Shedding New Light on Earth’s Deepest Mechanisms Using Diamonds

Diamonds from Kankan, Guinea, analyzed in this study The imperfections inside the diamond are small inclusions of a mineral called ferropericlase, which is from the lower mantle.
Credit: Anetta Banas

Uncovering New Understanding of Earth’s Carbon Cycle

University of Alberta PhD student authors paper shedding new light on Earth’s deepest mechanisms using information from diamonds.

A new study led by a University of Alberta PhD student—and published in Nature—is examining the Earth’s carbon cycle in new depth, using diamonds as breadcrumbs of insight into some of Earth’s deepest geologic mechanisms.

“Geologists have recently come to the realization that some of the largest, most valuable diamonds are from the deepest portions of our planet,” said Margo Regier, PhD student in the Department of Earth and Atmospheric Sciences under the supervision of Graham Pearson and Thomas Stachel. “While we are not yet certain why diamonds can grow to larger sizes at these depths, we propose a model where these ‘superdeep’ diamonds crystallize from carbon-rich magmas, which may be critical for them to grow to their large sizes.”

Beyond their beauty and industrial applications, diamonds provide unique windows into the deep Earth, allowing scientists to examine the transport of carbon through the mantle.

“The vast majority of Earth’s carbon is actually stored in its silicate mantle, not in the atmosphere,” Regier explained. “If we are to fully understand Earth’s whole carbon cycle then we need to understand this vast reservoir of carbon deep underground.”

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