[meteorite-list] Meteor Impacts: Life's Jump Starter?

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Mon Aug 8 13:57:39 2005
Message-ID: <42F79CF0.7B2B2612_at_bhil.com>

Hi, All

    Comets were all the rage in the late
XVIIth century, Haley and all that. When
the great Isaac Newton, smartest and craziest
of them all, realize that comets were indeed
celestial bodies in orbits, it took him about
2 seconds to realize that the Earth must have
had head-on collisions with comets countless
times.
    This disturbed old Isaac because he
believed in a beneficent God, and that
seemed a rather nasty things for Him to
do to His Worlds. So, he quickly evolved
the theory that comets were the "bringers
of life" to the planets, supplying them
with water, volatiles, precious goods and
supplies life needed, and refreshing them
from time to time.
    He didn't think of them as bringing life,
which he regarded as created, but it is a
surprisingly quick and deft theoretical leap,
to the modern notion that early comets may
have supplied volatiles, especially water, to
the early Earth. It's a notion we still argue
about, deuterium ratios and such.
    Isaac got there in about 5 minutes of
thinking time. Of course, he spent 98% of his
intellectual time and energy on reconciling
the chronology of the Bible, and only in his
off-hand moments did he bother to work out
the theory of universal gravitation, the inverse
square law, and all the rest of it, and then
only because he was asked repeatedly to do so.
He did it so they would all shut up and he could
get back to the really important stuff...


Sterling K. Webb
-----------------------------------------
Ron Baalke wrote:

> http://www.geosociety.org/news/pr/05-25.htm
>
> Geological Society of America News Release
>
> 8 August 2005
> GSA Release No. 05-25
>
> Contact: Ann Cairns, acairns_at_geosociety.org
> Director - Communications and Marketing
> (303) 357-1056, fax 303-357-1074
>
> Meteor Impacts: Life's Jump Starter?
>
> Meteor impacts are generally regarded as monstrous killers and one of
> the causes of mass extinctions throughout the history of life. But there
> is a chance the heavy bombardment of Earth by meteors during the
> planet's youth actually spurred early life on our planet, say Canadian
> geologists.
>
> A study of the Haughton Impact Crater on Devon Island, in the Canadian
> Arctic, has revealed some very life-friendly features at ground zero.
> These include hydrothermal systems, blasted rocks that are easier for
> microbes to inhabit, plus the cozy, protected basin created by the
> crater itself. If true, impact craters could represent some of the best
> sites to look for signs of past or present life on Mars and other planets.
>
> A presentation on the biological effects of impacts is scheduled for
> Monday, 8 August, at Earth System Processes 2, a meeting co-convened by
> the Geological Society of America and Geological Association of Canada
> this week in Calgary, Alberta, Canada.
>
> The idea that meteor impacts could benefit or even create conditions
> suitable for the beginning of early life struck Canadian Space Agency
> geologist Gordon Osinski while he and colleagues were conducting a
> geological survey of the 24-kilometer (15-mile) diameter Haughton
> Crater. Along the rim of the crater they noticed what looked like
> fossilized hydrothermal pipes, a few meters in diameter.
>
> "That set the bells ringing about possible biological implications,"
> said Osinski. Hydrothermal systems are thought by many people to be the
> favourable places for life to evolve."
>
> Detailed mineralogical analyses have since revealed that when the
> Haughton meteor smacked into the icy ground 23 million years ago it
> created not only a crater, but fractured the ground in such a way as to
> create a system of steamy hydrothermal springs reaching temperatures of
> 250 degrees C. The heat appears to have gradually dropped over a period
> of tens of thousands of years, the researchers report.
>
> Besides providing heat and cracking the ground, the impact also created
> pore spaces in otherwise dense granitic rocks, giving microbes more
> access to the minerals and the surfaces inside the rocks - basically
> more real estate and more supplies.
>
> The shocked rocks are also more translucent, which would be beneficial
> to organisms that possessing with any photosynthetic capabilities.
>
> A crater shape itself also might serve as a protective environment, says
> Osinski. As such, impact craters are also good places to store evidence
> of past life. On Earth many craters fill with water and become lakes.
> Lakes accumulate sediments, the layers of which are a geological archive
> of the time after the crater formed. The Haughton Impact crater, for
> instance, contains the only Miocene-age sediments in the entire Canadian
> Arctic.
>
> "One of the most interesting aspects of the Haughton Impact Crater is
> that it's in a polar desert," said Osinski. The dry, frigid weather
> makes for a barren landscape that's easy to study, he said. The same
> features make it one of the more Mars-like places on Earth.
>
> "Most people put impacts with mass extinctions," said Osinski. "What
> we're trying to say is that following the impact, the impact sites are
> actually more favorable to life than the surrounding terrain."
>
> It's interesting to note, says Osinski, that on Earth the heaviest
> meteor bombardment of the planet happened at about the same time as life
> is believed to have started: around 3.8 billion years ago. Impact
> craters of that age were long ago erased on Earth by erosion, volcanic
> resurfacing and plate tectonics.
>
> But other planets and moons - including Mars - still bear the cosmic
> scars of that early debris-clogged period in the solar system. It may be
> possible, therefore, that the best places to look for at least fossil
> evidence of life on Mars is inside those very same craters, he said.
>
> "What we're doing is trying to narrow down the search area," said Osinski.
>
> Impact Craters as Habitats for Life on Early Earth and Mars
> Monday, 8 August, 9:20 am MDT
> Eau Claire North/South, Calgary Westin Hotel
> Abstract may be viewed at
> http://gsa.confex.com/gsa/2005ESP/finalprogram/abstract_88952.htm
>
Received on Mon 08 Aug 2005 01:57:04 PM PDT