Geochemistry of the blue gem coal bed, Knox county, Kentucky

James C. Hower, Susan M. Rimmer, Alan E. Bland

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


The Blue Gem coal bed (Middle Pennsylvanian Westphalian B, Breathitt Formation), has low-ash (with some sample sites having less than 1% ash) and low-sulfur contents through parts of Knox County, Kentucky. Most collection sites exhibit similar vertical elemental trends in ash geochemistry. The relatively high-ash (>1% ash) lower part of the bed displays enrichment in TiO2, Zr, Cr, V and Ni; Co, Zn, Rb and Mn show enrichment at some sites. A low-ash (<1% ash) middle part of the bed displays enrichment in Sr, Ba and CaO; Fe2O3 is enriched in samples with carbonate minerals. The upper part of the bed contains >1% ash and a relative enrichment in SiO2, K2O and Rb and a relative decrease in Cu, Ni, Co, Ba and Mn when compared to the middle part of the bed. Principal components analysis indicates that the samples with an ash content 0.63-1.0% show associations for Ni, Cu, Cr and Co. Samples with between 1.01-2.0% ash display strong element associations that suggest increased clastic sediment contributions (TiO2, Zr, K2O, Rb, SiO2). The low-ash content and the upwards decrease in trace concentrations both suggest that the Blue Gem peat swamp was ombrotrophic through at least a part of its geologic history.

Original languageEnglish
Pages (from-to)211-231
Number of pages21
JournalInternational Journal of Coal Geology
Issue number3-4
StatePublished - Sep 1991

Bibliographical note

Funding Information:
We wish to thank Charles Jones and William Jones, both formerly with the Center for Applied Energy Research (CAER), and Garry Wild (CAER) for their assistance in this study. Dr. Dal Swaine provided insight into the locale of trace elements in coal minerals. Research at the CAER was funded by the Kentucky Energy Cabinet, Commonwealth of Kentucky.

ASJC Scopus subject areas

  • Fuel Technology
  • Geology
  • Economic Geology
  • Stratigraphy


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