The Earth’s mantle has long been believed to be a fast-flowing and well-mixed region by many seismologists and researchers. However, a recent study from researchers at Utrecht University in the Netherlands challenges this theory. Their findings come from the discovery of two sunken, continent-sized geological islands located inside a tectonic plate graveyard 1,800 feet below the Earth’s surface.
Published in the journal Nature, the study focuses on the tones generated during large earthquakes that cause the Earth to vibrate. By analyzing these acoustic signatures, seismologists can study the planet’s interior and identify anomalies based on the tuning and volume of the vibrations.
Over 25 years ago, researchers discovered the presence of two underground “super-continents” beneath Africa and the Pacific Ocean. These formations, known as Large Low Seismic Velocity Provinces (LLSVPs), exist near the boundary between the Earth’s mantle and core. The study’s co-author, Arwen Deuss, explained that these islands are surrounded by a graveyard of tectonic plates that have been transported there through the process of subduction.
The study focused on the ability of LLSVPs to dampen seismic waves, which is influenced by their temperature and mineral composition. Contrary to expectations, the researchers found little damping in the LLSVPs, indicating a hotter temperature and larger grain sizes. This suggests that the LLSVPs are much older than previously thought, possibly over 500 million years old, and more rigid, resisting the flow of the mantle.
The discovery challenges the traditional view of a fluid and well-mixed mantle and has implications for our understanding of Earth’s planetary evolution, as well as the inner workings of volcanoes and mountains. By studying these massive formations, researchers can gain insights into how the Earth’s mantle drives geological phenomena like mantle plumes, which are large pockets of molten material that rise from deep within the Earth. Mantle plumes are hot and narrow columns of rock that rise from the Earth’s mantle to the surface. These plumes play a crucial role in causing volcanic eruptions. According to Duess, a scientist studying these phenomena, mantle plumes are believed to originate at the edges of Large Low Shear Velocity Provinces (LLSVPs).
Once near the surface, these mantle plumes can trigger volcanic activity. The intense heat and pressure from the rising plumes can melt rock and create magma chambers beneath the Earth’s crust. As the pressure builds up, it can lead to volcanic eruptions, releasing molten lava, ash, and gases into the atmosphere.
Understanding the origins and behavior of mantle plumes is essential for predicting and monitoring volcanic activity. Scientists study seismic waves and geological data to track the movement of mantle plumes and assess the risk of potential eruptions in volcanic regions.
In conclusion, mantle plumes are fascinating geological features that play a key role in shaping our planet’s surface. By studying these plumes, scientists can gain valuable insights into the inner workings of the Earth and improve our ability to forecast volcanic eruptions.
