[meteorite-list] Origin Of Mysterious Subterranean Gases Identified, Says Researcher

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:23 2004
Message-ID: <200204041846.KAA13163_at_zagami.jpl.nasa.gov>

Department of Public Affairs
University of Toronto
Toronto, Ontario

CONTACT:

Professor Barbara Sherwood Lollar
Director, Stable Isotope Laboratory
Department of Geology
ph: (416) 978-0770; email: bsl_at_quartz.geology.utoronto.ca

U of T Public Affairs
ph: (416) 978-0260; email: lanna.crucefix_at_utoronto.ca

April 3, 2002

Origin of mysterious subterranean gases identified, says researcher

Gases similar to those that may have played a part in the formation of
the earliest life on the planet

By Lanna Crucefix

Evidence of gases similar to those that may have played a part in the
formation of the earliest life on the planet has been found by a U of
T geochemist.

Until now, it has been assumed that any evidence of the abiogenic, or
non-life-based, reactions that created the first simple hydrocarbons
on the early Earth had been erased by the organic reactions that have
dominated Earth since the evolution and proliferation of complex life.
However, Barbara Sherwood Lollar, a professor in the department of
geology and lead researcher of the study published in the April 4
issue of Nature, has found evidence of abiogenic gases in underground
mines. Life on Earth probably began from simple organic compounds,
including hydrocarbons that were formed from abiogenic reactions
involving water, carbon dioxide and methane.

Hydrocarbon gases have been found in deep rocks and groundwaters at
sites throughout the Canadian Shield and in Scandinavia and southern
Africa. "All of these areas are geologically similar, made of
Precambrian rocks which are billions of years old," she says. The
gases are usually trapped in fracture systems throughout the rock
and are released when mine drilling penetrates these rocks.

Gases from mines have been reported anecdotally from miners as far
back as the 1880s, says Sherwood Lollar, but their origin was a
mystery. "Gases are usually formed through microbial, or thermogenic
processes (which create oil and natural gas fields) but neither of
these processes was thought to occur in Precambrian rocks two
kilometres under the Earth's surface, which is the depth that our
samples came from."

Sherwood Lollar and her team examined certain gases from a mine near
Timmins, Ontario. Analyses of the gases' carbon and hydrogen isotope
ratios found that the gases matched hydrocarbons known to be the
result of abiotic reactions. "Until now, these types of gases had
only been known through laboratory experimentation, and from
extraterrestrial samples such as meteorites," Sherwood Lollar says.

The presence of these hydrocarbon gases deep in the earth raises
another exciting possibility, Sherwood Lollar says. "In recent years
it has been discovered that life on Earth extends far deeper than
ever thought possible. Deep microbial communities have been
discovered several kilometres under the Earth's surface and debate
has raged over what these microbes could be using as a food source."

According to Sherwood Lollar, the hydrocarbon and hydrogen gases
could be a food source. "These deep biosphere bacteria could 'digest'
the gases through a form of chemosynthesis -- similar to that known
to support life at the deep sea vents -- using the chemicals in the
gases in order to get energy for life."

Funding for this study was provided by the Natural Sciences and
Engineering Research Council of Canada and in part by Falconbridge Ltd.

[Lanna Crucefix is an assistant news services officer with the
Department of Public Affairs.]
Received on Thu 04 Apr 2002 01:46:42 PM PST