Ancient Ocean Floor Discovered Around Earth’s Core

A new study published in Science Advances reveals that there’s an ancient sunken ocean floor in between the layer of the Earth’s mantle and its core. Scientists from the University of Alabama discovered this through global-scale seismic imaging that was collected over years, indicating ultra-low velocity zones (ULVs) or places with strong wave speed reduction, along the core-mantle boundary (CMB). “Analyzing 1000s of seismic recordings from Antarctica, our high-definition imaging method found thin anomalous zones of material at the CMB everywhere we probed,” says Dr Edward Garnero who co-led the study. “The material’s thickness varies from a few kilometers to 10s of kilometers. This suggests we are seeing mountains on the core, in some places up to five times taller than Mt. Everest.” Researchers believe these mountains to be former oceanic sea-floors that sank to the CMB. The presence of “mountains” sheds light on how heat escapes the Earth’s core, as material from the ancient ocean floors could have become swept back up to the surface through hot spots and volcanic eruptions. Learn more at

Image courtesy of Argonne National Laboratory/Flickr