Evidence for Early Pennsylvanian Faulting in Eastern Kentucky Coalfield

Stephen F. Greb, Donald R. Chesnut, Jr., O. Barton Davidson, Rene Rodriguez

A series of sedimentary features including a mass-flow deposit and contorted pseudo-nodule layers at approximately the same stratigraphic horizon on the eastern, downthrown block of a normal fault system along the Rockcastle River in the Eastern Kentucky coalfield indicate that the fault was active during deposition of the Lee sandstone.

The rarity of mass flows in this part of the section, a change in paleocurrents compared with surrounding units, the abundant shale clasts indicating short transport distance, and the detrital siderite clasts within the flow that are abundant on the upthrown block of the fault and not in underlying sandstones on the downthrown block of the fault indicate that movement along the fault provided an upthrown source of sideritic shales and may have triggered the mass flow.

Several areas of slumping and contorted bedding also occur on the downthrown side of the fault. Of particular interest are two shaly units containing isolated and contorted sandstone pseudonodules or pillows. The sandstones are tightly folded but exhibit no apparent preferred orientation of folding or horizontal translation. These deposits are also unique to this area in the coalfield and coupled with their location near the fault may indicate that liquefication of sand and shale layers was the result of seismic energy from the nearby fault.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.