Relic of life in that Martian meteorite? A fresh look (Forwarded)

Carnegie Institution of Washington
Washington, D.C.

Carnegie contacts:

Andrew Steele, 202-793-1247
Marilyn Fogel, 202-478- 8981
Marc Fries, 202-478-8993

March 22, 2006

Relic of life in that Martian meteorite? A fresh look

Washington, D.C. -- Since the mid-1990s a great debate has raged over
whether organic compounds and tiny globules of carbonate minerals imbedded
in the Martian meteorite Allan Hills 84001 were processed by living
creatures from the Red Planet. The materials have been under intense
scrutiny ever since. Scientists at the Carnegie Institution's Geophysical
Laboratory, with colleagues, [1] have taken a fresh look at how material
associated with carbonate globules was created using sophisticated
instrumentation and they compared the results to analogous globules from a
volcanic complex on Svalbard, an island north of Norway. It does not
appear that living organisms were at work. The research is presented at
NASA's Astrobiology Science Conference (AbSciCon) 2006 at the Ronald
Reagan Building in Washington, D.C. March 26-30. See
http://abscicon2006.arc.nasa.gov/ for details.

To some, the tiny carbonate globules from the meteorite seem to resemble
minerals that arise from microbial activity on Earth. The team focused on
whether macromolecular carbon (MMC) in and around the globules was
processed organically or not -- an unresolved issue. The team had a
complete depth profile of the meteorite. Lead author Andrew Steele
explained, "By using micro-Raman spectroscopy and a scanning electron
microscope we could detect both the structure of the minerals and the
forms of carbon present. We did a similar analysis on carbonate globules
from Earth in terrain analogous to Mars -- the Bockjord Volcanic Complex
on Svalbard -- for comparison."

The researchers found that the macromolecular carbon is always associated
with the mineral magnetite. This association is important because
magnetite is known to act as a catalyst in the formation of MMC.
Macromolecular carbon present within the carbonate globules in ALH84001
may represent the first evidence of non-biological synthesis of organic
molecules on Mars.

"Although we haven't settled the debate on whether evidence of life is
contained in Allan Hills, we have shown that these carbon complexes likely
formed by non-biological processing on Mars," concluded Steele.

Talk and poster schedule subject to change. See
http://abscicon2006.arc.nasa.gov/agenda.php for the latest information.

[1] Andrew Steele, et al., "A comprehensive imaging and Raman spectroscopy
study of ALH84001 and a terrestrial analogue from Svalbard"
Monday, March 27th, 10:15 am
Ronald Reagan Building, Horizon A & B, Session 3: Cold Mars Analogue
Environments
[*] The research was part of the Arctic Mars Analog Svalbard Expedition
(AMASE). Researchers come from the following institutions: lead
institution, Physics of Geological Processes, University of Oslo; The
Carnegie Institution of Washington, Geophysical Laboratory and Department
of Terrestrial Magnetism; NASA Jet Propulsion Laboratory; University of
Leeds; University of Oxford; Universidad de Burgos, Spain; The Smithsonian
Institution; Penn State University; Geological Institute, University of
Oslo and Idaho National Laboratory.

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This work is supported by the NASA Astrobiology Institute (NAI). The NAI,
founded in 1998, is a partnership between NASA, 16 major U.S. teams and
six international consortia. NAI's goal is to promote, conduct, and lead
integrated multidisciplinary astrobiology research and to train a new
generation of astrobiology researchers. For more information about the NAI
on the Internet, visit:
http://nai.nasa.gov/