Compilation of nitrogen isotope ratios and abundances in iron meteorites determined by step-heating or secondary ion mass spectrometry (SIMS)

The table compiles published nitrogen isotope ratios (15N/14N, expressed as δ15N, where δ15N is the per mil (‰) deviation from the atmospheric 15N/14N ratio of 0.003676; Nier, 1950) and nitrogen abundances in iron meteorites, determined by step-heating or secondary ion mass spectrometry (SIMS). It includes details on the analytical method used and the temperature steps considered. The classification of the iron meteorites is based on the Meteoritical Bulletin Database, July 2025. The non-carbonaceous (NC) vs. carbonaceous (CC) heritage of several ungrouped iron meteorites is from Spitzer et al. (2025).

Data sources:

Franchi I. A., Wright I. P. and Pillinger C. T. (1993) Constraints on the formation conditions of iron meteorites based on concentrations and isotopic compositions of nitrogen. Geochim. Cosmochim. Acta 57, 3105–3121. https://doi.org/10.1016/0016-7037(93)90297-A
Mathew K. J., Palma R. L., Marti K. and Lavielle B. (2000) Isotopic signatures and origin of nitrogen in IIE and IVA iron meteorites. Geochim. Cosmochim. Acta 64, 545–557. https://doi.org/10.1016/S0016-7037(99)00316-6
Murty S. V. S. and Marti K. (1994) Nitrogen isotopic signatures in Cape York: Implications for formation of Group III A irons. Geochim. Cosmochim. Acta 58, 1841–1848. https://doi.org/10.1016/0016-7037(94)90540-1
Murty S. V. S., Ghosh S. and Ray D. (2019) Noble gases and nitrogen in Raghunathpura (IIAB) and Nyaung (IIIAB) iron meteorites. Meteorit. Planet. Sci. 54, 90–103. https://doi.org/10.1111/maps.13195
Pepin R. O. and Becker R. H. (1982) Nitrogen isotopes in iron meteorites. Meteoritics 17, 269.
Ponganis K. V. and Marti K. (2007) Nitrogen components in IAB/IIICD iron meteorites. Meteorit. Planet. Sci 42, 331–346. https://doi.org/10.1111/j.1945-5100.2007.tb00237.x
Prombo C. A. and Clayton R. N. (1993) Nitrogen isotopic compositions of iron meteorites. Geochim. Cosmochim. Acta 57, 3749–3761. https://doi.org/10.1016/0016-7037(93)90153-N
Sugiura N. (1998) Ion probe measurements of carbon and nitrogen in iron meteorites. Meteorit. Planet. Sci 33, 393–409. https://doi.org/10.1111/j.1945-5100.1998.tb01645.x
Sugiura N., Ikeda Y., Zashu S. and Wasson J. T. (2000) Nitrogen-isotopic compositions of IIIE iron meteorites. Meteorit. Planet. Sci 35, 749–756. https://doi.org/10.1111/j.1945-5100.2000.tb01459.x

Additional references:

Nier A. (1950) A redetermination of the relative abundances of the isotopes of carbon, nitrogen, oxygen, argon, and potassium. Physical Review 77, 789–793.
https://doi.org/10.1103/PhysRev.77.789
Spitzer F., Burkhardt C., Kruijer T. S. and Kleine T. (2025) Comparison of the earliest NC and CC planetesimals: Evidence from ungrouped iron meteorites. Geochim. Cosmochim. Acta 397, 134–148. https://doi.org/10.1016/j.gca.2025.03.021