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Martian Mineral Linked to Microbial Life on Earth

The earliest living organisms on Earth were capable of making a mineral found on Mars, according to research published in Geology.

The clay mineral stevensite has been used since as a beauty treatment since ancient times, but scientists had believed that deposits could only be formed in harsh conditions like volcanic lava and hot alkali lakes.

Now a team led by Dr Bob Burne of The Australian National University has found that living microbes create an environment that allows stevensite to form, raising new questions about stevensite found on Mars.

“It’s much more likely that the stevensite on Mars is made geologically, from volcanic activity,” Burne said. “But our finding – that stevensite can form around biological organisms – will encourage re-interpretation of these Martian deposits and their possible links to life on that planet.”

Burne and colleagues found that microbes can become encrusted by stevensite. This protects their delicate insides and provides the rigidity to allow them to build reef-like structures called microbialites.

“Microbialites are the earliest large-scale evidence of life on Earth,” Burne said. “They demonstrate how microscopic organisms are able to join together to build enormous structures that sometimes rivalled the size of today's coral reefs.”

Burne said that the process still happens today in some isolated places like Shark Bay and Lake Clifton in Western Australia.

“Stevensite is usually assumed to require highly alkaline conditions to form, such as volcanic soda lakes. But our stevensite microbialites grow in a lake less salty than seawater and with near-neutral pH.”

The findings also have implications for how some of the world’s largest oil reservoirs were formed.