Reversals in the Earth’s magnetic field are believed to result from instability that develops within the outer core geodynamo. To understand this process and to predict how the Earth system would respond to a future reversal, it is critical to map out a detailed description of the global geomagnetic field that occurs during the transition …
During the past 50 years, field measurements of sea-floor magnetic anomalies combined with paleomagnetic studies of volcanic and sedimentary sequences have yielded the construction of the geomagnetic polarity time scale. Excursions represent periods during which the magnetic pole deviates by more than 40° away from the geographic pole.
Geological processes tend to be slow. But in 1995 a discovery by a group of scientists shocked the world when they announced they had found evidence of a rapid geomagnetic reversal. Before then, geophysicists believed that a complete flip would take around 5000 years.
