GEOPHYSICAL INVESTIGATION OF THE TUCSON MOUNTAINS

Abstract

Transient Electromagnetic (TEM), Controlled Source Audio Magnetotellurics (CSAMT), Gravity, and Magnetic data were collected in the Tucson Mountains during the Spring semester, 2011. The goal was to investigate the extent of a low-resistivity porous sedimentary layer and faults that may form potential traps located under the surface volcanic layers, as interpreted by Lipman 1993. The sedimentary layer under the volcanics has the potential to be used for either water resources or compressed air storage to store solar energy. The results from the TEM and CSAMT surveys broadly correlated with the thickness of the volcanic layer and throw of the faults interpreted by Lipman, 1993. The gravity modeling suggested the faults may have a larger throw than what was indicated by the other methods. Because of the fundamental uncertainty in the densities to use in the modeling, it was concluded that the gravity modeling may not give as accurate a prediction of the structure in this region. For further investigation of the deep porous sedimentary layer, we suggest that TEM and CSAMT are the most effective methods.