Researchers unlock mystery of layer encircling the Earth's core

January 30, 2006
Earth from space

University of Minnesota associate professor of chemical engineering Renata Wentzcovitch and her team of researchers have confirmed the properties of a mineral (post-perovskite) that may form near the Earth's core in a layer called the D'' region.

The work offers new insight for interpreting properties of this region. The D'' (Dee double prime) layer surrounds Earth's core and is between 0 and 186 miles thick. It is at the interface between two chemically distinct regions, the rocky mantle and the metallic core. The article, "MgSiO3 post-perovskite at D'' conditions," was published on Jan. 17 in Proceedings of the National Academy of Science.

The research "tells us how to better model Earth's internal processes," said Wentzcovitch. "Proper geodynamical modeling of the Earth is necessary to get a better grasp of the dynamics of the surface. You can't fully understand Earth's surface motion without understanding how it moves inside. What's unbelievable is how well we can model Earth on a big scale. At this scale, small details don't matter."

In 2004, Japanese researchers at the Tokyo Institute of Technology found that high temperatures and pressures transform perovskite, the major mineral in Earth's mantle, into a new mineral called post-perovskite. Wentzcovitch's group contributed to this discovery by determining the structure of post-perovskite and by calculating the pressure and temperature conditions for its existence. They matched the conditions in the D'' layer.

In the current work, Wentzcovitch and colleagues demonstrate that the seismic properties of post-perovskite are much like the previously inexplicable properties found in the D'' layer. This is the most convincing evidence that post-perovskite is in the D'' layer and produces its strange seismic properties.

"As the Earth cools, D'' becomes thicker. Its thickness is related to Earth's age and its aging processes. The discovery of post-perovskite in the D'' layer will also help us understand how the Earth has evolved," Wenttzcovitch said.

On the web: www.pnas.org/content/vol103/issue3/#GEOPHYSICS

Source: University of Minnesota

Related Stories

Recommended for you

Facts, beliefs, and identity: The seeds of science skepticism

January 22, 2017

Psychological researchers are working to understand the cognitive processes, ideologies, cultural demands, and conspiracy beliefs that cause smart people to resist scientific messages. Using surveys, experiments, observational ...

'Droneboarding' takes off in Latvia

January 22, 2017

Skirted on all sides by snow-clad pine forests, Latvia's remote Lake Ninieris would be the perfect picture of winter tranquility—were it not for the huge drone buzzing like a swarm of angry bees as it zooms above the solid ...

Singapore 2G switchoff highlights digital divide

January 22, 2017

When Singapore pulls the plug on its 2G mobile phone network this year, thousands of people could be stuck without a signal—digital have-nots left behind by the relentless march of technology.

0 comments

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.