Coal rank, determined from vitrinite maximum reflectance and from chemical rank parameters, increases from high volatile C bituminous in portions of the Eastern Kentucky coalfield to low volatile bituminous in Buchanan County, Virginia, and McDowell County, West Virginia, and then decreases significantly to the Dry Fork anticline, 20 km to the southeast. The latter rank decrease, as noted when rank data from individual coals is used across the fold (400-500 m structural relief), can be accounted for by post-tectonic coalification at a paleogeothermal gradient of about 40-45°C/km. Reflectance gradients decrease from about 0.09% Rmax /100 m in central Buchanan County, Virginia, to 0.06% Rmax/100 min southeastern Pike County, Kentucky, to 0.03% max/100 m and less among the high volatile A and B coals to the nortwest of Pike County. The reflectance gradients are likely an indication of a decrease in paleogeothermal gradient to the northwest. Depth of burial may have also decreased to the northwest. Northward-trending rank anomalies superimposed on the regional trend in Kentucky may have been caused by subtle changes in the geothermal gradients associated with basement discontinuities or, alternately, by a depth of burial not accounted for at present, perhaps under now-eroded thrust sheets.
|Number of pages||13|
|State||Published - 1991|
Bibliographical noteFunding Information:
Acknowledgements--Special thanks are extended to all of our colleagues who provided constructive criticism of our presentation at the 1988 Geological Society of America and Society for Organic Petrology meetings. We wish to acknowledge the assistance of sample acquisition of James C. Currens of the Kentucky Geological Survey and Don Pollock of the Center for Applied Energy Research. Alan E. Bland, formerly with the CAER, provided access to unpublished gravity data. Work at the Center for Applied Energy Research was funded by the Kentucky Energy Cabinet.
Copyright 2015 Elsevier B.V., All rights reserved.
- West Virginia
- coal rank
- vitrinite reflectance
ASJC Scopus subject areas
- Geochemistry and Petrology