A method for curvilinear structure mapping in normalized derivative magnetic maps

Abstract

Enhancement techniques are frequently applied on magnetic field maps to facilitate the interpretation of geological units and structures. Among them, the normalized derivative (ND) approach represents a class of techniques specifically designed to balance weak and strong anomalies (Fairhead and Williams, 2006). In this paper, we present an approach for the enhancement, detection and mapping of curvilinear structures in ND magnetic maps. The proposed approach locates ridges and valleys in ND maps using multiscale Hessian analysis and filtering, non-maxima suppression and morphological thinning with anchor points. The efficiency of the method is demonstrated on four different magnetic map subsets with differing geological settings. A practical application of the method is demonstrated using the magnetic maps from the Tehery Lake – Wager Bay region of Nunavut, Canada. Geological features are effectively defined, highlighting near surface structures and key units that are important for understanding the mineral potential of the region.