[meteorite-list] NASA Scientists Determined To Unearth Origin Of The Iturralde Crater

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:21 2004
Message-ID: <200209041727.KAA17501_at_zagami.jpl.nasa.gov>

http://www.gsfc.nasa.gov/topstory/20020904icecrater.html

NASA SCIENTISTS DETERMINED TO UNEARTH ORIGIN OF THE ITURRALDE CRATER
Goddard Space Flight Center
September 4, 2002

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.

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.

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.

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.

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."
Received on Wed 04 Sep 2002 01:27:48 PM PDT