"Back in the 1980s, scientists made a remarkable discovery. Two gigantic, continent-sized blobs were embedded deep in the Earth. One is under Africa, and one is under the Pacific Ocean. They’re called LLSVPs, or Large Low-Shear-Velocity Provinces, and they have unusually high iron levels. The iron concentration changes the speed of seismic waves that travel through them, leading to their discovery."
Add comment