Relations of jointing to orientation of solution cavities in limestones of central Pennsylvania

Abstract

Twenty-six caves in central Pennsylvania were divided into passage segments inferred to have formed along the strike of fracture planes. For each cave passage, bearings weighted by footage were used to calculate an average passage orientation. Fractures measured at outcrops near the caves were classed by strike of subparallel sets which were cumulated by frequency for preferred orientations. Average passage orientation compared with orientation of fracture frequency was significant to the 95 percent level. Thus, caves develop more footage parallel to the strike of the more abundant fractures. Solution passages can therefore be used as one determinant of the local fracture system, and a selective solution process may be related to the mechanical origin of the fractures as well as their frequency.