Within the context of deep crustal magnetic anomalies, and in the determination of Curie isotherms, it is proposed that the primary and secondary mineralogy of plutonic ultramafic rocks be carefully reevaluated based on current models of serpentinization. Metallic iron and metal alloys of Fe-Ni-Co-Cu are widely recognized in these rock types, and because these minerals have elevated Curie temperatures (620-1100oC) the depth detection limits of aeromagnetic anomalies need not be constrained by the accepted value of 580oC, the Curie temperature of magnetite.-Authors
