[meteorite-list] Pebbly Rocks Testify to Old Streambed on Mars (MSL)
From: Steve Dunklee <steve.dunklee_at_meteoritecentral.com>
Date: Fri, 31 May 2013 01:57:00 -0700 (PDT)
I should add several billion years of carbon dioxide flow could cause a lot of erosion.
--- On Fri, 5/31/13, Steve Dunklee <steve.dunklee at yahoo.com> wrote:
> From: Steve Dunklee <steve.dunklee at yahoo.com>
> Subject: Re: [meteorite-list] Pebbly Rocks Testify to Old Streambed on Mars (MSL)
> To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>, "Ron Baalke" <baalke at zagami.jpl.nasa.gov>
> Date: Friday, May 31, 2013, 8:41 AM
> What is the composition of the
> pebbles? and other deposits? if there are not carbonates or
> other water soluable constiuentes then we may have to accept
> the flow of carbon dioxide as the cause of the water like
> erosion caused by the heating and cooling? on mars.
> where is the bog iron and limestone or other precipitates
> which would be formed by water? As much as I would wish for
> life and water on mars I see nothing to convince me yet.
> Steve Dunklee
> --- On Thu, 5/30/13, Ron Baalke <baalke at zagami.jpl.nasa.gov>
> > From: Ron Baalke <baalke at zagami.jpl.nasa.gov>
> > Subject: [meteorite-list] Pebbly Rocks Testify to Old
> Streambed on Mars (MSL)
> > To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>
> > Date: Thursday, May 30, 2013, 7:01 PM
> > http://www.jpl.nasa.gov/news/news.php?release=2013-181?
> > Pebbly Rocks Testify to Old Streambed on Mars
> > Jet Propulsion Laboratory
> > May 30, 2013
> > PASADENA, Calif. - Detailed analysis and review have
> > out
> > researchers' initial interpretation of
> > slabs that
> > NASA's Mars rover Curiosity investigated last year:
> They are
> > part of an
> > ancient streambed.
> > The rocks are the first ever found on Mars that
> > streambed
> > gravels. The sizes and shapes of the gravels embedded
> > these
> > conglomerate rocks -- from the size of sand particles
> to the
> > size of
> > golf balls -- enabled researchers to calculate the
> depth and
> > speed of
> > the water that once flowed at this location.
> > "We completed more rigorous quantification of the
> > to
> > characterize the size distribution and roundness of
> > pebbles and sand
> > that make up these conglomerates," said Rebecca
> Williams of
> > the
> > Planetary Science Institute, Tucson, Ariz., lead author
> of a
> > report
> > about them in the journal Science this week. "We ended
> > with a
> > calculation in the same range as our initial estimate
> > fall. At a
> > minimum, the stream was flowing at a speed equivalent
> to a
> > walking pace
> > -- a meter, or three feet, per second -- and it was
> > ankle-deep to
> > hip-deep."
> > Three pavement-like rocks examined with the telephoto
> > capability of
> > Curiosity's Mast Camera (Mastcam) during the rover's
> > 40 days on
> > Mars are the basis for the new report. One, "Goulburn,"
> > immediately
> > adjacent to the rover's "Bradbury Landing" touchdown
> > The other
> > two, "Link" and "Hottah," are about 165 and 330 feet
> (50 and
> > 100 meters)
> > to the southeast. Researchers also used the rover's
> > laser-shooting
> > Chemistry and Camera (ChemCam) instrument to
> investigate the
> > Link rock.
> > "These conglomerates look amazingly like streambed
> > on Earth,"
> > Williams said. "Most people are familiar with rounded
> > pebbles.
> > Maybe you've picked up a smoothed, round rock to skip
> > the water.
> > Seeing something so familiar on another world is
> > and also
> > gratifying."
> > The larger pebbles are not distributed evenly in the
> > conglomerate rocks.
> > In Hottah, researchers detected alternating
> > layers and sand
> > layers. This is common in streambed deposits on Earth
> > provides
> > additional evidence for stream flow on Mars. In
> > many of the
> > pebbles are touching each other, a sign that they
> > along the bed
> > of a stream.
> > "Our analysis of the amount of rounding of the pebbles
> > provided further
> > information," said Sanjeev Gupta of Imperial College,
> > London, a
> > co-author of the new report. "The rounding indicates
> > sustained flow. It
> > occurs as pebbles hit each other multiple times. This
> > a one-off
> > flow. It was sustained, certainly more than weeks or
> > though we
> > can't say exactly how long."
> > The stream carried the gravels at least a few miles,
> > kilometers, the
> > researchers estimated.
> > The atmosphere of modern Mars is too thin to make a
> > sustained stream
> > flow of water possible, though the planet holds large
> > quantities of
> > water ice. Several types of evidence have indicated
> > ancient Mars
> > had diverse environments with liquid water. However,
> > but these
> > rocks found by Curiosity could provide the type of
> > flow
> > information published this week. Curiosity's images of
> > conglomerate
> > rocks indicate that atmospheric conditions at Gale
> > once enabled
> > the flow of liquid water on the Martian surface.
> > During a two-year prime mission, researchers are using
> > Curiosity's 10
> > science instruments to assess the environmental history
> > Gale Crater
> > on Mars, where the rover has found evidence of ancient
> > environmental
> > conditions favorable for microbial life.
> > More information about Curiosity is online at:
> > http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and
> > http://mars.jpl.nasa.gov/msl/ .
> > You can follow the mission on Facebook at:
> > http://www.facebook.com/marscuriosity
> > on Twitter at
> > http://www.twitter.com/marscuriosity .
> > Guy Webster 818-354-6278
> > Jet Propulsion Laboratory, Pasadena, Calif.
> > guy.webster at jpl.nasa.gov
> > 2013-181
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Received on Fri 31 May 2013 04:57:00 AM PDT