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File:Magnetic Declination Chart for the International Geomagnetic Reference Field, 2005.pdf. Add languages. Page contents not supported in other languages.
The following is a list of geomagnetic reversals, showing the ages of the beginning and end of each period of normal polarity (where the polarity matches the current direction). Source for the last 83 million years: Cande and Kent, 1995. [1] Ages are in million years before present (mya).
The magnetic field of the Earth, and of other planets that have magnetic fields, is generated by dynamo action in which convection of molten iron in the planetary core generates electric currents which in turn give rise to magnetic fields. [15] In simulations of planetary dynamos, reversals often emerge spontaneously from the underlying dynamics.
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English: This is a world map of magnetic declination created by the National Geophysical Data Center at NOAA. Français : Carte mondiale de la déclinaison magnétique terrestre créé par le centre national des donnée géophysiques ( NGDC ) de l'agence américaine responsable de l'étude de l'océan et de l'atmosphère ( NOAA ).
Magnetic: Brunhes-Matuyama magnetic reversal. 4] Calabrian: 1.8 Vrica Section, Calabria, Italy Magnetic: Approximately 15 ka after the end of magnetic polarity chronozone C2n (Olduvai). Biologic: Immediately above extinction Discoaster brouweri .
The magnetic property most useful in stratigraphic work is the change in the direction of the remanent magnetization of the rocks, caused by reversals in the polarity of the Earth's magnetic field. The direction of the remnant magnetic polarity recorded in the stratigraphic sequence can be used as the basis for the subdivision of the sequence ...
A chronozone or chron is a unit in chronostratigraphy, defined by events such as geomagnetic reversals (magnetozones), or based on the presence of specific fossils (biozone or biochronozone). According to the International Commission on Stratigraphy , the term "chronozone" refers to the rocks formed during a particular time period, while "chron ...