Self-organizing maps for pseudo-lithological classification of 3D airborne electromagnetic, gravity gradiometry and magnetic inversions

Abstract

To improve mineral exploration success, there is an accepted need to increase the ?discovery space? by exploring under cover and to greater depths using 3D geological modelling supported by multiple 3D geophysical inversions. To facilitate this approach, multi-sensor airborne platforms capable of simultaneously measuring electromagnetic, gravity, and magnetic data are now being deployed. The availability of data from such systems poses a significant challenge to the exploration geophysicist: How do you generate a shared earth model that satisfies all data? We address this with a case study from the Reid-Mahaffy test site in Ontario, demonstrating how multiple 3D inversions of MEGATEM time-domain electromagnetic, FALCON gravity gradiometry and TMI data can be analysed by the self-organizing maps (SOM) data mining approach to produce 3D pseudo-lithological models. The results of our analyses are shown to be in agreement with the known geology of the Reid-Mahaffy test site.