Nitrogen Incorporation in Potassic and Micro- and Meso-Porous Minerals: Potential Biogeochemical Records and Targets for Mars Sampling

Matthew P. Nikitczuk, Gray Edward Bebout, Charles A. Geiger, Tsutomu Ota, Takuya Kunihiro, John F. Mustard, Sæmundur A. Halldórsson, Eizou Nakamura

Research output: Contribution to journalArticlepeer-review

Abstract

We measured the N concentrations and isotopic compositions of 44 samples of terrestrial potassic and micro- and meso-porous minerals and a small number of whole-rocks to determine the extent to which N is incorporated and stored during weathering and low-temperature hydrothermal alteration in Mars surface/near-surface environments. The selection of these minerals and other materials was partly guided by the study of altered volcanic glass from Antarctica and Iceland, in which the incorporation of N as NH4+ in phyllosilicates is indicated by correlated concentrations of N and the LILEs (i.e., K, Ba, Rb, Cs), with scatter likely related to the presence of exchanged, occluded/trapped, or encapsulated organic/inorganic N occurring within structural cavities (e.g., in zeolites). The phyllosilicates, zeolites, and sulfates analyzed in this study contain between 0 and 99,120 ppm N and have δ15Nair values of -34‰ to +65‰. Most of these minerals, and the few siliceous hydrothermal deposits that were analyzed, have δ15N consistent with the incorporation of biologically processed N during low-temperature hydrothermal or weathering processes. Secondary ion mass spectrometry on altered hyaloclastites demonstrates the residency of N in smectites and zeolites, and silica. We suggest that geological materials known on Earth to incorporate and store N and known to be abundant at, or near, the surface of Mars should be considered targets for upcoming Mars sample return with the intent to identify any signs of ancient or modern life.

Original languageEnglish
Pages (from-to)1293-1309
Number of pages17
JournalAstrobiology
Volume22
Issue number11
DOIs
Publication statusPublished - Nov 1 2022

Keywords

  • Biogeochemistry
  • Mars
  • Planetary habitability and biosignatures
  • Silicates. Astrobiology 22, 1293–1309
  • Stable isotopes

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Space and Planetary Science

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