Scientists Find Hidden Mountains 100 Times Taller Than Mount Everest — But There's One Problem

What scientists have discovered in new research goes beyond the superficial knowledge about Earth’s mantles, the semi-solid area below the crust. Two continent-sized islands that easily overshadow the height of the greatest peak in the world, Mount Everest, were found buried deep under the surface of the planet, located beneath Africa and the Pacific Ocean, as per a study published in the journal Nature. Hence, this pretty much rules out one big prior knowledge about the Earth’s mantle. It was eclipsed by conventional theories suggesting it is a rapidly flowing system, but that is outdated information now. 

Researchers from Utrecht University in the Netherlands have labeled these subterranean regions as “islands of rock” with low seismic activity. They were located 2,000 kilometers (1,200 miles) below the surface with heights reaching nearly 1,000 kilometers (620 miles) at the intersection of the planet’s core and the mantle. To put it into perspective, Mt. Everest is 8.9 kilometers (5.5 miles) tall, which means the subterranean islands are 100 times taller than the peak. These hidden islands were first mapped out in the late 20th century through seismic analysis and are said to be ancient, more than half a billion years old.

New studies have explained that the islands, now called Large Low Seismic Velocity Provinces (LLSVPs), are hotter than their surroundings and tucked in a mantle with a minimal flowing system. Head researcher and seismologist Arwen Deuss expressed the unpredictability of the islands’ existence. “Nobody knows what they are, and whether they are only a temporary phenomenon or if they have been sitting there for millions or perhaps even billions of years,” he said, per Eureka Alert. Deus is a professor of the structure and composition of Earth’s deep interior at Utrecht University. 

According to the study, seismologists analyze oscillations produced in the Earth’s mantles by large earthquakes enabling them to detect subsurface anomalies. A vast “graveyard” of tectonic plates surrounds the LLSVPs, that may have reached there through subduction. It is the geological process where a tectonic plate below another plate sinks into the deep depths near the molten core, about 3,000 kilometers, from the Earth’s surface, Deuss revealed. 

Additionally, it was found that the seismic waves slow down near the LLSVPs when earthquakes occur, hence the name. Sujania Talavera-Soza, co-author of the study and Deuss’ colleague explained how the pattern of damping of seismic waves in the region left scientists in a puzzle. “Against our expectations, we found little damping in the LLSVPs, which made the tones sound very loud there,” she said, adding that the cold slab graveyard exhibited sufficient damping. 

To accumulate detailed information about the LLSVPs, the researchers further investigated the minuscule materials that made up the hot islands of rock. Grain sizes play a pivotal role, suggested study co-author Laura Cobden. The LLSVPs are composed of larger grains in contrast to the smaller grains of the cold slab graveyard tectonic plates, per the study. The difference in grain sizes accounts for the energy loss in seismic waves, thus, allowing them to pass with minimal damping in LLSVPs. The large size of the LLSVP grains indicates that the islands are much older than the cold slabs near them. 

Most theories about the Earth’s mantle have predominantly explained that it consists of recycling material as part of its convection processes. However, the fact that LLSVPs have resisted change in form and composition confirms their ancient existence.