Removing varying directional trends in aeromagnetic data

• Pilkington, Mark
;
• Roest, Walter R.

Abstract

Both qualitative and quantitative interpretations of aeromagnetic data can be hindered by the presence of magnetic anomalies caused by mafic dykes. Such anomalies obscure the magnetic signatures due to basement lithology and structure, and their effects will often dominate when automated interpretation methods are applied to gridded data sets. Since dyke swarms are often nonparallel, simple frequencydomain strikesensitive filtering based on a single directional trend is not a viable method for removing their signatures. We use a coordinate transformation to project anomalies of various strikes onto one direction, which is then suppressed using a standard decorrugation method. The resulting grid is subsequently transformed back to the original projection. This approach is illustrated by the removal of the magnetic signature of the Proterozoic Mackenzie dyke swarm occurring in the Slave structural province, Northwest Territories, Canada.