Iron fused with magnesium: New discovery may explain composition of Earth's core

December 12, 2005

The outer core of the Earth, whose composition until now has been a mystery, may consist of an alloy of iron and magnesium. This discovery by an international team of scientists with members from Linköping University in Sweden, being published in the journal Physical Review Letters, is, among other things, a major step toward being able to predict earthquakes.

In theoretical and experimental studies under extremely high pressure, the team has succeeded in mixing iron and magnesium.

“To be able to model what happens in the interior of the Earth, we have to know the composition of the core,” says Igor Abrikosov, professor of theoretical physics at Linköping University in Sweden and one of the authors of the article being published in Friday’s issue of the journal.

In the Earth’s core the temperature (6,000 degrees C) and pressure (3 million times the pressure of the atmosphere) are so high that it can’t be studied experimentally. However, it is known that it is too light to consist solely of iron, and among other elements, silicone, sulfur, and oxygen have been proposed as being mixed in. On the other hand, magnesium has been excluded even though it is one of the Earth’s most common elements.

“It has been thought that iron and magnesium cannot be mixed in molten form, since the iron atomic volume is too small in relation to the magnesium atomic volume. But if we increase the pressure, the volume diminishes more rapidly in magnesium than in iron,” explains Igor Abrikosov.

The theoretical studies were followed up with a unique experiment in a so-called diamond anvil cell, which can withstand extremely high pressures. It turned out that it was possible to make alloys of iron and magnesium at pressures as low as 200,000 atmospheres.

The findings may also be of great significance in the search for new materials for industrial applications.

Other members of the team behind the article “Beating the miscibility barrier between iron and magnesium by high-pressure alloying” are L. Dubrovinsky, N. Dubrovinskaia , I. Kantor, W. A. Crichton, V. Dmitriev, V. Prakapenka, G. Shen, L. Vitos, R. Ahuja, and B. Johansson. The article is published in Physical Review Letters, vol. 95 no. 24.

Source: The Swedish Research Council

Explore further: Jupiter's moon Europa

Related Stories

Jupiter's moon Europa

September 30, 2015

Jupiter's four largest moons – aka. the Galilean moons, consisting of Io, Europa, Ganymede and Callisto – are nothing if not fascinating. Ever since their discovery over four centuries ago, these moons have been a source ...

A new kind of metal in the deep Earth

December 19, 2011

( -- The crushing pressures and intense temperatures in Earth's deep interior squeeze atoms and electrons so closely together that they interact very differently. With depth materials change. New experiments and ...

MAVEN results find Mars behaving like a rock star

June 22, 2015

If planets had personalities, Mars would be a rock star according to recent preliminary results from NASA's MAVEN spacecraft. Mars sports a "Mohawk" of escaping atmospheric particles at its poles, "wears" a layer of metal ...

Probing iron chemistry in the deep mantle

May 15, 2015

Carbonates are a group of minerals that contain the carbonate ion (CO32-) and a metal, such as iron or magnesium. Carbonates are important constituents of marine sediments and are heavily involved in the planet's deep carbon ...

Ten interesting facts about asteroids

February 3, 2015

At first glance, looking at a bunch of space rocks doesn't sound that exciting. Like, aren't they just a bunch of rubble? What use can they be in understanding the Solar System compared to looking at planets or moons?

Recommended for you

The dark side of Nobel prizewinning research

October 4, 2015

Think of the Nobel prizes and you think of groundbreaking research bettering mankind, but the awards have also honoured some quite unhumanitarian inventions such as chemical weapons, DDT and lobotomies.

Internet giants race to faster mobile news apps

October 4, 2015

US tech giants are turning to the news in their competition for mobile users, developing new, faster ways to deliver content, but the benefits for struggling media outlets remain unclear.

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Fusion reactors 'economically viable' say experts

October 2, 2015

Fusion reactors could become an economically viable means of generating electricity within a few decades, and policy makers should start planning to build them as a replacement for conventional nuclear power stations, according ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.