Science News

For years, many scientists had thought that plate tectonics existed nowhere in our solar system but on Earth.

The Earth's magnetic field has reversed many times at an irregular rate throughout its history. Long periods without reversal have been interspersed with eras of frequent reversals. What is the reason for these reversals and their irregularity? Researchers from CNRS and the Institut de Physique du Globe, France, have shed new light on the issue by demonstrating that, over the last 300 million years, reversal frequency has depended on the distribution of tectonic plates on the surface of the globe. This result does not imply that terrestrial plates themselves trigger the switch over of the magnetic field. Instead, it establishes that although the reversal phenomenon takes place, in fine, within the Earth's liquid core, it is nevertheless sensitive to what happens outside the core and more specifically in the Earth's mantle. This work is published on 16 October 2011 in Geophysical Research Letters.

(PhysOrg.com) -- Plate tectonics in its current form is believed to have started one billion years ago.