natural remanent magnetism

physics

Also known as: NRM

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Last updated

June 17, 2026

Quick Summary

Natural remanent magnetism (NRM) is the permanent magnetism found in rocks, which reflects the Earth's magnetic field orientation at the time the rock formed. This phenomenon is crucial for paleomagnetic studies, such as understanding polar wandering and continental drift.1

There are several ways rocks acquire NRM:
* Thermo-remanent magnetism (TRM): Occurs when magnetic minerals in igneous rocks cool below their Curie point, aligning with the Earth's magnetic field.1
* Detrital remanent magnetism (DRM): Happens when magnetic mineral grains in sedimentary rocks align with the Earth's field during deposition before the rock solidifies.1
* Chemical remanent magnetism (CRM): Develops when nonmagnetic minerals chemically alter into magnetic ones, which then align with the ambient magnetic field.2
* Viscous magnetization (VRM): A weaker, unstable magnetization acquired slowly over time due to thermal agitation in the Earth's magnetic field.2

These different types of remanent magnetism can be identified, allowing scientists to interpret a rock's magnetic history.12

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Types of remanent magnetization
NRM (natural remanent magnetization) is the magnetization detected in a geologic in situ condition. The NRM of a substance may, of course, be a combination of any of the other remanent magnetizations described here.
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NRM (natural remanent magnetization) is the magnetization detected in a geologic in situ condition. The NRM of a substance may, of course, be a combination of any of the other remanent magnetizations described here.
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remanent magnetism
…several natural processes, generally termed natural remanent magnetism, the most important being thermo-remanent magnetism. This arises when magnetic minerals forming in igneous rocks cool through the Curie point and when the magnetic domains within the individual minerals align themselves with the Earth’s magnetic field, thus making a permanent record of…
Read More
…several natural processes, generally termed natural remanent magnetism, the most important being thermo-remanent magnetism. This arises when magnetic minerals forming in igneous rocks cool through the Curie point and when the magnetic domains within the individual minerals align themselves with the Earth’s magnetic field, thus making a permanent record of…
Read More