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NASA
SCIENTISTS DETERMINED TO UNEARTH ORIGIN OF THE ITURRALDE CRATER
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1 | | | NASA
scientists will venture into an isolated part of the Bolivian Amazon to try and
uncover the origin of a 5 mile (8 kilometer) diameter crater there known as the
Iturralde Crater. Traveling to this inhospitable forest setting, the Iturralde
Crater Expedition 2002 will seek to determine if the unusual circular crater was
created by a meteor or comet. Organized
by Dr. Peter Wasilewski of NASA's Goddard Space Flight Center, Greenbelt, Md.,
the Iturralde Crater Expedition 2002 will be led by Dr. Tim Killeen of Conservation
International, which is based in Bolivia. Killeen will be assisted by Dr. Compton
Tucker of Goddard.
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2 | | | The
team intends to collect and analyze rocks and soil, look for glass particles that
develop from meteor impacts and study magnetic properties in the area to determine
if the Iturralde site, discovered in the mid-1980s with satellite imagery, was
indeed created by a meteor. If
a meteorite is responsible for the impression, rocks in the area will have shock
features that do not develop under normal geological circumstances. The team will
also look for glass particles, which develop from the high temperatures of impact.
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3 | | | The
Iturralde Crater Expedition 2002 team will extensively analyze soil in the impact
zone for confirmation of an impact. One unique aspect of the Iturralde site is
the 4-5 km deep surface sediment above the bedrock. Thus the impact was more of
a gigantic "splat" rather than a collision into bedrock. The
large crater is only 1 meter lower in elevation than the surrounding area. Water
collects within the depression, but not on the rim of the crater, which is slightly
higher than both the surrounding landscape and the interior of the crater. These
subtle differences in drainage are reflected in the forest and grassland habitats
that developed on the landscape. It is precisely these differences in the vegetation
structure that can be observed from space and which led to the identification
of the Iturralde Crater in the 1970s when Landsat Images first became available
for Bolivia.
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4 | | | Impact
craters can also be confirmed through the magnetic study of the impact zone. Dr.
Wasilewski's team will conduct ground magnetometer surveys and will examine the
area through an unmanned aerial vehicle plane fitted with a magnetometer, an instrument
for measuring the magnitude and direction of magnetic field. The resulting data
will be analyzed by associating the magnetic readings with geographical coordinates,
to map magnetic properties of the area. The magnetometer data could provide conclusive
evidence as to whether or not the Iturralde feature is an impact crater.
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The
Iturralde Crater Expedition 2002 expedition also contains
an education component. Teachers from around the world who
are involved with the teacher professional development program,
called Teacher as Scientist, have helped to design the expedition.
One teacher will actually be on-site assisting with data collection.
University
students from Bolivia will also be involved in the expedition.
The educational element of the expedition is just as important
as the science results," said Goddard engineer Patrick
Coronado. "This is one of those experiments that stirs
the imagination, where science and technology come head-to-head
with nature in an attempt to unlock its secrets."
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Image
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Caption
for Image 6 / animation:
ITURRALDE STRUCTURE VISUALIZATION
This
Landsat image shows the 8 km circular Iturralde Structure
that resembles a meteor impact on the eastern Bolivian landscape.
The Iturralde Structure is located in perhaps the most remote
and wildest part of the Bolivian lowlands. The crater is situated
on the boarder of the Amazon forest and the vast open savannas
of eastern Bolivia.
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Caption
for Image 7 / animation:
Image
7: MAGPLANE IMAGE The
MAGPLANE is a one-third scale, remote controlled model of
a 1930 Piper Cub airplane. It is outfitted with a magnetometer,
auto-pilot, GPS, onboard computer and a satellite communication
system and will be used to remotely collect data of the magnetic
signature in and around the Iturralde Structure. Click
here for an enlargement of this image.
Animation:
MAGPLANE FLIGHT PATH VISUALIZATION
The MAGPLANE will take off from a dirt runway at Porta Araona,
within the Bolivian jungle under the remote control of an
operator. After an in-flight checkout, the remote system will
be turned off and the onboard autopilot will fly the plane
through the preprogrammed flight path at an altitude of about
200ft. The plane's instruments will record the magnetometer
data and simultaneously transmit the data via satellite for
researchers in Bolivia and the United States. After completing
its flight plan, the MAGPLANE will return to the launch site,
where the operator will reclaim remote control and land the
plane. It may take several days to complete the planned magnetic
survey flight plan shown in this visualization.
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Caption
for Image 8 / animation: GLOBAL
DISPERSION OF VERIFIED IMPACT CRATERS
Approximately
150 geological structures have been verified as meteor impact
craters on the Earth. It is estimated that several hundred
more remain to be identified. This visualization shows the
distribution of verified impact structures across the globe.
The small dots represent impact crater diameters of .02 -
20km in diameter. The medium size dots represent impact crater
diameters of 20 - 100 km in diameter. The largest dots represent
impact craters of 100 - 300 km in diameter.
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