Notes on the origin of altered macerals in the Ragged Edge of the Pennsylvanian (Asturian) Herrin coalbed, Western Kentucky

Bruno Valentim, James C. Hower, Jennifer M.K. O'Keefe, Sandra Rodrigues, Joana Ribeiro, Alexandra Guedes

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8 Scopus citations


The Ragged Edge of the Herrin (Western Kentucky No. 11) coal bed has a variety of maceral textures and assemblages that do not fit in the conventional vitrinite and inertinite definitions as established by the International Committee for Coal & Organic Petrology. Within a narrow zone at the marine margin of the coalbed, the coal is brecciated and cemented by carbonate with some of the brecciated clasts metamorphosed to anthracite-level vitrinite reflectances. This is in contrast to the ambient high volatile C bituminous coal rank in the region. Low-rank peat-like textures are preserved in the clasts, suggesting that the metamorphism took place soon after deposition of the peat. Geochemical and mineralogical evidences suggest that the increase in reflectance was the consequence of the channeling of hydrothermal fluids through the breccia. The narrow zone of metamorphism and, further, the juxtaposition of breccia clasts of varying degrees of metamorphism suggest that the hydrothermal influx occurred at shallow depths of burial, perhaps shortly following deposition of the peat.

Original languageEnglish
Pages (from-to)24-40
Number of pages17
JournalInternational Journal of Coal Geology
StatePublished - Aug 1 2013

Bibliographical note

Funding Information:
The samples for the first study of the Ragged Edge of the Herrin coalbed were logged in on 25 August 1983. The results of that study were presented at the first meeting of The Society for Organic Petrology in 1984 and published as part of the collected papers of that conference as Hower et al. (1987) . In the 30 years of investigating this sequence throughout the Western Kentucky coalfield, we have been fortunate to be able to collaborate with a number of coal companies including Island Creek Coal and Pyro Coal, both defunct, and Alliance Coal. Our collaborators include Eric Trinkle (now Delaware Department of Natural Resources), Anne Graese (Illinois), Gary Neuder (Louisiana), Carol and Andy de Wet (Franklin & Marshall College), Sean Brennan (US Geological Survey), Steve Moshier (Wheaton College), Anne Raymond (Texas A&M), John Popp (Natural Resource Partners), Mike Shultz (EOG Resources), and Sue Rimmer (Southern Illinois University, Carbondale). Mike McClure (currently with Marshall Miller & Associates) supplied the core samples for the de Wet et al. (1997) study when he was employed by Island Creek Coal Co. The Portuguese authors would like to thank FEDER through the Program COMPETE, FCT project “PEst-OE/CTE/UI0039/201-UI 39” and Ciência 2007 Program.


  • Carbonate
  • Coal metamorphism
  • Geochemistry
  • Hydrothermal
  • Marine margin

ASJC Scopus subject areas

  • Fuel Technology
  • Geology
  • Economic Geology
  • Stratigraphy


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