T58 New Voices in Geobiology II

Sunday, 22 September 2019
1:30 PM - 5:30 PM
Room 225AB, North Building

MICROBIAL IRON-SULFIDE MINERALS AS BIOSIGNATURES FOR THE SEARCH OF LIFE ON MARS

Paper number: T58-14
Program: Technical Sessions
Time: 4:45 PM – 5:00 PM

Authors

  • Aude Picard Presenting Author
    University of Nevada, Las Vegas, Las Vegas, NV

Abstract

On Earth, most iron sulfide mineral formation takes place in anoxic sedimentary environments, where sulfide is produced by sulfate-reducing microorganisms (SRM). SRM influence the physical properties and composition of iron-sulfide minerals (1, 2), suggesting that iron-sulfide minerals could be used as a proxy for the detection of microbial life in anoxic environments on other planets, such as Mars. The presence of iron-sulfide minerals in the subsurface of Mars has been suggested in previous studies, and our experimental studies could help decipher if Martian iron-sulfide minerals have a biological origin, have been influenced by prebiotic molecules, or are of abiotic origin. In this presentation, I will discuss the robustness of the biosignature suite associated with iron sulfide minerals, and will present new data on the evolution of iron-sulfide minerals submitted to oxidizing conditions, simulating exposure to the surface of Mars.

1. Picard A, Gartman A, Clarke DR, & Girguis PR (2018) Sulfate-reducing bacteria influence the nucleation and growth of mackinawite and greigite. Geochimica et Cosmochimica Acta 220:367-384. 2. Picard A, et al. (in review) Authigenic metastable iron sulfide minerals preserve microbial organic carbon preservation in anoxic environments. Chemical Geology.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-333245

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