geomagnetic reversal

geomagnetic reversal
Alternation of the Earth's magnetic polarity.

The Earth's internal magnetic field reverses, on average, about every 300,000 to 1 million years. This reversal is very sudden on a geologic time scale, apparently taking about 5,000 years. The time between reversals is highly variable, sometimes less than 40,000 years and at other times as long as 35 million years. No regularities or periodicities have yet been discovered. A long interval of one polarity may be followed by a short interval of opposite polarity. See also polar wandering.

* * *

      an alternation of the Earth's magnetic polarity in geologic time. See polar wandering.

* * *


Universalium. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Geomagnetic reversal — Magnetic reversal redirects here. For switching of a magnet, see Magnetization reversal. Geomagnetic polarity during the late Cenozoic Era. Dark areas denote periods where the polarity matches today s polarity, light areas denote periods where… …   Wikipedia

  • Geomagnetic pole — Illustration of the difference between geomagnetic poles (Nm and Sm) and geographical poles (Ng and Sg). The geomagnetic poles are antipodal points where the axis of a theoretical dipole intersects the Earth s surface. This dipole is equivalent… …   Wikipedia

  • geomagnetic field — Magnetic field associated with the Earth. It is essentially dipolar (i.e., it has two poles, the northern and southern magnetic poles) on the Earth s surface. Away from the surface, the field becomes distorted. Most geomagnetists explain the… …   Universalium

  • Geomagnetic excursion — A geomagnetic excursion, like a geomagnetic reversal, is a significant change in the Earth s magnetic field. Unlike reversals however, an excursion does not change the large scale orientation of the field, but rather represents a dramatic,… …   Wikipedia

  • Geomagnetic storm — This article is about disturbances within Earth s magnetosphere. For other uses of magnetic storm , see Magnetic storm (disambiguation). Solar particles interact with Earth s magnetosphere. A geomagnetic storm is a temporary disturbance of the… …   Wikipedia

  • Brunhes-Matuyama reversal — The Brunhes Matuyama Reversal was a geologic event, approximately 780,000 years ago, when the Earth s magnetic field last underwent reversal. The reversal occurred over several thousand years. The apparent duration at any particular location… …   Wikipedia

  • Gauss-Matuyama reversal — The Gauss Matuyama Reversal was a geologic event approximately 2.588 million years ago when the Earth s magnetic field underwent reversal.This event, which separates the Piacenzian from the Gelasian and marks the start of the Quaternary… …   Wikipedia

  • Jaramillo reversal — The Jaramillo reversal was a reversal of the Earth s magnetic field that occurred approximately one million years ago. In the geological time scale it was a short term positive reversal in the then dominant Matuyama reversed magnetic chronozone;… …   Wikipedia

  • 2012 phenomenon — Part of a series on …   Wikipedia

  • Earth's magnetic field — Computer simulation of the Earth s field in a normal period between reversals.[1] The tubes represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”