Geomagnetic excursion

A polarity excursion, even geomagnetic excursion, is a significant change in the prevailing geometry of the geomagnetic field, which lasts less than 1000 years. It is also different polarity events (also called Subchron ), with a life of 10,000 to 100,000 years ago, where a complete reversal of polarity of the Earth's magnetic field is carried out, but this is not permanent, as well as the polarity change (also Chron ), in which the field reversal of time is. A Chron takes a while to 100,000 to 1,000,000 years.

The global impact of these events, they are an important means of stratigraphy; they do serve to associate an age geological formations and to correlate with other rock sequences. The branch of stratigraphy that deals with the changes of the Earth's magnetic field is called the magnetostratigraphy.

The cause of the change in the Earth's magnetic field is nowadays attributed to local perturbations of the convection currents in the outer mantle.