Joint inversion of airborne magnetic and electromagnetic data: case study in the Northwest Territories of Canada

Abstract

One of the major challenges in interpretation of airborne geophysical data is the ability to jointly invert multiple geophysical datasets to self-consistent 3D earth models of physical properties that can subsequently be used for mapping the mineral deposits. In practice, empirical or statistical correlations between different physical properties may exist, but their specific forms may be unknown. In addition, there could be both analytical and structural correlations between different attributes of the model parameters. There is a need to develop joint inversion methodologies which would not require a priori knowledge about specific empirical or statistical relationships between the different physical parameters and/or their attributes. To this end, Zhdanov et al. (2012a) have recently developed a generalized theoretical framework for joint inversion using Gramian constraints. In this paper, we apply this general method to the solution of the problem of joint inversion of TMI and EM data. The case study of the joint inversion of airborne magnetic and electromagnetic data in the area of the Northwest Territories of Canada has demonstrated that joint inversion with Gramian constraints recovered the higher remanent magnetization typical of kimberlite pipes.