Encyclopedia of Geomagnetism and Paleomagnetism

2007 Edition
| Editors: David Gubbins, Emilio Herrero-Bervera

Magnetic Anomalies, Marine

  • James R. Heirtzler
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-4423-6_173

Magnetic anomalies are perturbations of the geomagnetic field due to Earth structure. They are seen when one subtracts a regional magnetic field from a series of observed readings. They have a different character over surface of the deep oceans than on they do on land. The unique nature of marine magnetic anomalies became apparent in the early 1950s when submarine detecting magnetometers were used for geophysical exploration by research ships. Over the oceans important marine anomalies may have an amplitude of a few tens to a few hundreds nanotesla and a wavelength of about 100 km, depending upon the depth of water. Previously some geomagnetic field measurements had been made on nonmagnetic ships but these readings were taken so far apart that the short anomalies were not defined. A few aircraft measurements had been made but they were high above the ocean surface reducing the size of the anomaly or were made over the continental shelf where anomalies have a different character from...

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Bibliography

  1. Cande, S.C., and Kent, D.V., 1995. Revised calibration of the geomagnetic polarity timescale for the late Cretaceous and Cenozoic. Journal of Geophysical Research, 100: 6093–6095.CrossRefGoogle Scholar
  2. Heirtzler, J.R., LePichon, and Xavier Gregory, B.J., 1966. Magnetic anomalies over the Reykjanes Ridge. Deep‐Sea Research, 13: 427–443.Google Scholar
  3. Muller, R.D., Roest, W.R., Royer, Y.‐Y., Gahagan, L.M., and Sclater, J.G., 2005. Digital isochrons of the ocean floor. Available at: htto://gdcinfo.agg.nrcan.gc.ca/app/images/agemap.gif
  4. Vacquier, V.V., 1959. Measurement of horizontal displacements along faults in the ocean floor. Nature, 183: 452–453.CrossRefGoogle Scholar
  5. Vine, F.J., and Matthews, D.H., Magnetic anomalies over oceanic ridges. Nature, 199: 947–949.Google Scholar

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© Springer-Verlag 2007

Authors and Affiliations

  • James R. Heirtzler

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