Nitrogen isotopic composition of the MORB mantle: a reevaluation

Mohapatra, Ratan K. ; Murty, S. V. S. (2004) Nitrogen isotopic composition of the MORB mantle: a reevaluation Geochemistry, Geophysics, Geosystems, 5 (1). ISSN 1525-2027

Full text not available from this repository.

Official URL: http://www.agu.org/pubs/crossref/2004/2003GC000612...

Related URL: http://dx.doi.org/10.1029/2003GC000612

Abstract

Nitrogen in the mantle source of mid oceanic ridge basalts (MORBs) is commonly believed to have δ15N~−5‰. This is based on a (selective) statistical average drawn from nitrogen isotopic data obtained simultaneously with argon from MORBs. However, on critical evaluation, using the accompanying 40Ar/36Ar data, we show this approach to be somewhat ambiguous. Considering the fact that MORBs can have a number of geochemical components in them, as has been shown by several recent studies, the approach of statistical averaging may actually point to a mixture rather than the true mantle end-member. A more reasonable approach, also used for deriving the mantle noble gas signatures, suggests nitrogen in the MORB mantle to be much lighter (~−15‰) in its isotopic composition. Such a signature is consistent with nitrogen data from MORBs as well as from other mantle derived samples that are believed to have sampled volatiles from the MORB mantle.

Item Type:Article
Source:Copyright of this article belongs to American Geophysical Union.
ID Code:70234
Deposited On:21 Nov 2011 09:41
Last Modified:21 Nov 2011 09:41

Repository Staff Only: item control page