Quantitative 3D Modeling and Interpretation of High-Resolution Aeromagnetic Data Over Superstition Hills and Superstition Mountain, Imperial Valley, California

摘要

In November 2012, a high-resolution aeromagnetic survey was flown over the Naval Air Facility El Centro, California (NAFEC), to continue geothermal exploration of the Superstition Mountain and Superstition Hills. Data were collected by EDCON-PRJ, INC. and the inversion and analysis was performed by Wintermoon Geotechnologies, Inc. The analysis and interpretation indicated that granite and granodiorite bodies comprising Superstition Mountain have extremely low magnetic susceptibilities. The remainder of the survey area is underlain by basement of a much more iron-rich rock based on magnetic properties, suggesting a more mafic composition. Previous exploration using ground gravity at Superstition Mountain demonstrated a Northwest trending high gravity anomaly where there is a low in the aeromagnetic data. Also, previous mapping of acoustic basement and seismic activity are very similar to calculations of basement depth using the high resolution aeromagnetic data. When the aeromagnetic interpretations are compared to magnotelluric surveys (MT), self potential surveys (SP), and geophysical test hole drilling proximal to Superstition Mountain, data suggest that the high temperature anomaly on the northeast range front is controlled by northwest trending faults, however the heat does not seem to extend far perpendicular to strike. More recent exploration by the Navy Geothermal Program Office (GPO) has focused in the Superstition Hills area where interpretations from recently acquired LiDAR and aeromagnetic data suggest coincident geothermal exploration targets. These interpretations paired with 2-meter temperature probe data and relocated regional earthquake catalogues relative to mapped fault zones suggest certain areas within the Superstition Hills may have geothermal potential.