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Organic metamorphism

Two points must be taken into account in the present context. Too often kerogen is considered to be a single entity while in fact it is an assemblage of many entities representing different preservational conditions. It must also be taken into account that organic metamorphism in mineral grains cannot be fully compared with [Pg.19]

Infrared and Raman spectrophotometry have become established as worthwile tools in the study of metamorphosed chemofossils. The spectra show which functional groups predominate in immature kerogen and what changes occur during maturation (Fig. 15). [Pg.21]

The metamorphic alteration of hydrocarbon structural units has been studied by Robin et al. (1977) 21), who documented the expected disappearance of aliphatic C—H bonds with increasing levels of maturity, and also demonstrated the disappearance of aromatic C—H bonds as structures approach extreme levels of carbonization. In extreme cases when the carbon content exceeds 91 % by weight and the H/C atomic ratio is only 0.4, aliphatic and G=0 bonds have vanished, and aromatic C=C are the main components remaining in IR spectra. The [Pg.21]

Brown (1955)611 has studied the IR spectra of coals with special attention on the optical densities of the two peaks at 3030 and 2920 cm-1. He found that the ratio of aromatic hydrogen to total hydrogen increased with rank. Fujii and his collegues (1970)62) noted that the absorption band at 2920 cm-1 generally increased with rank to 86% carbon but thereafter decreased sharply with higher carbon contents. [Pg.22]

Comparison of the available Laser mass spectra shows, that the portion of hydrogen contained in the recorded carbon clusters becomes gradually smaller with increasing rank of the carbonaceous matter (see Figs. 39, p. 49). These are preliminary results which need to be studied in more detail. [Pg.22]


HOOD (A.), GUTJAHR (C.C.M.) and HEACOCK (R.L.), 1975. Organic metamorphism and the generation of petroleum. Amer. Assoc. Petrol. Geol. [Pg.197]

Evans, C. R., Regional Facies of Organic Metamorphism, Third Inter-... [Pg.34]

Staplin, F. L., Sedimentary Organic Matter, Organic Metamorphism,... [Pg.60]

Gretener P. E. and Curtis C. D. (1982) Role of temperature and time on organic metamorphism. AAPG Bull. 66, 1124-1149. [Pg.3682]

Staplin F. L. (1969) Sedimentary organic matter, organic metamorphism, and oil and gas occurrence. Can. Petrol. Geol. Bull. 17(1), 47-66. [Pg.3719]

Price L. C. (1983) Geologic time as a parameter in organic metamorphism and vitrinite reflectance as an absolute paleogeothermometer. J. Petrol. Geol. 6, 5-38. [Pg.3978]

Price L. C. (2000) Organic metamorphism in the California petroleum basins Chapter B. Insights from extractable bitumen and saturated hydrocarbons. US Geol. Surv. Bull. B2174-B, 33pp. [Pg.3978]

Schopf J. W., Kudryavtsev A. B., Agresti D. G., Czaia A. D. and Wdowiak T. J. (2002a) Laser-Raman chemistry and organic metamorphism of Precambrian microscopic fossils. Eos. Trans. Am. Geophys. Union 83(19), S372-S373 (Abstract). [Pg.375]

Subbituminous coal that has been subjected to an increased level of organic metamorphism, which has driven off some of the oxygen and hydrogen in the coal. That loss produces coal with higher carbon content (71%-77% on a dry ash-free basis). Subbituminous coal has a heating value between 8,300 and 13,000 Btu/lb on a mineral matter-free basis. On the basis of heating value, it is subdivided into subbituminous A, subbituminous B, and subbituminous C ranks. [Pg.61]

Coal is also considered (perhaps without sufficient scientific foundation) to be a metamorphic rock—the result of heat and pressure on organic sediments such as peat—but most sedimentary rocks undergo some heat and pressure and the association of coal with typical sedimentary rocks and its mode of formation usually keep low-grade coal in the sedimentary classification system. On the other hand, anthracite, on the other hand, undergoes more heat and pressure and is associated with low-grade metamorphic rocks and is justifiably considered to be an organic metamorphic rock. [Pg.103]

The thermal maturity of a rock is a measure of the degree to which organic metamorphous has progressed. It gives a crude indication of the maximum temperature the rock has experienced. [Pg.69]

Soil is a mixture of solid materials, air and, usually, water and organic matter. The radium content of soil often reflects that of the rocks from which the solid materials are derived by physical and chemical activity. The observed ranges are from 0 to 20 Bq kg for ultrabasic rocks (dunite) to 1 to 1835 Bq kg for igneous metamorphic rocks (gneiss) (Wollenberg, 1984). While these ranges are broader than those for measured for soils, the mean values for rocks, excluding alkali rocks, is consistent with the means observed for soils. [Pg.17]

Kitchen NE, Valley JW (1995) Carbon isotope thermometry in marbles of the Adirondack Mountains, New York. J metamorphic Geol 13 577-594 Kiyosu Y, Krouse HR (1990) The role of organic acid in the abiogenic reduction of sulfate and the sulfur isotope effect. Geochem J 24 21-27... [Pg.253]


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See also in sourсe #XX -- [ Pg.159 ]




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