What does paleomagnetism mean?
Paleomagnetism is the study of magnetic traces preserved in rocks, sediments and other materials. Minerals such as magnetite can acquire magnetic properties as they form or cool, retaining a record of the direction and intensity of the magnetic field at that time. By comparing these records, scientists can reconstruct changes in Earth's magnetic field, identify ancient magnetic poles and investigate the movement of continents. The discipline also contributes to the study of plate tectonics, geological chronology and the development of the Earth. Its name reflects its focus on the distant past: the prefix "paleo-" refers to ancient conditions, while "magnetism" identifies the magnetic properties under investigation. Although often associated with the movement of tectonic plates, paleomagnetism provides evidence for a wider range of questions about Earth's history, including magnetic reversals and the relative positions of landmasses millions of years ago.
nounThe branch of geophysics that studies ancient magnetic fields preserved in rocks and other materials, especially the history of Earth's magnetic field. It uses the magnetic records retained by minerals to reconstruct past changes in geomagnetic polarity and orientation.
- The study of magnetic properties preserved in rocks and other materials as records of ancient geomagnetic fields.
"Paleomagnetism helped the researchers determine where the ancient rocks had been located relative to Earth's magnetic poles."
"Measurements of the paleomagnetism in cooling rocks revealed a reversal of Earth's magnetic field."
"Paleomagnetic evidence supported the hypothesis that the continents have shifted over geological time."
The term is usually uncountable; the plural is rare and generally used when referring to separate recorded magnetic signatures or studies.
"The researchers compared paleomagnetisms obtained from two different rock formations."
Paleomagnetism turns ancient rock into a compass frozen in time, preserving evidence of where it formed and how Earth's magnetic poles have moved.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of paleomagnetism
The word combines the combining form "paleo-", from Greek palaios meaning "old" or "ancient", with "magnetism", which derives from "magnet" and ultimately from the Greek magnētis. "Paleomagnetism" developed as the scientific study of magnetism preserved in ancient geological materials. Related words include "magnetic", "magnetize" and "magnetism", while the same ancient prefix appears in "paleontology".
Related word forms
How paleomagnetism is actually used
This is a specialist scientific term used chiefly in geophysics, geology, palaeontology and related fields. In British spelling, the variant "palaeomagnetism" is also common.
Easily confused with paleomagnetism
Geomagnetism concerns Earth's magnetic field, whereas paleomagnetism reconstructs its ancient history from magnetic traces preserved in rocks and sediments.