f Inversion of HEM data for resistivity and susceptibility

An algorithm has been developed for processing helicopter electromagetic (HEM) data for mapping both conductivity and permeability variations in the earth. The motivation behind its development was to correct HEM resistivity maps for the presence of magnetite in a gold prospect in northern Norway, and to use those corrections to produce susceptibility maps from the electromagnetic data. Gold in this area is known to be associated with breaks in graphitic conductors which are often associated with oxidation of graphitic schist and magnetite in the adjacent metadiabase.