Fluviolacustrine Deposition in Hazard No. 8 to Hazard No. 8 Rider Seam Interval, Breathitt Formation (Pennsylvanian), Eastern Kentucky

Stephen F. Greb

The Hazard No. 8 (Francis) coal seam is a low-sulfur, low-ash coal of the Pennsylvanian Breathitt Formation in the south-central part of the Eastern Kentucky coalfield. Hazard No. 8 rider seams, which occur between 3 and 16 m above the main seam, are generally higher in both sulfur and ash content. Analyses of drill cores, contour-strip bench sections, and subsurface roof and pillar data were used to delineate nine lithofacies in the sequence of strata between the coal seams.

Facies analysis indicates that sediments in the interval were deposited along freshwater, flood-basin lakes between active fluvial channels that sporadically introduced detrital clastics into the swamps through crevasse-splay, overbank-flood, and channel-switching mechanisms. Some channels exhibit superpositional characteristics inferred to have been caused by crevasse-channel maintenance or possibly by confinement of channeling between ombrogenous peats.

Cessation of peat accumulation was accompanied by infilling of the flood-basin lakes by increasingly higher energy sedimentation systems. Stable conditions for peat accumulation were intermittently maintained during formation of the Hazard No. 8 rider coals, but ended with the onset of increasingly marine conditions.

AAPG Search and Discovery Article #91031©1988 AAPG Eastern Section, Charleston, West Virginia, 13-16 September 1988.