A Petrographic Evaluation of Environments of Accumulation of the Pocahontas No. 3 Coal Bed in Southwestern West Virginia

  1. C. Blaine Cecil,
  2. Cortland Eble,
  3. C. Blaine Cecil,
  4. James C. Cobb,
  5. Donald R. Chestnut Jr.,
  6. Heinz Damberger and
  7. Kenneth J. Englund
  1. William C. Grady

Published Online: 15 MAR 2013

DOI: 10.1029/FT143p0127

Carboniferous Geology of the Eastern United States

Carboniferous Geology of the Eastern United States

How to Cite

Grady, W. C. (1989) A Petrographic Evaluation of Environments of Accumulation of the Pocahontas No. 3 Coal Bed in Southwestern West Virginia, in Carboniferous Geology of the Eastern United States (eds C. B. Cecil, C. Eble, C. B. Cecil, J. C. Cobb, D. R. Chestnut, H. Damberger and K. J. Englund), American Geophysical Union, Washington, D. C.. doi: 10.1029/FT143p0127

Author Information

  1. West Virginia Geologic and Economic Survey, Morgantown, West Virginia

Publication History

  1. Published Online: 15 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875906478

Online ISBN: 9781118667316

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Keywords:

  • Low-ash yields;
  • Low-sulfur contents;
  • Petrographic composition;
  • Pocohontas No. 3 coal bed;
  • Southwestern West Virginia;
  • Sulfur variability

Summary

The Pocahontas No.3 coal bed in southeastern West Virginia ranges from 0 to 3 m (0 to 10 ft) in thickness, varies in ash from <2 percent to >30 percent, ranges in sulfur from 0.5 to 2.4 percent and, on average, contains 71.5 percent vitrinite (mean mineral-matter-free volume percent), 0 percent exinite and 28.2 percent inertinite.

Two layers were identified within the Pocahontas No. 3 coal bed that were laterally extensive and composed entirely of very intimately intermixed 10–20 micron size inertodetrinite, kaolinite and quartz. These layers account for much of the ash in the Pocahontas No. 3 coal bed.

Variations in thickness, ash-yield, sulfur-content and petrographic composition are attributable to differences in paleoenvironments of peat formation caused by contemporaneous folding which produced localized basins within the region of Pocahontas No. 3 paleo-peat swamp. In regions of localized subsidence, thicker peat developed which resulted in coal that is high in vitrinite and low in sulfur. The abundance of vitrinite is attributable to less oxidation of plant material. Outside of these, thinner peat accumulated, which resulted in coal that containes higher percentages of inertinite macerals, the result of increased oxidation.