thermoremanent magnetism

physics

Also known as: TRM, thermoremanent magnetization

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 14, 2026

Quick Summary

Thermoremanent magnetism (TRM) is a type of natural remanent magnetism found in rocks. It occurs when magnetic minerals within igneous rocks cool down past their Curie point. As they cool, the magnetic domains within these minerals align themselves with the Earth's magnetic field at that specific geological time, creating a permanent record of its orientation. This process is crucial for paleomagnetic studies, helping scientists understand past phenomena like polar wandering and continental drift. TRM is generally considered a stable and widespread form of magnetization, significant in both igneous and sedimentary rocks.12

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

oceanic crust
Marine magnetic anomalies
…of permanent magnetization is the thermoremanent magnetization (or TRM) of iron-titanium oxide minerals. These minerals lock in a TRM as they cool below 200–300 °C (392–572 °F) in the presence of Earth’s magnetic field. Although several processes are capable of altering the TRM, including reheating and oxidation at the seafloor,…
Read More
…of permanent magnetization is the thermoremanent magnetization (or TRM) of iron-titanium oxide minerals. These minerals lock in a TRM as they cool below 200–300 °C (392–572 °F) in the presence of Earth’s magnetic field. Although several processes are capable of altering the TRM, including reheating and oxidation at the seafloor,…
Read More

remanent magnetism
…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 its orientation.
Read More
…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 its orientation.
Read More

rock
Types of remanent magnetization
TRM (thermoremanent magnetization) occurs when a substance is cooled, in the presence of a magnetic field, from above its Curie temperature to below that temperature. This form of magnetization is generally the most important, because it is stable and widespread, occurring in igneous and sedimentary rocks.…
Read More
TRM (thermoremanent magnetization) occurs when a substance is cooled, in the presence of a magnetic field, from above its Curie temperature to below that temperature. This form of magnetization is generally the most important, because it is stable and widespread, occurring in igneous and sedimentary rocks.…
Read More