Our planet’s magnetic field, which some animals use for navigating, is constantly changing. According to experts, the sources of Earth’s magnetic field are its core and its crust. The Earth’s mantle, which basically is what’s between the crust and the core, is believed to be magnetically dead. Also, the deep regions of our planet’s metal interior lack magnetic properties due to the high temperatures and pressures.
However, an international team of researchers recently discovered that a component of our planet’s mantle, hematite, an iron oxide, can retain its magnetic properties. This phenomenon happens especially in colder tectonic plates, also known as slabs, which are found prominently under the western Pacific Ocean. The study was published in Nature.
Ilya Kupenko, the first author of the study, highlighted that this discovery could prove to be extremely helpful for future studies of magnetic anomalies on the Earth and other planets. Now, scientists decided to analyze the sources of Earth’s magnetism even more, by measuring the properties of iron oxides at the “transition zone” of the mantle, which separates the upper and the lower mantle of the planet.
Research Shows That The Earth’s Mantle Has Magnetic Properties
Below you can see an illustration of the interior of the Earth. The blue dotted lines represent the magnetic field. On the right side is an illustration of the experiment that the scientists conducted. They took samples of hematite and pressed and heated them between two diamonds. This simulates the conditions in the Earth’s mantle. Doing this, they confirmed that these conditions trigger the magnetic properties of the iron oxide.
The Earth’s magnetism is usually observed through data gathered by satellites or by studying rocks. As some of you may know already, our planet’s geomagnetic poles are moving. In the last decades, scientists reported an acceleration in this movement.
The discovery made on the magnetic properties of the Earth’s mantle could prove to be useful for future studies about the movement of the geomagnetic poles.