Diamonds and Rust at the Earth’s Core-Mantle Boundary

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Scientists in ASU’s School of Earth and Space Exploration assist in discovery of potential 'diamond factory' that may have existed at the core-mantle boundary for billions of years.

Scientists in ASU’s School of Earth and Space Exploration assist in discovery of potential 'diamond factory' that may have existed at the core-mantle boundary for billions of years.

Steel rusts by water and air on the Earth’s surface. But what about deep inside the Earth’s interior?

The Earth’s core is the largest carbon storage on Earth – roughly 90% is buried there. Scientists have shown that the oceanic crust that sits on top of tectonic plates and falls into the interior (in a process called subduction) contains hydrous minerals, and can sometimes descend all the way to the core-mantle boundary.

The temperature at the core-mantle boundary is at least twice as hot as lava, and high enough that water can be released from the hydrous minerals. Therefore, a chemical reaction similar to rusting steel could occur at Earth’s core-mantle boundary.

Read more at Arizona State University

Image: The iron-carbon alloy reacted with water at high pressure and high temperature conditions related to the Earth’s deep mantle in a diamond-anvil cell. (Credit: Arizona State University)