Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Geology

Supervisor

Dr. Gordon Southam

Abstract

The detection of jarosite (K)Fe3(SO4)2OH6 on Mars has been interpreted as mineralogical evidence of acid-sulfate aqueous processes, including putative evidence of biological activity. Terrestrial habitats where acidic conditions occur are environments where microbiota thrive and generate biological signatures. A biotic and synthetic jarosite were produced to evaluate the ability and effectiveness of existing analytical methods to identify biosignatures in targeted geological materials. Using a comprehensive suite of microscopic (light microscopy, SEM and TEM), mineralogical (XRD), spectroscopic (IR, LIBS, Mössbauer, UV-Vis-NIR, and Raman) and mass spectrometry (ToF-SIMS) techniques, the two jarosites were found to be morphologically distinct. The identification of organic signatures in biogenic samples was masked by the iron-hydroxyl-sulfate matrix, but biogenicity was detectable using SEM and TEM which are not practical on Mars. Jarosite produced in 2-year-old abiotic control medium was similar to biogenic samples indicating that the presence of jarosite is not evidence of life.

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