Petrology of the River Gem coal bed, Whitley County, Kentucky

James C. Hower, James D. Pollock

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


The River Gem coal bed (Middle Pennsylvanian Breathitt Formation) in the Hollyhill 7 1 2 minute quadrangle, Whitley County, Kentucky, consists of a low- to moderate-sulfur lower bench; followed by a high-ash, high-sulfur bone; and capped by a high-ash, high-sulfur upper bench. Variations in the amount of total sulfur and pyritic sulfur as well as variations in the pyrite size and form point to the degree of syngenetic and epigenetic control on the pyrite emplacement. The pyrite types, particularly in the high-sulfur upper benches, are dominated by <10 μm fine forms. One of the fine forms, described as "specular" pyrite, is distinct from the framboidal and euhedral forms. "Specular" pyrite occurs as noncontiguous, submicron grains in corpocollinite within a clarite to carbargillite microlithotype and is particularly abundant in the bone lithotype. Epigenetic massive pyrite occurs as overgrowths of clusters of framboidal and euhedral pyrite as well as encasement of the cluster overgrowths. Split coal at one site and the apparent nondeposition of the upper bench at another site indicate that subsidence rates were variable at the time of deposition.

Original languageEnglish
Pages (from-to)227-245
Number of pages19
JournalInternational Journal of Coal Geology
Issue number3-4
StatePublished - May 1989

ASJC Scopus subject areas

  • Fuel Technology
  • Geology
  • Economic Geology
  • Stratigraphy


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