ANALYSIS OF PENNSYLVANIAN ROCKS OF THE CENTRAL APPALACHIAN BASIN
CHESNUT, Donald R., Jr., Kentucky Geological Survey, University of
Kentucky, Mining and Mineral Resources Building, University of
Kentucky, Lexington, Kentucky, 40506-0107

The Pennsylvanian rocks of the Central Appalachian Basin can be divided
into two lithologic units: the massive, quartzose sandstones of the Lee
Formation and the coal-bearing sandstones and shales of the Breathitt
Group. The Lee and Breathitt, mapped in Kentucky, have been informally
extended into Tennessee, Virginia, and West Virginia to simplify
nomenclature. The Lee Formation occurs at the expense of the coal-
bearing rocks of the Breathitt Group, and therefore the distribution of
the Lee controls coal resources.
	The Lee and Breathitt overlap the Early Pennsylvanian (the so-called
Mississippian-Pennsylvanian) unconformity surface to the northwest. The
Lee occurs in two forms: (1) as unconformity channel fills, and (2) as
large sandstone belts. Several deep channels within the regional
unconformity surface, filled with sandstones of the Lee have been
mapped. The largest volume of Lee sandstones, however, occurs as four
belt-shaped lenses within the lower part of the Breathitt. In ascending
order, these are the Warren Point, Sewanee, Bee Rock, and Corbin
Sandstone Members of the Lee. The sandstone belts trend southwest and
average about 80 kilometers in width. They appear to be largely wedged
between the dipping unconformity surface to the northwest and the
Breathitt lithologies to the southeast. The dominant crossbed direction
and paleogradient for the Lee sandstones is to the southwest, parallel
to the trend of the belts.
	Certain thick and extensive marine zones as well as sandstone members
of the Lee were used here to informally subdivide the thick Breathitt
Group into more useful units for basin analyses. The informal
formations of the Breathitt Group, in ascending order, are the
Pocahontas, Bottom Creek, Alvy Creek, Grundy, Pikeville, Hyden, Four
Corners, and the Princess.