IMPLICATION OF FRACTURE PATTERNS WITHIN LIMESTONES OF THE LATE PENNSYLVANIAN CONEMAUGH GROUP IN SOUTHEAST OHIO

Previous studies of fracture patterns in the Appalachian foreland basin have focused on strata at the orogenic front such that stresses at the distal margin of the basin are largely unresolved. This study builds on previous work in southeast Ohio by utilizing competent lithologies to add resolution to stress orientations and to extend the upper and lower stratigraphic limits of the data set within the Pennsylvanian Conemaugh Group. The collection of a large data set in a small area not only allows resolution at a local scale, but also helps to eliminate bias imposed by the orientation of the available outcrops.

The results of this study support the results of previous local studies and extend the data set from the Upper Brush Creek limestone to the Upper Pittsburgh limestone. Two dominant trends about 70^o apart can be noted from this interval. The first is oriented approximately N-S (350^o-000^o) and the second at 055^o-065^o. Three minor orientations also occur at 310^o-320^o, 010^o-020^o and 080^o-090^o. This contrasts somewhat with previous results, in which N-S set is a minor trend and the 040^o-050^o set is more pronounced. However, the data support interpretations that one set lies parallel to the regional Appalachian fold axis orientation (longitudinal joints), while the other lies parallel to the principle stress in the region. Collectively, the data compiled in southeast Ohio can be used to model local structures and has implications for the regional Alleghanian orogenic pattern. The compilation may also help to model fluid migration through the Conemaugh Group.