||Helton, Erica L.; Bell, John W.; Cashman, Patricia H.; Lazaro, Michael; Alm, Steve
||Dixie Valley; Nevada; Geothermal; LiDAR; Low-sun-angle aerial photography
||Geothermal Resources Council Transactions
||Exploration; Remote sensing; Geological surveys
||The goal of this study is to map and characterize Quaternary faults in southern Dixie Valley for the Department of the Navy Geothermal Program Office’s NAS Fallon Geothermal Exploration Project. We will use this information to better characterize the regional structure and geothermal resource potential of the area, with a focus on determining the structural controls for two known geothermal anomalies. Previous structural investigations at other geothermal sites in Nevada have shown that Quaternary faults provide the best potential for geothermal fluid flow. Information on the structural characteristics, such as slip sense and relative age, will be synthesized into a structural kinematic model. The resulting structural kinematic model will help us identify the slip and dilation tendencies of the faults in southern Dixie Valley. This model will for allow a better understanding of what faults control these two geothermal anomalies and aid in exploration and selection of drilling targets. In order to detect and characterize young faults, high resolution LiDAR and 1:12,000-scale low-sun-angle (LSA) aerial photography was acquired for the NAS Fallon study area. The LSA photos were flown during early morning, when the sun angle ranged between 10-25°. Slopeshades and hillshades using low sun angles (25-45°) were generated using LiDAR for fault detection. Elevation change and tonal lineaments were used to define possible faults in both the LiDAR and LSA photo data sets. The LiDAR and LSA photo analysis has identified a large number of previously unmapped faults. Field investigations will determine slip sense and age of these newly mapped faults. Preliminary structural analysis using the newly mapped faults, in conjunction with shallow 2-meter temperature surveys, suggests that the two known geothermal temperature anomalies occur in complex structural settings. A possible 3rd low temperature anomaly was also detected, but will require further investigation.