A team of geologists recently made a groundbreaking discovery about the Earth’s magnetic field. They found two massive, hot structures lying deep beneath the surface that have influenced this magnetic field for over 265 million years.
These structures, called large low-shear-velocity provinces (LLSVPs), are enormous—each roughly the size of Africa. They sit around 2,900 kilometers below Earth’s surface and are quite different from the solid rock layers we typically envision. Instead, they are areas within the mantle where the material is hotter and denser, surrounded by cooler zones that speed up seismic waves.
Scientists have been aware of these anomalies since the 1970s, but only recently have they confirmed the LLSVPs’ significant role in shaping the magnetic field. A recent study published in Nature Geoscience reveals that the temperature differences between these hot zones and the surrounding mantle affect how liquid iron flows in the Earth’s core. This movement generates the planet’s magnetic field.
The researchers used supercomputers to run simulations that compared a uniform mantle to one with LLSVPs. The results showed that the model with the LLSVPs matched the actual irregularities in Earth’s magnetic field, highlighting the influence these structures have.
Interestingly, some parts of the magnetic field have remained stable for hundreds of millions of years, while others have changed rapidly. This leads to important questions about the Earth’s history, including the formation of ancient continents like Pangaea and the climate conditions of that era.
Andy Biggin, a geomagnetism expert at the University of Liverpool and a study author, stated, “Our findings challenge the idea that Earth’s magnetic field behaves like a perfect bar magnet aligned with the planet’s rotation.”
This discovery does more than just reshape our understanding of geology; it impacts how we think about Earth’s past. As we learn more about these hidden structures, we gain valuable insights into everything from climate to the distribution of natural resources.
For more detailed insights on these findings, you can read the full study here or check out the announcement from the University of Liverpool here.
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