The Ivrea Zone as a model for the distribution of magnetization in the continental crust

Magnetic properties of the principal lithologies of the Ivrea Zone of northern Italy have been measured. Maficultramafic granulite facies rocks and amphibolites from the granulite‐amphibolite facies transition zone are highly magnetic with susceptibilities greater than 0.5 × 10−3 (cgs) saturation magnetization values greater than ∽ 90 × 10−3 emu/cm³ and Curie points between 570° and 580°C. The magnetic phase is magnetite. All other lithologies are moderately to weakly magnetic. The magnetic mafic granulites are thick and laterally continuous and, thus, would make an appropriate deep crustal source for long wavelength magnetic anomalies in regions typified by low to average geothermal gradients.