[meteorite-list] NASA, Planetary Scientists Find Meteoritic Evidence of Mars Water Reservoir

From: Galactic Stone & Ironworks <*meteoritemike_at_meteoritecentral.com*> Date: Thu, 18 Dec 2014 18:50:32 -0500 Message-ID: <CAKBPJW_sm+cb_p7-rGwY33phEdiNTABZ+jS7euRJV3uY63asYA_at_mail.gmail.com> · meteoritemike_at_meteoritecentral.com

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On 12/18/14, Ron Baalke via Meteorite-list
<meteorite-list at meteoritecentral.com> wrote:
>
>
> December 18, 2014
>
> NASA, Planetary Scientists Find Meteoritic Evidence of Mars Water Reservoir
>
>
> NASA and an international team of planetary scientists have found evidence
> in
> meteorites on Earth that indicates Mars has a distinct and global reservoir
>
> of water or ice near its surface.
>
> Though controversy still surrounds the origin, abundance and history of
> water
> on Mars, this discovery helps resolve the question of where the "missing
> Martian water" may have gone. Scientists continue to study the planet's
> historical record, trying to understand the apparent shift from an early wet
>
> and warm climate to today's dry and cool surface conditions.
>
> The reservoir's existence also may be a key to understanding climate
> history and the potential for life on Mars. The team's findings are
> reported in the journal Earth and Planetary Science Letters.
>
> "There have been hints of a third planetary water reservoir in previous
> studies of Martian meteorites, but our new data require the existence of a
> water or ice reservoir that also appears to have exchanged with a diverse
> set
> of Martian samples," said Tomohiro Usui of Tokyo Institute of Technology in
>
> Japan, lead author of the paper and a former NASA/Lunar and Planetary
> Institute postdoctoral fellow. "Until this study there was no direct
> evidence for this surface reservoir or interaction of it with rocks that
> have
> landed on Earth from the surface of Mars."
>
> Researchers from the Tokyo Institute of Technology, the Lunar and Planetary
>
> Institute in Houston, the Carnegie Institution for Science in Washington and
>
> NASA's Astromaterials Research and Exploration Science Division, located at
>
> the agency's Johnson Space Center in Houston, studied three Martian
> meteorites.
>
> The samples revealed water comprised of hydrogen atoms that have a ratio of
>
> isotopes distinct from that found in water in the Red Planet's mantle and
> current atmosphere. Isotopes are atoms of the same element with differing
> numbers of neutrons.
>
> While recent orbiter missions have confirmed the presence of subsurface ice,
>
> and melting ground-ice is believed to have formed some geomorphologic
> features on Mars, this study used meteorites of different ages to show that
>
> significant ground water-ice may have existed relatively intact over time.
>
> Researchers emphasize that the distinct hydrogen isotopic signature of the
> water reservoir must be of sufficient size that it has not reached isotopic
>
> equilibrium with the atmosphere.
>
> "The hydrogen isotopic composition of the current atmosphere could be fixed
>
> by a quasi-steady-state process that involves rapid loss of hydrogen to
> space
> and the sublimation from a widespread ice layer," said coauthor John Jones,
>
> a JSC experimental petrologist and member of NASA's Mars Curiosity rover
> team.
>
> Curiosity's observations in a lakebed, in an area called Mount Sharp,
> indicate Mars lost its water in a gradual process over a significant period
>
> of time.
>
> "In the absence of returned samples from Mars, this study emphasizes the
> importance of finding more Martian meteorites and continuing to study the
> ones we have with the ever-improving analytical techniques at our
> disposal," said co-author Conel Alexander, a cosmochemist at the Carnegie
> Institution for Science.
>
> In this investigation, scientists compared water, other volatile element
> concentrations and hydrogen isotopic compositions of glasses within the
> meteorites, which may have formed as the rocks erupted to the surface of
> Mars
> in ancient volcanic activity or by impact events that hit the Martian
> surface, knocking them off the planet.
>
> "We examined two possibilities, that the signature for the newly identified
>
> hydrogen reservoir either reflects near surface ice interbedded with
> sediment
> or that it reflects hydrated rock near the top of the Martian crust," said
> coauthor and JSC cosmochemist Justin Simon. "Both are possible, but the
> fact that the measurements with higher water concentrations appear
> uncorrelated with the concentrations of some of the other measured volatile
>
> elements, in particular chlorine, suggests the hydrogen reservoir likely
> existed as ice."
>
> The information being gathered about Mars from studies on Earth, and data
> being returned from a fleet of robotic spacecraft and rovers on and around
> the Red Planet, are paving the way for future human missions on a journey to
>
> Mars in the 2030s.
>
> These findings can be viewed online in their entirety at:
>
> http://go.nasa.gov/1zwSjTa
>
> For more about the ARES Division at JSC, visit:
>
> http://ares.jsc.nasa.gov
>
> Learn about NASA's Journey to Mars at:
>
> http://www.nasa.gov/content/nasas-journey-to-mars/
>
>
> -end-
>
> Dwayne Brown
> Headquarters, Washington
> 202-358-1726
> dwayne.c.brown at nasa.gov
>
> William Jeffs
> Johnson Space Center, Houston
> 281-483-5111
> william.p.jeffs at nasa.gov
>
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