Electronic Heat Trap Grips Deep Earth: Current Models Of Mantle Dynamics Challenged

November 13, 2008

The key to understanding Earth’s evolution, including how our atmosphere gained oxygen and how volcanoes and earthquakes form, is to look deep, really deep, into the lower mantle—a region some 400 to 1,800 miles (660 to 2,900 kilometers) below the surface.

Researchers at the Carnegie Institution’s Geophysical Laboratory simulated conditions at these depths and recently discovered that the concentration of highly oxidized (ferric) iron (Fe3+) in the two major mantle minerals is key to moving heat in that region. Such heat transfer affects material movement throughout the planet. They also discovered that less oxidized (ferrous) iron (Fe2+) has much smaller effect than expected.

The results, reported in the November 13, issue of Nature, call into question current models of mantle dynamics.

The diamond anvil cell squeezes samples to inner-Earth pressures, between two diamond tips. (Credit: Image courtesy Alex Goncharov, Carnegie Institution)

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Posted in Earth Sciences, Science and Technology