COINCIDENCE OF FRACTURE INTENSIFICATION DOMAINS WITHIN TRENTON-BLACK RIVER FAULTING IN THE FINGER LAKES REGION, NEW YORK: PART II, CAYUGA LAKE

The western Finger Lakes region of the Appalachian Plateau has been a target for natural gas exploration along faults in the Ordovician Trenton-Black River section. The location of these faults is controlled by structures in the Precambrian basement. In order to determine if deep structures revealed in seismic data were represented in fractures in the overlying Devonian sediments, we measured fractures along a northwest-southeast transect that parallels the western shore of Cayuga Lake. We recorded nine characteristics for over 3000 fractures measured in the Catskill Delta sediments along the western shore of Cayuga Lake. We calculated the fracture frequency for each fracture set. These data indicate that fracture patterns vary systematically along the northwest-southeast trending transect. At the south end of the lakeshore, there is a predominance of NNW-striking master fractures and fracture intensification domains (FIDs) that trend parallel to the shoreline. In the central portion of the lakeshore, ENE-striking fractures increase in abundance, are more closely spaced and often occur as master fractures. FIDs increase in abundance and trend both ENE and NNW. In the northern part of the transect, NNW-striking fractures predominate as they do in the southern section. The location of these ENE-striking fractures is coincident with Landsat and aeromagnetic lineaments. The coincidence of the aeromagnetic lineaments with the fracture patterns suggests that the reactivation of the Trenton-Black River structures influenced fracture development in the Devonian section. This study also demonstrates that deep fault trends can be extrapolated away from the original seismic line along lineaments that have been groundtruthed by integration of fracture analysis and soil gas analysis.