Skip to content

Research at St Andrews

The formation of sulfate, nitrate and perchlorate salts in the martian atmosphere

Research output: Contribution to journalArticle

Author(s)

Megan L. Smith, M.W. Claire, D.C. Catling, K.J. Zahnle

School/Research organisations

Abstract

In extremely arid regions on Earth, such as the Atacama Desert, nitrate, sulfate and perchlorate salts form in the atmosphere and accumulate on the surface from dry deposition according to diagnostic evidence in their oxygen isotopes. Salts of similar oxyanions should have formed in the atmosphere of Mars because of comparable photochemical reactions. We use a 1-D photochemical model to calculate the deposition rates of sulfate, nitrogen oxyanions, and perchlorate from Mars' atmosphere, given a plausible range of volcanic fluxes of sulfur- and chlorine-containing gases in the past. To calculate integrated fluxes over time, we assume that throughout the last 3. byr (the Amazonian eon), the typical background atmosphere would have been similar to today's cold and dry environment. If the soil has been mixed by impact perturbations to a characteristic depth of ~2. m during this time, given a time-average volcanic flux 0.1% of the modern terrestrial volcanic flux, the model suggests that the soil would have accumulated 1.0-1.7. wt.% SO42- and 0.2-0.4. wt.% N in the form of pernitrate (peroxynitrate) or nitrate. The calculated sulfate concentration is consistent with in situ observations of soils from rovers and landers and orbital gamma ray spectroscopy. However, nitrates or pernitrates are yet to be detected. The modeled formation of perchlorate via purely gas-phase oxidation of volcanically-derived chlorine is insufficient by orders of magnitude to explain 0.4-0.6. wt.% ClO4- measured by NASA's Phoenix Lander. The far smaller amount of ozone in the martian atmosphere compared to the terrestrial atmosphere and the colder, drier conditions are the cause of lower rates of gas phase oxidation of chlorine volatiles to perchloric acid. Our calculations imply that non-gas-phase processes not included in the photochemical model, such as heterogeneous reactions, are likely important for the formation of perchlorate and are yet to be identified.
Close

Details

Original languageEnglish
Pages (from-to)51-64
Number of pages14
JournalIcarus
Volume231
Early online date7 Dec 2013
DOIs
Publication statusPublished - 1 Mar 2014

    Research areas

  • Mars, Mars, atmosphere, Photochemistry, Atmosphere, chemistry, Mars, surface

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Indigenous organic-oxidized fluid interactions in the Tissint Mars meteorite

    Jaramillo, E. A., Royle, S. H., Claire, M. W., Kounaves, S. P. & Sephton, M. A., 18 Mar 2019, In : Geophysical Research Letters. Early View

    Research output: Contribution to journalArticle

  2. Triple oxygen isotope analysis of nitrate using isotope exchange - cavity ringdown laser spectroscopy

    Gázquez, F. & Claire, M. W., 30 Nov 2018, In : Rapid Communications in Mass Spectrometry. 32, 22, p. 1949-1961

    Research output: Contribution to journalArticle

  3. Long-term planetary habitability and the carbonate-silicate cycle

    Rushby, A. J., Johnson, M., Mills, B. J. W., Watson, A. J. & Claire, M. W., 1 May 2018, In : Astrobiology. 18, 5, p. 469-480 12 p.

    Research output: Contribution to journalArticle

  4. Two-billion-year-old evaporites capture Earth's great oxidation

    Blättler, C., Claire, M., Prave, A. R., Zerkle, A. L. & Warke, M. R., 22 Mar 2018, In : Science. eaar2687.

    Research output: Contribution to journalArticle

  5. Evaluation of the Tindouf Basin region in Southern Morocco as an analog site for soil geochemistry on Noachian Mars

    Oberlin, E. A., Claire, M. W. & Kounaves, S., 9 Feb 2018, In : Astrobiology. 18, 8

    Research output: Contribution to journalArticle

Related by journal

  1. Effects of UV-organic interaction and Martian conditions on the survivability of organics

    Laurent, B., Cousins, C. R., Pereira, M. F. C. & Martins, Z., 24 Jan 2019, In : Icarus. In press

    Research output: Contribution to journalArticle

  2. UV luminescence characterisation of organics in Mars-analogue substrates

    Laurent, B., Cousins, C. R., Gunn, M., Huntly, C., Cross, R. & Allender, E., 15 Mar 2019, In : Icarus. 321, p. 929-937

    Research output: Contribution to journalArticle

  3. Global analysis of gully composition using manual and automated exploration of CRISM imagery

    Allender, E. & Stepinksi, T. F., 1 Mar 2018, In : Icarus. 302, p. 319-329 10 p.

    Research output: Contribution to journalArticle

  4. Anoxic atmospheres on Mars driven by volcanism: implications for past environments and life

    Sholes, S. F., Smith, M. L., Claire, M. W., Zahnle, K. J. & Catling, D. C., 1 Jul 2017, In : Icarus. 290, p. 46-62 17 p.

    Research output: Contribution to journalArticle

  5. Automatic, exploratory mineralogical mapping of CRISM imagery using summary product signatures

    Allender, E. & Stepinski, T. F., 1 Jan 2017, In : Icarus. 281, p. 151-161 10 p.

    Research output: Contribution to journalArticle

ID: 118183237