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Nitrogen isotopes in peridotitic diamonds from Fuxian, China: the mantle signature
Author(s) -
Cartigny Pierre,
Boyd Stuart,
Harris Jeff.,
Javoy Marc
Publication year - 1997
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1046/j.1365-3121.1997.d01-26.x
Subject(s) - enstatite , geology , chondrite , mantle (geology) , geochemistry , isotopes of nitrogen , proterozoic , meteorite , craton , diamond , nitrogen , homogeneous , isotope , isotopic signature , earth science , astrobiology , paleontology , tectonics , chemistry , organic chemistry , physics , quantum mechanics , thermodynamics
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.