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May 17, 2004
NASA and USGA Magnetic Database
“Rocks” the World
NASA and the United States Geological
Survey (USGS) are teaming up to create one of the
most complete databases of magnetic properties of
Earth’s rocks ever assembled. The
partnership demonstrates ongoing interagency
collaboration.
Satellite data of Earth’s magnetic field
combined with rock magnetic data collected on the
ground will provide more complete insight into
Earth’s geology, gravity and magnetism.
Satellites, including NASA’s Magsat,
have detected magnetic signals in the upper layer
of the Earth, called the lithosphere. With over
36,000 rock samples, the combined database will
help researchers determine the origin of these
signals in Earth’s crust.
The database will be available to the public via
the Internet. A clickable map of the world will
include locations where detailed rock magnetic
data were collected.
Open access to specific properties and
locations of each type of rock will allow
researchers to more accurately model
Earth’s gravity and magnetic fields. This
should improve our understanding of the structure
and development of Earth’s crust.
“The information in this database will
allow more realistic interpretations of satellite
magnetic data and will contribute to a variety of
studies such as groundwater, mineral resource,
and earthquake hazard investigations,” said
Katherine Nazarova, a researcher at NASA Goddard
Space Flight Center (GSFC) who is coordinating
the collaborative effort with Jonathan Glen from
the USGS.
The NASA GSFC database contains magnetic
properties of 19,000 samples. The samples come
from all over the world including the Ukrainian
and Baltic shields, Kamchatka, the Ural Mountains
and Iceland.
2000 Icelandic rocks in the database have
helped explain the source of unusual magnetic
activity in Iceland recorded by both Magsat and
German Champ missions. Database records revealed
the magnetic shifts in Iceland were caused by
ferrobasalts, analogues to Martian rocks. As
researchers continue to study Mars, these
findings may shed light on Mars’ geology.
The USGS database contains rock densities and
magnetic properties for some 17,000 entries. Many
of these data were taken from surface outcrops in
the Western U.S. They span a broad range of rock
types.
Researchers collect rock specimens and data in
a variety of ways. Research vessels are used to
dredge samples from the ocean floor. Ships may
also carry huge deep-sea drills that pull cores
of sediment and rock from the beneath the ocean.
The database includes rock magnetic data from the
deepest borehole in the world. It was drilled in
northern Russia in the Baltic Shield. Researchers
drilled and extracted cores from the continental
crust as deep as 12.26 kilometers (7.62 miles).
On land, scientists may collect samples from
rock outcrops. When rocks have been exposed to
the elements, researchers use small hand drills
to uncover fresh material under a rock’s
surface.
Satellites that have detected unexplained
variations in Earth’s magnetic field
include NASA’s Magsat and Polar Orbiting
Geophysical Observatory, Germany’s Champ
satellite, and the Danish Oersted satellite.
The combined USGS and GSFC databases and
future updates will eventually be available and
maintained through the National Oceanic and
Atmospheric Administration at the World Data
Center A in Boulder, Colorado.
Nazarova will present a poster describing the
database at the 2004 Joint Assembly of the
American Geophysical Union taking place this week
in Montreal, Canada.
The mission of NASA’s Earth Science
Enterprise is to develop a scientific
understanding of the Earth System and its
response to natural or human-induced changes to
enable improved prediction capability for
climate, weather, and natural hazards.
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Contacts:
Krishna Ramanujan
krishna_ramanujan@ssaihq.com
NASA Goddard Space Flight Center
Phone: 607-273-2561
Scott Harris
sharris@usgs.gov
United States Geological Survey
Phone: 703-648-4054
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Band Iron Formations
These Band Iron formations are precambrian
sedimentary rocks. They are highly magnetic. Band
Iron Formations like this one were responsible
for prominent variations in Earth’s
magnetic field, like the Kursk Magnetic Anomaly
that was remotely sensed by satellites. Kursk is
located in western Russia, at the confluence of
the Seym and Tuskar rivers. Credit: Photo
courtesy of P.Hoffman
Lithospheric Magnetic
Anomalies
This image shows variations in magnetic fields
in the upper layer of Earth’s surface known
as the lithosphere. The data were acquired by
satellites passing over at an altitude of 400 km.
The satellite data were run through a model to
produce this image. The units are in nanoteslas,
the common unit for measuring magnetic fields.
The color bar indicates areas with positive and
negative magnetic fields. Credit: Terrence Sabaka
et al./NASA GSFC
NASA Map for Rock Magnetic Data
Locations
This image shows a map for rock magnetic data
locations found in the NASA Goddard Space Flight
Center magnetic database. NASA’s database
contains 19,000 samples. Credit: K. Nazarova/NASA
GSFC
USGS Rock Magnetic Data
Locations
This image shows a map for rock magnetic data
locations found in the USGS magnetic database.
USGS’s database contains 17,000 samples.
Credit: J. Glen/USGS
High-Resolution
Image
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