Nitrogen isotopologues reveal the origin of nitrogen in our planetary interior - Jabrane Labidi
We've published our work in the journal Nature. We show that we can eliminate the confounding effect of air contamination in volcanic and hydrothermal gases, for the specific case of nitrogen. By substracting air contamination, we derive the di-nitrogen (N2) molecular weight in various mantle sources.
A new finding here is that various mantle sources, with variable 15N/14N ratios, have a near-constant N2/3He ratio. Because 3He is in the deep Earth is not recycled, the constant N2/3He ratios argue against nitrogen addition via subduction in various mantle sources.
We built a 2-box model to show how over 4.5 Ga, the mantle and air may have exchanged considerably less nitrogen than previously suggested. In other words, the possibility that mantle nitrogen is primordial can no longer be excluced. In this theory, nitrogen would have been inherited from the time the Earth was being built via planetary accretion.
proud of this work!
Here is a link to view the pdf of the article, for free :