Nitrogen isotopes in peridotitic diamonds from Fuxian, China: the mantle signature

✍ Scribed by Pierre Cartigny; Stuart Boyd; Jeff. Harris; Marc Javoy

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 295 KB
• Volume: 9
• Category: Article
• ISSN: 0954-4879
• DOI: 10.1046/j.1365-3121.1997.d01-26.x

✦ Synopsis

Nitrogen isotopes in peridotitic diamonds from Fuxian, China, suggest that the upper mantle δ^15^N‐value has been globally homogeneous since at least the Proterozoic (−5 to −8‰/ATM), with similar values for subcontinental and MORB mantle.

 In addition, Fuxian diamonds retain the memory of a primary nitrogen lower in δ^15^N (down to −25‰). For the first time δ^15^N‐ values in diamonds match those of enstatite chondrites, supporting a formation of the Earth from such meteorites and the idea of a heterogeneous accretion of the Earth’s volatiles.

 Nitrogen concentrations in diamonds are believed to depend strongly on the rate of the diamond growth and not to be an indicator of C/N ratios of the fluids from which they grew.