I've received both of these releases this morning regarding talks to be
presented either today or last evening at the current Geological Society of
America meeting in Denver. Both are quite interesting (to me at least :-).
Because the list is so quiet, I thought I would go ahead and clog everyone's
mailbox with this material:
=======================================
MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
<A HREF="http://www.jpl.nasa.gov">http://www.jpl.nasa.gov</A>
Contacts: JPL/Guy Webster (818) 354-6278
University of Colorado/Jim Scott (303) 492-3114
IMAGE ADVISORY October 30, 2002
RED FRECKLES ON EUROPA SUGGEST 'LAVA LAMP' ACTION
Reddish spots on the icy surface of Jupiter's moon
Europa may indicate pockets of warmer ice rising from
below. This upwelling could provide an elevator ride to the
surface for material in an ocean beneath the ice, say
scientists studying data from NASA's Galileo spacecraft.
A Galileo color image of the spots, which are called
by the Latin term for freckles, "lenticulae," is being
presented at a conference this week by Colorado researchers
and is available online from NASA's Jet Propulsion
Laboratory at
<A HREF="http://photojournal.jpl.nasa.gov/catalog/PIA03878">
http://photojournal.jpl.nasa.gov/catalog/PIA03878</A> .
"Europa acts like a planetary lava lamp, carrying
material from near the surface down to the ocean, and, if
they exist, potentially transporting organisms up toward
the surface," said Dr. Robert Pappalardo, a planetary
scientist at the University of Colorado, Boulder.
The Galileo spacecraft, orbiting Jupiter since 1995,
has produced strong evidence that Europa has a deep ocean
of melted saltwater underneath a surface layer of ice.
Information about the mission and its discoveries is online
at
<A HREF="http://galileo.jpl.nasa.gov">http://galileo.jpl.nasa.gov</A> .
During the annual meeting of the Geological Society of
America, Oct. 27 through Oct. 30 in Denver, scientists are
discussing interpretations of Europa data and proposals for
future exploration of that world. A University of Colorado
press release about presentations there by Pappalardo and
colleagues is online at
<A HREF="http://www.colorado.edu/NewsServices/NewsReleases/2002/2054.html">
http://www.colorado.edu/NewsServices/NewsReleases/2002/2054.html</A> .
The Jet Propulsion Laboratory, a division of the
California Institute of Technology in Pasadena, manages
Galileo for NASA's Office of Space Science, Washington,
D.C. For more about Galileo, visit
<A HREF="http://galileo.jpl.nasa.gov">http://galileo.jpl.nasa.gov</A> .
=========================================
Geological Society of America
Denver, Colorado
Contact: Ann Cairns
Phone: 303-357-1056; Fax: 303-357-1074
[log in to unmask]
FOR IMMEDIATE RELEASE: October 29, 2002
GSA Release No. 02-46
A Moonwalker's Perspective 30 Years Later: Harrison Schmitt
to Offer "Shocking Revelations" at GSA Annual Meeting
The date was December 11, 1972, and the occasion was the
last Apollo mission to the Moon. Apollo 17 astronaut
Harrison Schmitt landed in the Valley of Taurus-Littrow,
the only scientist and the last of 12 men to step onto the
lunar surface. Standing in a brilliantly sun-lit valley
deeper than the Grand Canyon and gazing at a nearly full
Earth in a deep black sky, Schmitt's questions about the
origins of the Moon and terrestrial planets and their
subsequent history took on very personal significance.
Today, geoscientist Schmitt, literally one in six billion
human beings to combine science with actual lunar
exploration, continues to ponder those big questions.
He'll share some of the results of his synthesis of the
research of many others on Tuesday, Oct. 29, at the
annual meeting of the Geological Society of America in
Denver, CO. At the GSA Planetary Geology division's
Gilbert Lecture and Award Ceremony, Schmitt will discuss
"A Lunar Field Geologist's Perspective 30 Years Later:
Shocking Revelations about the Moon, Mars, and Earth."
Shocking? The orange "soil" or pyroclastic glass that
Schmitt found on the Moon, for example, continues to
provide clues about the origin of the Moon. In Schmitt's
view, it also reveals why the prevailing Giant Impact
hypothesis of the Moon's origins doesn't work.
"The major problem with this hypothesis," says Schmitt,
"is that the interior of the Moon is not cooperating. Most
importantly, the lower lunar mantle, based on analyses of
the Apollo 17 orange pyroclastic glass, has a chondritic,
that is, primordial elemental and isotopic imprint. This
primordial imprint would have disappeared or have been
significantly modified if the mantles of the Earth and
the impactor had already formed as required by the
current Giant Impact hypothesis.
According to Schmitt, "If the Giant Impact hypothesis
is not compatible with this evidence, alternatives to
it should be considered, including capture of a small,
independent planet from a solar orbit near that of the
Earth's."
Similarly, many scientists agree that the Moon's 50 or
so basins greater than 300km in diameter, as well as
most other ancient lunar craters, were formed at about
the same time by an apparent "cataclysm" 3.9 billion
years ago. According to Schmitt, "the primary argument
against this hypothesis is found in the sampling sites
for Apollo and lunar meteorite samples of impact-created
glass for which formation ages have been determined.
These samples have come largely from the surface of the
Moon most affected by the 14 youngest large basin-forming
impacts and debris thrown from them. These 14 youngest
impacts are, indeed, 3.9-3.8 billion years old based on
the dating of Apollo samples. A variety of volcanic and
impact evidence indicates that it is highly unlikely that
all the 35 or more older impact basins formed during the
same interval.
"One of the most exciting aspects of studying lunar
origin and evolution is applying that understanding to
the early Earth and Mars," says Schmitt. "And herein
lies a 'shocking' revelation about the possible origin
of Earth's first continents."
The 2500km diameter basin on the far-side of the Moon,
known as South Pole-Aitken, records an impact of an
extraordinarily energetic object near the end of the
period of smaller scale saturation cratering that followed
the solidification of the lunar crust. South Pole-Aitken
is just the most obvious manifestation of possibly three
or four other such huge early impacts, including the
3200km diameter front-side basin called Procellarum.
Schmitt estimates that the Procellarum basin formed at
about 4.3 b.y and South Pole-Aitken at about 4.2 b.y. If
these formation ages are in the ballpark, they suggest
an explanation for detrital zircon (ZrSiO4) crystals of
about the same ages in very old sedimentary rocks on
Earth. Early impacts of the scale of South Pole-Aitken
and Procellarum, occurring in water-rich environments
such as the Earth and Mars, would create thick sheets
of impact generated rock melt on a continental scale. As
these magma sheets crystallized, zirconium concentrations
may have reached levels that produced the very old zircons.
And what about Mars? Schmitt also suggests that there is
evidence for and reason to believe that Mars had both
early (older than 4.2 billion years) and late (younger
than 3.8 billion years) oceans due to separate periods
of intense volcanic eruptions that included abundant
water. The shores of these two oceans appear to have
been identified in the data returned by the Mars Surveyor
spacecraft now in orbit around that planet. Further, he
speculates that the most stable ecological niche for
Martian life has been the boundary between the subsurface
water ice zone and liquid water expected beneath that
zone. If simple, one cell life forms evolved on Mars in
parallel with their evolution on the Earth prior to 3.8
billion years ago, they may have adapted to survive in
this global niche as the surface of Mars became hostile
to any life.
"Extrapolating what we now know about the Moon and
applying it to Earth, Venus, Mars, and Mercury -- the
terrestrial planets -- is one of the primary scientific
returns of lunar research. But looking ahead, the Moon
will also mature our thinking about the gas giants and
other parts of the solar system," says Schmitt. For
example, whether as a result of a cataclysm or not,
where did the objects originate that created the 50
or more large basins on the Moon? He'll continue to
contribute to that work, this time with his feet firmly
planted on Earth, while developing a business rationale
to return to the Moon for its energy resources.
"A Lunar Field Geologist's Perspective 30 Years Later:
Shocking Revelations about the Moon, Mars, and Earth"
Harrison H. Schmitt
Gilbert Lecture – GSA Planetary Geology Division
Tuesday, Oct. 29, 6:00-7:00 p.m.
CONTACT INFORMATION
During the GSA Annual Meeting, Oct. 27-30, contact Christa
Stratton at the GSA Newsroom in the Colorado Convention
Center, Denver, Colorado, for assistance and to arrange for
interviews: (303) 228-8565.
Post-meeting contact information:
Harrison H. Schmitt
[log in to unmask]
505-823-2616
Ann Cairns
Director of Communications
Geological Society of America
[log in to unmask]
303-357-1056
=======================================
Wirt Atmar
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