of some elements in shales. In shales which exhibit type A-1 resonance overlapped with type A-2 resonance, Mn (II) is randomly distributed both in calcite and clay minerals. In shales which exhibit only type A-2 resonance, Mn (II) is associated mainly with clay minerals. Most of the iron in shales is bound to clay minerals. A part of the iron in clay minerals is present as Fe (III) which shows type D resonance.

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Section: Results Ans Discussionsupporting

confidence: 71%

Section: Mentsupporting

confidence: 56%

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Electron spin resonance and distribution of some elements in shales

1981

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“…This led us to conflicting interpretations. The organic-carbon contents of decarbonated samples are low (Table 1), and the inorganic matrix can be held responsible for these spectra, which seem at first glance comparable with these found for ball clay by Hall et al (1974). Those authors have shown for clays asymmetric spectra at g = 2.003, which is a g value generally found for organic matter (Baker et al, 1978).…”

Section: Electron-spin Resonancesupporting

confidence: 62%

Preliminary Results of Petrographic and Electron-Spin-Resonance Studies of Organic Matter from Deep Sea Drilling Project Sites 370 and 416

Boutefeu¹,

Leplat²,

Somers³

1980

Initial Reports of the Deep Sea Drilling Project

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Petrographic observations confirm the continental origin of the organic matter and the presence of reworked, altered organic material in the sediments from DSDP Sites 370 and 416. The reflectance of the primary vitrinite-huminite population establishes that these samples are in the mature stage of evolution. The very low organic-carbon content of these samples makes ESR interpretation particularly difficult.

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“…The 8-line modulation superimposed on the broad resonance centred near geff 2 is due to VO 2+ (Pinnavaia et al, 1974;Hall et al, 1974;McBride, 1979;Monsef-Mirzai & McWhinnie, 1982). This modulation is more important for MILO (480 p.p.m.…”

Section: Esr Spectroscopymentioning

confidence: 99%

ESR and IR Evidence for Chromium in Kaolinites

Mosser¹,

Petit

Mestdagh

1993

Clay miner.

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Evidence obtained from ESR and IR studies is presented for the presence of structural Cr in two natural kaolinites (MILO and GEY) formed in an hydrothermal environment in Sonoma County, California. The XRD patterns show a greater structural disorder for GEY than for MILO, but both have the usual hexagonal shapes as shown by TEM observations. On the basis of EDX analysis of different particles, GEY, on average, appears to be richer in Cr (2.1% Cr203) than MILO (0.6% Cr203). The presence of Fe oxide particles containing some Cr, Ni and V is also indicated by EDX analysis. By FT-IR observation, the octahedral Cr 3+ position was easily detected by a well resolved spectral feature at 3586 cm -1. The adsorbed Cr 3+ kaolinite (KMRXCR) presents no band at 3586 cm 1, but two other bands situated at 3527 and 3477 cm 1. The main features of the ESR spectra of these two kaolinites are a set of resonances near geff 4; a broad resonance centred near geff 2 with some modulations; and a set of resonances near gcffl. The broad resonance centred near geff 2 is interpreted as the free iron oxide signal with modulations due to VO 2+. The set of resonances near g~f~ 4 is similar to that observed for octahedral Fe 3+, but the position is shifted compared to that of octahedral Fe 3+. This set of resonances near geff 4 is, therefore, interpreted as belonging to Cr 3+ in octahedral position. The resonances at geff 1 are also interpreted as belonging to Cr 3-. Comparison with the Cr 3+ surface-adsorbed ESR signal of a Cr-saturated kaolinite (which is a broad resonance centred near geff 2) strengthens the interpretation of the geff 4 resonances belonging to Cr 3+ in the octahedral position. The results obtained by the combination of FT-IR and ESR spectroscopics indicate that Cr 3+ is present in the octahedral position of the MILO and GEY kaolinites.

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Electron spin resonance and related studies of lignite and ball clay from South Devon, England

Cited by 35 publications

References 24 publications

Electron spin resonance and distribution of some elements in shales

Electron spin resonance and distribution of some elements in shales

Preliminary Results of Petrographic and Electron-Spin-Resonance Studies of Organic Matter from Deep Sea Drilling Project Sites 370 and 416

ESR and IR Evidence for Chromium in Kaolinites

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