The Earth’s magnetic field could have appeared due to the mantle, and not the core of the planet. This conclusion was made by geophysicists at the Scripps Institute of Oceanography at the University of California, San Diego during an exploration of the early Earth. The work was published on the service Science Direct.
According to geophysics, the Earth’s magnetic field exists due to the liquid outer core of the Earth. In 2007, French researchers proposed moving away from this theory, saying that the lower third of the early Earth’s mantle should also have been in a liquid state, the so-called “ocean of basal magma”.
Researchers Dave Stegman, Leah Ziegler and Nicholas Blanck note that scientists believe that the Earth’s mantle is a very poor electrical conductor, so if the lowest layer of the mantle was liquid, the movements inside it would not create such electric currents that are necessary to create a full magnetic field.
For the first time, a team of scientists used quantum mechanical calculations to predict the conductivity of a silicate fluid – of which the mantle could have composed – under the conditions of an ocean with basal magma. These calculations showed that this layer of the Earth could be very electrically conductive.
This means that the mantle could create the first magnetic protective layer on Earth, scientists say. In addition, such data can be used in the future to study tectonic shifts in the history of the Earth.
In addition, the appearance of a magnetic field precisely from the mantle, and not the nucleus, could lead to the fact that life on Earth appeared earlier than if it would have happened under other scenarios.