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Crustal Magnetic FieldsCosmos 49, Polar Orbit Geophysical Observatory (POGO) (Orbiting Geophysical Observatory (OGO-2, 4 and 6)) and Magsat have been the only low-earth orbiting satellites to measure the crustal magnetic field on a global scale. These missions revealed the presence of long- wavelength (> 500 km) crustal anomalies predominantly located over continents. Ground based methods were, for the most part, unable to record these very large-scale features; no doubt due to the problems of assembling continental scale maps from numerous smaller surveys acquired over many years. Questions arose as to the source and nature of these long-wave length anomalies. As a result there was a great stimulant given to the study of the magnetic properties of the lower crust and upper mantle. Some indication as to the nature of these deep sources has been provided by the recent results from the deep crustal drilling programs. In addition, the mechanism of magnetization, induced or remanent, was largely unknown. For computational ease these anomalies were considered to result solely from induced magnetization. However, recent results from Mars Orbiter Laser Altimeter (MOLA), a magnetometer-bearing mission to Mars, have revealed crustal anomalies with dimensions similar to the largest anomalies on Earth. These Martian features could only have been produced by remanent magnetization, since Mars lacks an inducing field. The origin of long-wavelength crustal anomalies, however, has not been completely determined. Several large crustal magnetic anomalies (e.g., Bangui, Kursk, Kiruna and Central Europe) will be discussed and the role of future satellite magnetometer missions (Orsted, SUNSAT and Champ) in their interpretation evaluated.
Document ID
19990092489
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Taylor, Patrick T.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Ravat, D.
(University of Southern Illinois Carbondale, IL United States)
Frawley, James J.
(Herring Bay Geophysics, Inc. Dunkirk, MD United States)
Date Acquired
August 19, 2013
Publication Date
July 19, 1999
Subject Category
Geophysics
Meeting Information
Meeting: International Union of Geodesy and Geophysics General Assembly
Location: Birmingham
Country: United States
Start Date: July 19, 1999
End Date: July 30, 1999
Sponsors: International Union of Geodesy and Geophysics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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