13C Nuclear magnetic resonance studies of kerogen from Cretaceous black shales thermally altered by basaltic intrusions and laboratory simulations

Dennis, L.W.; Maciel, Gary E.; Hatcher, Patrick G.; Simoneit, Bernd R.T.

doi:10.1016/0016-7037(82)90046-1

Cited by 75 publications

(33 citation statements)

References 13 publications

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“…As noted for aryl C, variations in the placement of the data sets on the heating temperature axis would be expected given the differences in heating treatments. The lack of formation of O-aryl C at 157 ppm for kerogen that contained little if any carbohydrate (Dennis et al, 1982) supports the proposal that the O-aryl C present in the sapwood heated to temperatures 5300 C was derived from the thermal alteration of cellulose.…”

Section: Nmr Errors and Observability Of C In The Samplessupporting

confidence: 72%

“…Given the dominance of aryl C in charred structures, the chemical changes associated with the charring process are often expressed in terms of the change in the proportion of aryl C. The accumulation of aryl C with increased heating temperatures followed a similar pattern to that observed during the heating of cellulose (Shafizadeh, 1984;Pastorova et al, 1994) and kerogen (Dennis et al, 1982) (Fig. 5a).…”

Section: Nmr Errors and Observability Of C In The Samplesmentioning

confidence: 85%

“…Some of the variation of the different data sets along the heating temperature axis undoubtedly arises from the variations in the length of exposure time at each temperature. In addition, the initial presence of aryl C in the sapwood used in this study and kerogen used by Dennis et al (1982) means that at least at the lower heating temperatures, the aryl C is a mixture of lignin/kerogen derived aryl C originally present in the samples and that produced by heating. Similar progressive increases in aryl C content with increasing heating were noted when samples of humic and fulvic acid (Almendros et al, 1990(Almendros et al, , 1992 and ryegrass leaves (Knicker et al, 1996) were heated for increasing durations at 350 C. Formation of furan-like materials in the O-aryl spectral region is evident for materials containing significant quantities of cellulose (Shafizadeh, 1984;Pastorova et al, 1994).…”

Section: Nmr Errors and Observability Of C In The Samplesmentioning

confidence: 99%

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Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Baldock

Smernik

2002

Organic Geochemistry

751

516

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The residues remaining after incomplete combustion of vegetation (char) can contribute significantly to the carbon content of soils. Char C is considered biologically inert relative to other forms of organic C in soils; however, the degree of biological inertness is likely to be a function of the extent that the combustion residues were altered during thermal treatment. The relationship between changes in chemical composition and biological inertness of char C created in the laboratory by heating Pinus resinosa sapwood to temperatures between 70 and 350 C was quantified. Heating at each temperature was maintained until the mass of the residual char material stabilised (AE 2%). Chemical composition of the chars was assessed by elemental analysis, solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The susceptibility of the heated sapwood to biological oxidation was quantified in a 120-day laboratory incubation. Thermal treatment at temperatures 5200 C induced significant variations in chemical composition. Changes in elemental contents and molar elemental ratios were consistent with an initial dehydration and the formation of unsaturated structures. The NMR and DRIFT data indicated that the changes in the chemical composition with increasing heating temperature included a conversion of O-alkyl C to aryl and O-aryl furan-like structures, consistent with results from work examining the chemical changes associated with thermal treatment of cellulose, the major component of wood. The chemical changes significantly reduced the ability of a microbial inoculum derived from decomposing Pinus resinosa wood to mineralise carbon contained in the charred samples. The C mineralisation rate constants decreased by an order of magnitude for wood heated to 5200 C. #

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Section: Nmr Errors and Observability Of C In The Samplessupporting

confidence: 72%

Section: Nmr Errors and Observability Of C In The Samplesmentioning

confidence: 85%

Section: Nmr Errors and Observability Of C In The Samplesmentioning

confidence: 99%

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Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Baldock

Smernik

2002

Organic Geochemistry

751

516

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“…Such difference spectra were obtained from equal-area scaled spectra, with no factor multiplication, thus the positive areas show only the material that predomina tes in the control sample when compared with that subjected to heating, and vice-versa. The re1ative increase in aromaticity and the concomitant loss of aliphatic material in the HA conform to the typical response to heating of geopolymers [23], whereas in the FA intense loss of oxygencontaining functional groups occurred, and the residual material was enriched in their alkyl ske1etal structures. The IR spectroscopy revealed additional details on the effects of heating.…”

Section: Resul Ts and Discussionmentioning

confidence: 94%

Solid state NMR studies of fire-induced changes in the structure of humic substances

Almendros

González-Vila

Martı́n

et al. 1992

Science of The Total Environment

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“…Contact aureoles in the vicinity of dolerite sills are reported by Hagelskamp (1988) to average three times the thickness of the intrusive body, while Rowsell and De Swardt (1976) found "some metamorphic effect" to persist over a distance of twice the width of the sill. Dennis et al (1982) measured changes in vitrinite reflectance at distances of one to two times the sill thickness, and Simoneit et al (1981) only to a distance of about half the sill thickness. In 1974, Connan et al (cited by Rowsell andDe Swardt, 1976) even showed for the northern Karoo, that sills, which are usually not very thick, did not cause any metamorphism at all.…”

Section: Discussionmentioning

confidence: 99%

Smectite-to-Illite Conversion in a Geothermally and Lithologically Complex Permian Sedimentary Sequence

Bühmann

1992

Clays and clay miner.

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Abstract--The <0.5-tzm fraction of 120 samples from a lithologically complex Permian sedimentary sequence, underlying dolerite intrusive sheets, has been characterized by means of X-ray diffraction to establish I/S compositions as a function of temperature, lithology and time duration. Illitization has been active over the entire 210 m depth range and the clay data reflect both the local pattern of contact metamorphism and the more regional trend of heat flow during burial. A continuum exists in the illite proportions of the illite/smectite interstratifications with increasing distance from the intrusive sheet ranging from R = 3 with less than 5% smectite via R = 2 and R = 1 to R = 0 with up to 70% smectite. In the mixed-lithology section, individual component layers in the I/S within similar distance levels, but between contrasting lithologies, appear to vary only within a very restricted compositional range. In the massive mudstone strata, however, more silty parts contain I/S of a higher degree of ordering and lower expandability. Calcite contents are reflected in a higher rate of chlorite formation, but not in the I/S composition. A satisfactory inverse correlation was found between percent smectite in I/S and vitrinite reflectance in the lithologically complex section. R = 1 interstratifications are associated with a maximum vitrinite reflectance of 1.07-1.29 and R > 1 phases with 1.93-2.7, indicating that time duration is not a controlling factor in the illitization process in this facies. R = 0 interstratifications are present in a massive mudstone/siltstone sequence situated furthest from the igneous intrusives, and display vitrinite reflectance values of 1.42-1.52. No satisfactory explanations for this finding can be offered.

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13C Nuclear magnetic resonance studies of kerogen from Cretaceous black shales thermally altered by basaltic intrusions and laboratory simulations

Cited by 75 publications

References 13 publications

Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Solid state NMR studies of fire-induced changes in the structure of humic substances

Smectite-to-Illite Conversion in a Geothermally and Lithologically Complex Permian Sedimentary Sequence

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