Skip to Main Content
Book Chapter

Compositional characteristics and inferred origin of three Late Pennsylvanian coal beds from the northern Appalachian Basin

By
Cortland F. Eble
Cortland F. Eble
1
Kentucky Geological Survey, University of Kentucky, Lexington, Kentucky, USA
Search for other works by this author on:
William C. Grady
William C. Grady
2
West Virginia Geological and Economic Survey, Morgantown, West Virginia, USA
Search for other works by this author on:
Brenda S. Pierce
Brenda S. Pierce
3
U.S. Geological Survey, Reston, Virginia, USA
Search for other works by this author on:
Published:
January 01, 2006

The Pittsburgh, Redstone, and Sewickley coal beds all occur in the Late Pennsylvanian Pittsburgh Formation of the Monongahela Group in the northern Appalachian Basin. The goal of this study is to compare and contrast the palynology, petrography, and geochemistry of the three coals, specifically with regard to mire formation, and the resulting impacts on coal composition and occurrence. Comparisons between thick (>1.0 m) and thin (<0.3 m) columns of each coal bed are made as well to document any changes that occur between more central and more peripheral areas of the three paleomires.

The Pittsburgh coal bed, which is thick (>1m) and continuous over a very large area (over 17,800 km2), consists of a rider coal zone (several benches of coal intercalated with clastic partings) and a main coal. The main coal contains two widespread bone coal, fusain, and carbonaceous shale partings that divide it into three parts: the breast coal at the top, the brick coal in the middle, and the bottom coal at the base. Thymospora thiessenii, a type of tree fern spore, is exceptionally abundant in the Pittsburgh coal and serves to distinguish it palynologically from the Redstone and Sewickley coal beds. Higher percentages of Crassispora kosankei (produced by Sigillaria, a lycopod tree), gymnosperm pollen, and inertinite are found in association with one of the extensive partings, but not in the other. There is little compositional difference between the thin and thick Pittsburgh columns that were analyzed.

The Redstone coal bed is co-dominated by tree fern and calamite spores and contains no Thymospora thiessenii. Rather, Laevigatosporites minimus, Punctatisporites minutus, and Punctatisporites parvipunctatus are the most common tree fern representatives in the Redstone coal. Endosporites globiformis, which does not occur in the Pittsburgh coal, is commonly found near the base of the coal bed, and in and around inorganic partings. In this respect, Endosporites mimics the distribution of Crassispora kosankei in the Pittsburgh coal. Small fern spores are also more abundant in the Redstone coal bed than they are in the Pittsburgh coal. Overall, the Redstone coal bed contains more vitrinite, ash, and sulfur than the Pittsburgh coal. The distribution of the Redstone coal is much more podlike, indicating strong paleotopographic control on its development. Compositionally, there are major differences between the thin and thick Redstone columns, with higher amounts of Endosporites globiformis, gymnosperm pollen, inertinite, ash, and sulfur occurring in the thin column.

The Sewickley coal bed is palynologically similar to the Redstone coal in that it is co-dominated by tree fern and calamite spores, with elevated percentages of small fern spores. Tree fern species distribution is different, however, with Thymospora thiessenii and T. pseudothiessenii being more prevalent in the Sewickley. The distribution of Crassispora kosankei in the Sewickley coal bed is similar to that in the Pittsburgh coal, i.e., more abundant at the base of the bed and around inorganic partings. By contrast, Endosporites is only rarely seen in the Sewickley coal. The Sewickley is more laterally continuous than the Redstone coal, but not nearly as thick and continuous as the Pittsburgh coal. Overall, the vitrinite content of the Sewickley coal is between that of the Pittsburgh (lowest) and Redstone (highest). Ash yields and sulfur contents are typically higher than in the Pittsburgh or Redstone. The thin and thick Sewickley columns are palynologically and petrographically very similar; ash and sulfur are both higher in the thin column.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Special Papers

Wetlands through Time

Stephen F. Greb
Stephen F. Greb
Search for other works by this author on:
William A. DiMichele
William A. DiMichele
Search for other works by this author on:
Geological Society of America
Volume
399
ISBN print:
9780813723990
Publication date:
January 01, 2006

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal