Sulfur variability and petrology of the Lower Block Coal Member (Pennsylvanian) in Southwest Indiana

Penny L. Padgett, Susan M. Rimmer, John C. Ferm, James C. Hower, Cortland F. Eble, Maria Mastalerz

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The Lower Block Coal Member (Pennsylvanian-Atokan, Westphalian C) is an economic low-to medium-sulfur, low-ash coal resource in the Illinois Basin. Sulfur content is generally low (averaging 1.0%) in the study area, but varies over short distances. Higher sulfur areas occur as isolated pods and epigenetic pyrite increases significantly in the upper third of the selected columns in higher sulfur areas. Sulfur variations cannot be predicted by typical geologic characteristics such as roof lithology, seam thickness, or seam elevation. Petrographic analysis shows that pyrite is generally associated with brighter microlithotypes, except in higher sulfur areas where infilling pyrite forms are associated with inertite. Higher sulfur areas reflect the water chemistry of the paleomire during and shortly after peat accumulation. Locally, abundant pyrofusinite provided additional pore space for pyrite precipitation.

Original languageEnglish
Pages (from-to)97-120
Number of pages24
JournalInternational Journal of Coal Geology
Issue number1-3
StatePublished - Mar 1999

Bibliographical note

Funding Information:
Financial support for this study was provided by the Geological Society of America Coal Division Medlin Scholarship Fund and the Geological Society of America Grants-In-Aid Research Fund. We would like to thank Solar Sources, Phoenix Natural Resources, United Minerals, and MAPCO Coal for providing access to the mines and computer software support; with special thanks to Matt Atkinson, Mike Owen, Ernie Seib, Ray Jones, Scott Scuhle, Ray Judy, Tony Gray, Bobby Dyer, and John Popp. This study would not have been possible without the support of the Kentucky Geological Survey, who provided the facilities to analyze the samples, the Indiana Geological Survey, and McCoy and McCoy Laboratories. Specifically, we wish to thank Jim Cobb, Mark Thompson, Henry Francis, Jerry Weisenfluh, Ernie Thacker, Norman Hester, Erik Kvale, Carl Rexroad, John Rupp, and Ama Bowen.


  • Coal
  • Illinois Basin
  • Indiana
  • Low-sulfur coal
  • Lower Block Coal
  • Pyrite
  • Sulfur

ASJC Scopus subject areas

  • Fuel Technology
  • Geology
  • Economic Geology
  • Stratigraphy


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