Encyclopedia of Scientific Dating Methods

Living Edition
| Editors: W. Jack Rink, Jeroen Thompson

Magnetic Anomalies

  • Roi Granot
Living reference work entry
DOI: https://doi.org/10.1007/978-94-007-6326-5_137-1

Definition

A magnetic anomaly is the magnetic field remaining after the Earth’s magnetic field has been removed from the observed amplitude of the local magnetic field. The remanent magnetization of rocks records past variations of the geomagnetic field whereby spatial changes in their magnetization give rise to magnetic anomalies. We can date the oceanic crust by studying the unique pattern of lineated positive and negative magnetic anomalies that arise due to past reversals of the geomagnetic field with known age. Besides the primary signal that is related to past polarity reversals, the shape and tiny variations (wiggles) of the anomalies can be used to further constrain the age of the crust. Altogether, magnetic anomalies provide the main source of dating for the oceanic basins and lay the foundations for global plate reconstructions which place important constraints on the development of the lithosphere, biosphere, hydrosphere, cryosphere, and global climate.

Introduction

The...

Keywords

Source Rock Oceanic Crust Magnetic Anomaly Outer Core Seafloor Spreading 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  1. 1.Department of Geological and Environmental SciencesBen Gurion University of the NegevBeer ShevaIsrael