FRACTURE INTENSIFICATION DOMAINS, LINEAMENTS AND FAULTS IN THE SKANEATELES LAKE REGION OF THE ALLEGHANIAN PLATEAU OF NEW YORK STATE

This study integrates surface structural data with topographic lineaments in order to locate faults and to determine if local changes in the stress field related to these faults caused the local fracture patterns to deviate from the regional fracturing pattern. The field area is located in central New York State and stretches from the western side of Skaneateles Lake to the eastern side of Otisco Lake. Previous fieldwork in the area (Trainer, 1932; Smith, 1935) recognized, but did not map, any faults. As a result, the longstanding convention that the Appalachian Basin is generally unfaulted was thought to apply to the eastern Finger Lakes region. However, aeromagnetic, gravity and Landsat lineaments suggested to Jacobi (2002) that faults might occur in the region. This study demonstrates that several faults do occur in the field area. The general structural model for the northern Appalachian Basin in New York State suggested by such geologists as Engelder and Geiser (1980) and Zhao and Jacobi (1997) indicated that early cross strike fractures in this region should strike NNW, and later cross-strike fractures should strike northerly. Fieldwork has shown that master fractures strike locally in other directions as well, such as ENE, E-W and NW. These local trends of the master fracture suggests that local stresses, resulting from faults, have a greater influence on the development of fractures in the area that the general models would suggest. Fracture and lineament data, collected using standard UB Rock Fracture Group protocols, suggest the location of possible fault surfaces. A N-S trending fault was recognized with down-dip slicken lines in the Tully Limestone near Borodino. FIDs, lineaments, and stratigraphic offsets in the same region suggest that this fault system extends along much of the eastern shore of Skaneateles Lake. The linear Borodino reef (Heckel, 1973) is located along the fault trend. The fault was thus also active during Tully deposition, since the fault controlled the growth of the reef, and since the Tully changes thickness across the fault system. Other probable fault trends include east-northeast striking reactivated Iapetan-opening fault systems indicated by master fractures coincident with lineaments.