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Nanophase Goethite as a Promising Target in the Search for Past Life on Mars
Tara Djokic1,2, Patrick M Smith1,3,4, Jennifer O'Keefe5
1Australian Museum Research Institute, Sydney, New South Wales, Australia.
Astrobiology
|June 12, 2026
Summary
Microbial fossils, including bacteria and fungi, were found preserved in nanophase goethite. This discovery highlights nanophase goethite as a key target for searching for life on Mars.
Area of Science:
- Astrobiology
- Geology
- Paleontology
Background:
- Iron oxides and oxyhydroxides on Mars are key targets for detecting past microbial life.
- Limited research exists on microbial fossils within fluviolacustrine ferricrete, specifically nanophase goethite deposits.
- Understanding biosignatures in these Martian geological formations is crucial.
Purpose of the Study:
- To investigate microbial fossils in nanophase goethite.
- To assess the preservation potential of nanophase goethite for microfossils.
- To evaluate nanophase goethite deposits as targets for Mars exploration.
Main Methods:
- Scanning electron microscopy (SEM) was used to analyze microfossil morphotypes.
- Energy dispersive spectroscopy (EDS) was employed for elemental analysis.
- Microfossils were studied in laminated nanophase goethite from the McGraths Flat Lagerstätte.
Main Results:
- Exceptionally well-preserved microfossils, including bacteria and fungi, were identified.
- Diverse fossil morphotypes, both syngenetic and endolithic, were recognized.
- Nanophase goethite demonstrated excellent preservation of subcellular details.
Conclusions:
- Nanophase goethite is an exceptional medium for preserving microfossils across multiple microbial generations.
- The findings support nanophase goethite as a promising biosignature target for Mars exploration.
- This research expands our understanding of biosignatures in ferricrete deposits.
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