Earth's Core Covered By Ancient Ocean

The Earth's interior harbors many secrets, but they can't hide from dogged geologists forever.
In a new study published in the journal Science, researchers who analyzed extensive seismic imaging data from Antarctica have discovered what they believe is material from the ancient floor of an ocean, subsumed by the Earth's interior over untold millions of years to reach where it now resides near the planetary core. The giveaway? A "thin" and noticeably dense layer wedged in the the core-mantle boundary, some 2,000 miles beneath the surface.
"Analyzing thousands of seismic recordings from Antarctica, our high-definition imaging method found thin anomalous zones of material at the CMB everywhere we probed," said study co-author Edward Garnero, a professor in the School of Earth and Space Exploration at Arizona State University, in a press release.
The Earth's Core Is Wrapped in the Floor of an Ancient Ocean, Scientists Say