Ancient origins of mysterious masses of rock found

Scientists pieced together the ancient origins of mysterious masses of rock found deep underground.

Ancient origins of mysterious masses of rock foundUnderground continents deep in Earth’s belly may have formed when an ancient ocean of magma solidified on the surface of the baby planet 4.5 billion years ago, according to a new study. 

The finding was detailed in a fascinating story on the American Geophysical Union blog GeoSpace

As reporter Abigail Eisenstadt explains, scientists have known about these mysterious masses buried blobs of hot, compressed rock since the 1970s.

Earthquakes reverberate through the rest of the mantle at a steady pace, but hit serious speed bumps when they rumble through these massive hunks of stone.

These peculiar patterns of seismic activity helped scientists spot the continents on the border of Earth’s mantle and molten outer core, but they still don’t know when or how the structures emerged. Some scientists theorize that bits of the planet’s crust dipped down into the mantle, broke off and clumped together over time, Geospace reported.

Now, new analyses of volcanic rock paint a different picture: The underground continents may be as old as Earth itself, and likely survived the planet-rocking impact that first formed the Moon, the study authors reported July 31 in the journal Geochemistry, Geophysics, Geosystems

It’s amazing that these regions have survived most of Earth’s volcanic history relatively untouched, study co-author Curtis Williams, a geologist at the University of California, Davis, told GeoSpace.