Calcite genesis in the Upper Freeport coal bed as indicated by stable isotope geochemistry

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6641100

Dulong, F T; Spiker, E C; Cecil, C B; Stanton, R W

The grinding and sizing in float-sink testing of the Upper Freeport coal bed physically separates calcite of different origins. The different origins are distinguished by different isotopic compositions. The isotopic compositions of calcite indicates at least two, possibly three, stages of calcite formation in the Upper Freeport coal bed. Calcite samples obtained from cleat, and isolated from 8x100 mesh-1.8 specific gravity sink fraction and -100 mesh size fraction, are enriched in /sup 13/C. The dispersion in /sup 18/O values for all three sample types, as measured by the standard deviation, is 2.7 per mil relative to SMOW, which may indicate similar temperature of formation. In contrast, calcite from the 1.275 specific gravity float fraction is depleted in /sup 13/C (mean = -4.6 per mil), indicative of CO/sub 2/ generated from the oxidation of organic matter. The standard deviation of /sup 18/O values for these samples is 9.2 per mil, probably indicating variation in the temperature of formation. Limestone samples associated with the Upper Freeport coal bed are slightly depleted in /sup 13/C (mean = -3.1 per mil). Genesis of calcite in the coal apparently resulted from biotic, as well as, thermogenic processes. A second stage of calcite formation, resulting from fermentation and methanogenesis is in cleat, and in the 8x100 mesh-1.8 specific gravity sink and -100 mesh size fractions. Part of the calcite in the 1.275 specific gravity float fraction may have formed from thermally generated CO/sub 2/ released during coalification.

• Research Organization: Geological Survey, Reston, VA (USA)
• OSTI ID: 6641100
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
58 GEOSCIENCES
COAL
CHEMICAL COMPOSITION
ISOTOPE RATIO
CALCITE
CARBON 13
COAL SEAMS
COALIFICATION
DENSITY
GEOCHEMISTRY
ORIGIN
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBON ISOTOPES
CARBONACEOUS MATERIALS
CARBONATE MINERALS
CARBONATES
CHEMISTRY
COAL DEPOSITS
ENERGY SOURCES
EVEN-ODD NUCLEI
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
ISOTOPES
LIGHT NUCLEI
MATERIALS
MINERAL RESOURCES
MINERALS
NUCLEI
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RESOURCES
STABLE ISOTOPES
010600* - Coal
Lignite
& Peat- Properties & Composition
580400 - Geochemistry- (-1989)