FRACTURE ANALYSIS OF THE ELK MOUNTAIN SANDSTONE OF THE CATSKILL FORMATION, SOUTH ABINGTON AND SCOTT TOWNSHIPS, PENNSYLVANIA

Bedrock geology peripheral to the Wyoming Valley and in the vicinity of Waverly, PA contains numerous fractures and joints. Low primary permeability in competent Catskill Formation bedrock imposes a major role on joints in governing groundwater flow paths. An analysis of joint orientation was undertaken in order to characterize the structural grain of jointing and associated groundwater pathways. The study included 1) field reconnaissance and identification of optimum bedrock exposures, 2) measurement of joint attitudes and locations using a Brunton compass and GPS, 3) characterization of the jointed bedrock geology and 4) trend analysis of the joint measurements. Over one hundred and twenty trend measurements were taken on planar to subplanar joint surfaces perpendicular to horizontal and subhorizontal bedding planes at four field sites. Measurement data were analyzed for trends using standard statistical techniques and commercial software. The results indicate a pronounced northerly trend (resultant value of 1 degree) and minor E-W and N-NW trends. Joint trends are largely consistent with Alleghanian deformation and serve to identify principle groundwater flow directions.