Discovery of Diamonds Formed in the Earth’s Crust

Research Press Release | June 12, 2015

Carbonaceous material found in serpentinite (Fig. 1) from Sicily’s Hyblean Plateau was analyzed primarily by a group at Hokkaido University using a transmission electron microscope and micro Raman scattering spectrometer.
Carbonaceous material found in serpentinite (Fig. 1) from Sicily’s Hyblean Plateau was analyzed primarily by a group at Hokkaido University using a transmission electron microscope and micro Raman scattering spectrometer.



Press Release
Key Points * Nanodiamonds have been discovered in carbonaceous material in serpentinite.

* Nanodiamonds are formed in the earth’s crust at low temperatures and pressures of less than 300 ºC and 1,000 atmospheric pressure (or atm).

* It is expected that nanodiamonds will also be discovered in sedimentary rock and crude oil.

Overview Diamonds found previously have all been formed deep in the earth at high temperatures and pressures. On the other hand, while it was understood that diamonds can be formed experimentally at the low temperatures and pressures associated with the earth’s crust, none had been found in crustal rock.


A joint research team from the Russian Academy of Sciences, Hokkaido University, and the University of Catania has used a variety of methods to analyze carbonaceous material in serpentinite produced by reacting peridotite with water and carbon dioxide at the low temperatures and pressures associated with the earth’s crust. Results show nanodiamonds of a few nm in size.


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Furthermore, it is now understood that nanodiamonds are formed in the earth’s crust at temperatures and pressures of less than 300 ºC and 1,000 atmospheric pressure (or atm), and at depths of less than 5 km. This is the first discovery of diamonds produced naturally on the earth at low temperatures and pressures outside the stability region.

Inquiries

Akira KOUCHI, Professor, Astrophysical Chemistry/ Ice & Planetary Science Group, Institute of Low Temperature Science, Hokkaido University

TEL: +81-11-706-5500

FAX: +81-11-706-7042

E-mail: kouchi@lowtem.hokudai.ac.jp

Japanese

Link

地殻内で形成されたダイヤモンドを発見 
Publications Nanodiamond Finding in the Hyblean Shallow Mantle XenolithsScientific Reports (Nature Publishing Group)(2015.6.1)

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