Remnant of world's largest 'lava lamp blob' found off New Zealand coast

[Judi Lynn]

By Brandon Specktor - Senior Writer 2 days ago

New Zealand's Hikurangi Plateau was once part of a gargantuan volcanic mountain that covered 1% of Earth's surface.



The undersea Hikurangi Plateau (outlined) has a greater area than the entire New Zealand mainland.
(Image: © Victoria University of Wellington)

About 120 million years ago, a gargantuan blob of hot rock detached from the edge of Earth's core and oozed up toward the planet's surface. Today, a huge chunk of that blob — or "superplume," as geologists call it — may be lurking off the coast of New Zealand, new research suggests.

In a study published May 27 in the journal Science Advances, researchers measured the speed of seismic waves traveling through a layer of Earth called the mantle that sits between the planet's crust and outer core. They focused on Hikurangi Plateau — a vast, triangle-shaped chunk of volcanic rock located about 2,000 miles (3,200 kilometers) beneath the top of the South Pacific Ocean, just off the coast of New Zealand's North Island. The team found a match between the seismic waves traveling through that chunk and those traveling through two other nearby volcanic structures.

According to the study authors, it's likely that all three of these underwater structures were once part of the same gargantuan mega-plateau, formed more than 100 million years ago during the largest outpouring of volcanic material in Earth's history.

"The associated volcanic activity may have played an important role in Earth history, influencing the planet's climate and also the evolution of life by triggering mass extinctions," study co-author Simon Lamb, an associate professor at Victoria University of Wellington in New Zealand, said in a statement. "It is an intriguing thought that New Zealand now sits on top of what was once such a powerful force in the Earth."

More:
https://www.livescience.com/new-zealand-mantle-superplume-blob.html