Fig. 2: Nitrogen K-edge XANES spectra.
From: In-situ preservation of nitrogen-bearing organics in Noachian Martian carbonates
a A whole spectral image. The upper three (Crb-1 to Crb-3) are ALH carbonates, the others are the selected reference compounds. b An enlarged area of the energy between 397 and 403.5 eV. Significant absorption peaks for N2 (400.8 eV; magenta), NaNO3 (401.4 and 405.2 eV; green), and the organic compounds (398–402.5 eV; light blue) are highlighted in both images. Major N-bearing groups of imino, nitrile, N-heterocyclic, and amino groups in this energy range are plotted. The other XANES spectra obtained in this study are shown in Supplementary Figs 1–3.
