The Rome Trough in Pennsylvania: Speculation in the Absence of Non-Proprietary Seismic Data

Harper, John A.
Pennsylvania Geological Survey, Pittsburgh, PA 

Extensional basement faulting in western and north-central Pennsylvania has been known for several decades from proprietary seismic surveys. It consists primarily of down-to-the-east/southeast normal faults, although down-to-the-west/northwest faults also occur, forming the Pennsylvania portion of the Rome trough. The trough complex is well known in Kentucky and southern West Virginia, but the lack of non-proprietary seismic data in Pennsylvania has led some to speculate that it is subdued or non-existent to the north. In the absence of non-proprietary data, the Rome trough is best defined in Pennsylvania by a variety of published and open-file geophysical, geological, and geomorphologic evidence. For example, a basement fault or fault system, possibly the western edge of the trough, acted as a hinge throughout the Phanerozoic that, at least subtlety, affected depositional patterns, structural fabric, drainage, and emplacement of economic deposits. This hinge separated the western, relatively stable cratonic portion of the basin from the eastern, rapidly subsiding geosyncline.

Although most geologists accept the existence of the Rome trough in Pennsylvania, there is still some controversy as to exactly WHERE it occurs. Most published reports describe it as an arcuate graben trending uninterruptedly southwest (Greene County) to northeast (Potter County). An alternate view has it trending roughly east-northeast out of West Virginia into central Pennsylvania. Available geophysical and geological data suggest the trough trends in an arcuate band from southwestern to north-central Pennsylvania, and is segmented and offset by numerous basement wrench faults – transform faults associated with the rifting episode.

AAPG Search and Discovery Article #90031©2004 AAPG Eastern Section Meeting, Columbus, Ohio, October 3-5, 2004