Magnetic anomaly map of the world

Abstract

The Magnetic Anomaly Map of the World is the first global compilation of the wealth of magnetic anomaly information derived from more than 50 years of aeromagnetic surveys over land areas, research vessel magnetometer traverses at sea, and observations from Earth‐orbiting satellites, supplemented by anomaly values derived from oceanic crustal ages. This map will soon be published by the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the Commission for the Geological Map of the World, and will be publicly released at the July 2007 meeting of the International Union of Geodesy and Geophysics, in Perugia, Italy.Metamorphism, petrology, and redox state all have important effects on the magnetism of crustal materials. The magnetic anomalies represented on this map (Figure 1) originate primarily in igneous and metamorphic rocks, in the Earth's crust, and possibly in the uppermost mantle. Magnetic anomalies represent an estimate of the short‐wavelength (<2600 kilometer) fields associated with these parts of the Earth, after estimates of fields from other sources have been subtracted from the measured field magnitude.