title: Carbon-Isotope Composition and the Origin of Calcareous Coal Balls.
abstract: The C(13):C(12) ratios of the carbonate comprising "normal," "faunal," and "mixed" coal balls are consistent with the hypothesis that calcareous coal balls contain varying proportions of two kinds of carbonate: (i) precipitated carbonate formed in the coal swamp and characteristically deficient in C(13), and (ii) extraneous detrital material, mainly fossil fragments relatively enriched in C(13).
authors.forename: J N
authors.initials: JN
authors.lastname: Weber
authors.forename: M L
authors.initials: ML
authors.lastname: Keith