TRACING DEEP STRUCTURE: SOIL GAS ANALYSES IN THE FINGER LAKES REGION OF THE APPALACHIAN PLATEAU, NYS

The Finger Lakes region of the Appalachian Plateau is currently a target for gas exploration along faults that affect the Ordovician Trenton-Black River section. The location of these faults is controlled by structures in the Precambrian basement. We conducted soil gas analyses along a NS transect to determine if the deep structures were associated with abnormally high concentrations of methane and ethane in shallow soil gas. The work is based upon the concept that thermogenic gas will seep upwards on fractures, resulting in higher abundances in overlying soil. The results of over 3000 soil gas analyses correlate extremely well with studies of fractures in outcrops, reported by Lugert and others. Narrow zones in which anomalously high methane and ethane concentrations (ethane indicates the gas is thermogenic, not biogenic) were found along strike with zones of intense fracturing (FIDs) mapped by Lugert and others along the shore of Seneca Lake. This suggests that the fractures are controlling the concentrations of soil gas, as we hypothesized. Correlation of our results, the fracture mapping, major lineaments, aeromagnetics and structures observed on a proprietary seismic line suggest that the soil gas anomalies can be correlated with deep structure.