Beneath the surface of the Earth are many secrets that scientists are trying to uncover with the help of new technology. One such mystery is the two giant structures found in the Earth’s interior. These mysterious clots occupy between 3 and 9 percent of the Earth’s surface and are located beneath Africa and the Pacific Ocean in the lowest part of the Earth’s mantle surrounding the Earth’s core.
How do we know these structures exist?
Scientists use seismic tomography to create a map of the Earth’s interior by measuring tremors at several locations on the surface during earthquakes. Rocks and liquids inside the Earth have different densities, so waves travel through them at different speeds. By studying this data, geologists figure out what type of material the waves travel through.
It is through this method that two large and strange structures known as Large Low Shear Velocity Regions (LLSVPs) have been discovered. In these areas, waves propagate more slowly than through the surrounding lower mantle. Below Africa, the region known as “Tuzo” is about 800 kilometers high.
So what are these mysterious blobs? One hypothesis is that the LLSVPs are piles of oceanic crust that have been subducted and accumulated over billions of years. Another theory is that these pieces are pieces of an ancient planet.
Teia is a hypothetical Mars-sized planet that collided with Earth about 4.5 billion years ago, throwing off enough rock to form the Moon. It has been suggested that the blobs are actually parts of Teia itself: the denser mantle of a protoplanet that mixed with Earth’s during the collision. In 2021, the team simulated a scenario and found that Teia’s mantle might have survived if it had been only 1.5 to 3.5 percent denser.
Although we don’t know for sure what these blobs are and will never see them directly, the research methods under our feet are constantly improving. Hopefully, it’s only a matter of time before we can call them what they are rather than mysterious giant blobs lurking deep beneath our feet.
