3D inversion modelling, integration, and visualization of airborne gravity, magnetic, and electromagnetic data: The Quest Project

Abstract

Airborne and ground gravity and magnetic data, and airborne time domain data have been inverted to recover 3D distributions of density, magnetic susceptibility and electrical conductivity over an area 390km x 460 km in central British Columbia. Large scale gravity and magnetic inversions were first carried out to estimate the regional models. Data for 10 subvolumes were corrected for the regional background, inverted, and merged into a final detailed model containing 32 million cells. The airborne EM data were down-sampled along the acquisition line, inverted with a 1D algorithm using a laterally parameterized method and the results stitched together to generate a 3D model. A conductance rule was used to estimate the depth of penetration and a late-time background conductivity map has also been produced for the survey area. The resulting models provide guidance to the regional structure and prospective geology and location of alteration and mineralization. The final density contrast, magnetic susceptibility, and conductivity models have been integrated into a Common Earth Model ready for 3D GIS analysis, interpretation, and integration with geologic, drill-hole, and other geophysical information. The resulting physical property models can be used to guide regional targeting and help design more detailed, follow-up data acquisition.