Six ‘Must-Have’ Minerals for Life’s Emergence: Olivine, Pyrrhotite, Bridgmanite, Serpentine, Fougerite and Mackinawite

Autor: Adrian Ponce, Michael J. Russell
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Life
Volume 10
Issue 11
Life, Vol 10, Iss 291, p 291 (2020)
ISSN: 2075-1729
DOI: 10.3390/life10110291
Popis: Life cannot emerge on a planet or moon without the appropriate electrochemical disequilibria and the minerals that mediate energy-dissipative processes. Here, it is argued that four minerals, olivine ([Mg>
Fe]2SiO4), bridgmanite ([Mg,Fe]SiO3), serpentine ([Mg,Fe,]2-3Si2O5[OH)]4), and pyrrhotite (Fe(1&minus
x)S), are an essential requirement in planetary bodies to produce such disequilibria and, thereby, life. Yet only two minerals, fougerite ([Fe2+6xFe3+6(x&minus
1)O12H2(7&minus
3x)]2+·
[(CO2&minus
)·
3H2O]2&minus
) and mackinawite (Fe[Ni]S), are vital&mdash
comprising precipitate membranes&mdash
as initial &ldquo
free energy&rdquo
conductors and converters of such disequilibria, i.e., as the initiators of a CO2-reducing metabolism. The fact that wet and rocky bodies in the solar system much smaller than Earth or Venus do not reach the internal pressure (&ge
23 GPa) requirements in their mantles sufficient for producing bridgmanite and, therefore, are too reduced to stabilize and emit CO2&mdash
the staple of life&mdash
may explain the apparent absence or negligible concentrations of that gas on these bodies, and thereby serves as a constraint in the search for extraterrestrial life. The astrobiological challenge then is to search for worlds that (i) are large enough to generate internal pressures such as to produce bridgmanite or (ii) boast electron acceptors, including imported CO2, from extraterrestrial sources in their hydrospheres.
Databáze: OpenAIRE
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