Unusual stones resembling cauliflower, which were discovered in 2008 on the surface of the Red Planet using the Spirit rover near an outcrop called Home Plate, located in Gusev Crater, attracted the attention of scientists. They look like cauliflower or corals, but were these strange rocks formed by microbes, wind, or other processes determined their formation.
Analyzes of these stones using the mini-TES (Mini-Thermal Emission Spectrometer) instrument of the Spirit rover confirmed that the stones are composed of nearly pure silica (SiO2), a mineral that forms in hot, volcanic conditions. Rainwater and snow penetrate cracks in the ground and come into contact with hot rocks, resulting in a mixture of water and steam that rises to the surface, dissolving silicon dioxide and other minerals along the way, which then precipitate near the point where the water comes to the surface, called hydrothermal source. On Earth, silica precipitating from the water can be observed around the hot springs of Yellowstone Park.
Both in Yellowstone and in the area near the Taupo volcano in New Zealand, as well as in Iceland, bacteria that love heat are closely involved in the formation of unusual formations from silica, bizarre shapes, reminiscent of Martian stones in the form of "cauliflower". In the new study, planetary scientist Stephen Ruff and geology professor Jack Farmer, both from Arizona State University, USA, are investigating the possibility that microbes could also be involved in the formation of Martian rocks.
In their work, the researchers analyze samples of silica from the El Tatio Valley of the Geysers in the Chilean Atacama Desert, a place on our planet that well mimics Martian conditions, in an attempt to detect traces of bacteria in these minerals. If such an impact is found, it would give scientists reason to believe that the Martian silicas found in the Gusev crater were also formed by the action of microorganisms.
The results of the study were presented at the 46th conference on the sciences of the moon and planets.