International geophysicists have discovered that giant anomalies in the Earth’s mantle have directly influenced the structure and strength of the planet’s magnetic field for at least the last 265 million years. These so-called LLSVP zones are colossal areas in the lower mantle beneath Africa and the Pacific Ocean, comparable in size to continents. The study results were published with the participation of the University of Liverpool.
Scientists explain that previously, Earth’s magnetic field was considered almost perfect and symmetrical, but the real picture has proved to be significantly more complex. Temperature differences at the mantle-core boundary cause the ‘hot’ mantle anomalies to partially disrupt the liquid core’s role in the geomagnetic dynamo. This directly affects local changes in the strength and direction of the magnetic field. Researchers arrived at these conclusions by comparing computer models with data on remanent magnetization of rocks formed over the last 23 million years.
Analysis showed that the recorded regional magnetic field fluctuations over hundreds of millions of years cannot be explained without considering the influence of LLSVP zones, which slow down the circulation of the molten core, thus forming Earth’s asymmetric magnetic field.
Recent studies have further illustrated the complexity of this phenomenon. Contemporary research suggests that these mantle anomalies could also be influencing tectonic activity. Experts emphasize that understanding these regions’ impact is crucial for comprehending the planet’s magnetic variations and geological behavior over geological timescales.
