[meteorite-list] Evidence Of Martian Land Of Lakes Discovered

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:37:31 2004
Message-ID: <200012042048.MAA20078_at_zagami.jpl.nasa.gov>

Donald Savage
Headquarters, Washington, DC December 4, 2000
(Phone: 202/358-1727)

Mary Hardin
Jet Propulsion Laboratory, Pasadena, CA
(Phone: 818/354-0344)

RELEASE: 00-190

EVIDENCE OF MARTIAN LAND OF LAKES DISCOVERED

     In what ultimately may be their most significant discovery
yet, Mars scientists say high-resolution pictures showing layers of
sedimentary rock paint a portrait of an ancient Mars that long ago
may have featured numerous lakes and shallow seas.

"We see distinct, thick layers of rock within craters and other
depressions for which a number of lines of evidence indicate that
they may have formed in lakes or shallow seas. We have never before
had this type of irrefutable evidence that sedimentary rocks are
widespread on Mars," said Dr. Michael Malin, principal investigator
for the Mars Orbiter Camera on NASA's Mars Global Surveyor
spacecraft at Malin Space Science Systems (MSSS), San Diego, CA.
"These images tell us that early Mars was very dynamic and may have
been a lot more like Earth than many of us had been thinking."

Such layered rock structures where there were once lakes are common
on Earth. The pancake-like layers of sediment compressed and
cemented to form a rock record of the planet's history.

The regions of sedimentary layers on Mars are spread out and
scattered around the planet. They are most common within impact
craters of Western Arabia Terra, the inter-crater plains of
northern Terra Meridiani, the chasms of the Valles Marineris, and
parts of the northeastern Hellas Basin rim. The scientists compare
the rock layers on Mars to features seen in the American Southwest,
such as the Grand Canyon and the Painted Desert of Arizona.

"We caution that the Mars images tell us that the story is actually
quite complicated and yet the implications are tremendous. Mars has
preserved for us, in its sedimentary rocks, a record of events
unlike any that occur on the planet today," said Dr. Ken Edgett,
staff scientist at MSSS. "This is changing the way we think about
the early history of Mars -- a time perhaps more than 3.5 billion
years ago."

"On Earth, sedimentary rocks preserve the surface history of our
planet, and within that history, the fossil record of life. It is
reasonable to look for evidence of past life on Mars in these
remarkably similar sedimentary layers," said Malin. "What is new in
our work is that Mars has shown us that there are many more places
in which to look, and that these materials may date back to the
earliest times of Martian history."

Malin added, "I have not previously been a vocal advocate of the
theory that Mars was wet and warm in its early history. But my
earlier view of Mars was really shaken when I saw our first high-
resolution pictures of Candor Chasma. The nearly identically thick
layers would be almost impossible to create without water."

As an alternative to lakes, Malin and Edgett suggest that a denser
atmosphere on early Mars could have allowed greater amounts of
windborne dust to settle out on the surface in ways that would have
created the sedimentary rock.

"We have only solved one little piece of a tremendous puzzle,"
Malin said. "There is no illustration on the box to show us what it
is supposed to look like when it is completed and we are sure most
of the pieces are missing."

"These latest findings from the Mars Global Surveyor tell us that
more study both from orbit and at the surface is needed to decipher
the tantalizing history of water on Mars," said Dr. Jim Garvin,
Mars Exploration Program Scientist at NASA Headquarters. "Our
scientific strategy of following the water by seeking, conducting
in situ studies, and ultimately sampling will follow up on these
latest discoveries about Mars, and adapt to the new understanding."

"Mars seems to continually amaze us with unexpected discoveries,"
said Dr. Edward Weiler, Associate Administrator for Space Science
at NASA Headquarters. "This finding just might be the key to
solving some of the biggest mysteries on Mars, and it also tells us
that our new Mars exploration program needs the flexibility to
follow up in a carefully thought-out manner."

"The finding of layered sedimentary deposits is something that
biologists have been hoping for," said Dr. Ken Nealson, director of
the Center for Life Detection at NASA's Jet Propulsion Laboratory
(JPL), Pasadena, CA. "Perhaps the favorite sites for biologists to
search for fossils or evidence of past life on Earth are layered
lake or oceanic sediments such as in these sites Malin and Edgett
describe."

The Mars Global Surveyor mission is managed by JPL for NASA's
Office of Space Science, Washington, DC. Malin Space Science
Systems built and operates the camera system. Lockheed Martin
Astronautics, Denver, CO, developed and operates the spacecraft.

Images for this release are available at:

      http://www.msss.com/mars_images/moc/dec00_seds/

Information on the Mars Global Surveyor is available at:

                 http://mars.jpl.nasa.gov/mgs

                               - end -
Received on Mon 04 Dec 2000 03:48:12 PM PST