[meteorite-list] Martian Mineral Could Be Linked to Microbes (Stevensite)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 21 May 2014 11:29:35 -0700 (PDT)
Message-ID: <201405211829.s4LITZ7g018016_at_zagami.jpl.nasa.gov>


Martian mineral could be linked to microbes
Australian National University
May 20, 2014
Scientists have discovered that the earliest living organisms on Earth
were capable of making a mineral that may be found on Mars.

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

Researchers led by Dr Bob Burne from the ANU Research School of Earth
Sciences have found living microbes create an environment that allows
stevensite to form, raising new questions about the stevensite found on

"It's much more likely that the stevensite on Mars is made geologically,
from volcanic activity," Dr 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."

Dr Burne and his colleagues from ANU, University of Western Australia
and rock imaging company Lithicon, have found microbes can become encrusted
by stevensite, which 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,"
Dr 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."

He said 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."

One of the paper's authors, Dr Penny King from ANU, is a science co-investigator
on NASA's Mars Curiosity rover, which uncovered the presence of possible
Martian stevensite.

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

The discovery was made using ANU-developed imaging technology licensed
to Lithicon. The data was run on Raijin, the most powerful supercomputer
in the Southern Hemisphere, based at the National Computational Infrastructure
in Canberra.

The research is published in Geology.
Received on Wed 21 May 2014 02:29:35 PM PDT

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