[meteorite-list] Non-biological Organic Carbon Found to Originate on Mars

[Ron Baalke]

NEWS RELEASE FROM THE PLANETARY SCIENCE INSTITUTE

FROM:
Alan Fischer
Public Information Officer
Planetary Science Institute
520-382-0411
520-622-6300
fischer at psi.edu

Non-biological Organic Carbon Found to Originate on Mars

Tucson, Arizona, May 24, 2012 - Molecules containing carbon and hydrogen - 
the building blocks of all life on Earth - have been the targets of missions 
to Mars from Viking to the present day. While these molecules have previously 
been noticed in meteorites from Mars, scientists have disagreed about how 
this organic carbon was formed and whether or not it came from Mars. 

Theories about their origin include contamination from Earth or other meteorites, 
the results of chemical reactions on Mars, or that they are the remnants of 
ancient Martian biological life.   

A new paper published May 24 in Science Express by Carnegie's Andrew Steele and 
a consortium of scientists that includes Planetary Science Institute's Marc Fries 
provides strong evidence that this carbon did, indeed, originate on Mars, 
although it is not of biological origin. These findings give researchers insight 
into the chemical processes taking place on Mars and will help aid future quests 
for evidence of ancient or modern Martian life

Steele's team examined samples from 11 Martian meteorites whose ages span about 
4.2 billion years of Martian history. They detected large carbon compounds in 10 
of them. The molecules were found inside of grains of crystallized minerals. 
Since these molecules were found in Martian meteorites of such an extraordinary 
span of ages, their presence means that Mars has been making its own organic 
compounds throughout its history and apparently continues to do so today.  

"We knew these organic compounds were in the Martian meteorites, but until we 
performed this study no one knew exactly where they were in the rocks or how 
they were formed," said Fries, a research scientist at the Planetary Science 
Institute. "It was a puzzle, and now we finally have enough pieces in place to 
say, okay, now we understand what is going on here."

Using an array of sophisticated research techniques, the team was able to show 
that at least some of the macromolecules of carbon were indigenous to the 
meteorites themselves and not contamination from Earth.

"What this all means is that Mars is making its own organic compounds. Previous 
to this, we thought that carbon compounds on Mars only fell there in meteorites, 
or perhaps were bound up in any life forms that might be living there. Now we 
know that simply finding organic compounds that aren't from meteorites doesn't 
automatically mean that they come from life," Fries said. "While it sounds 
like it complicates things, it actually gives us a clearer picture of Mars and 
will help us build robust conclusions about whether anything is, or has been, 
alive there."

In a separate paper going to press in American Mineralogist, Steele and his 
team studied a meteorite called Allan Hills 84001 that was reported to contain 
relicts of ancient biological life on Mars. The paper demonstrated that these 
supposed remnants could have been created by chemical reactions involving the 
graphite form of carbon, rather than biological processes. Both of these papers 
reveal a pool of reduced carbon on Mars and will help scientist involved in 
future Mars missions distinguish these non-biologically formed molecules from 
potential life. 

The research for the Science Express paper was funded by NASA Astrobiology, Mars 
and Cosmochemistry programs, the W.M. Keck Foundation, the Natural Science and 
Engineering Research Council of Canada, and the Carnegie Institution for Science. 
The research for the American Mineralogist paper was supported by NASA 
Astrobiology, Mars and Cosmochemistry programs.


CONTACT:
Marc Fries
Research Scientist
fries at psi.edu
619-789-7981
  
PSI INFORMATION:
Mark V. Sykes
Director
520-622-6300
sykes at psi.edu