Unexplained structures discovered underneath ocean completely baffle scientists with 'lost world' theory

Scientists have been left stumped following a new discovery deep below the Pacific Ocean.

There's still much to learn about our planet and what's below the Earth's surface; something which researchers at Zurich-based university, ETH Zurich, have recently proven.

Geophysicists at ETH Zurich have been looking into the Earth's lower mantle in particular.

The aim was to 'find out where plate material that has sunken into the Earth's interior is located' by using a high-resolution model, a press release explained - but they ended up stumbling across something unexpected.

While scientists thought they already had a generally sound understanding of Earth's tectonic plates, it's been revealed that earthquake waves behave differently than previously assumed.

They were expecting to find submerged tectonic plates throughout the Earth's mantle in what's known as subduction zones (where two plates meet and one subducts beneath the other into the Earth's interior).

However, new research - published in the journal Scientific Reports - has found such plates in places they shouldn't have been.

One place they've been found is under the Pacific Ocean. There's now theories that there could be a 'lost world' beneath the world's largest and deepest ocean.

Unexpected material has been located below the Pacific Ocean (Sebastian Noe / ETH Zurich)

Discussing the momentous find, Thomas Schouten, first author and doctoral student at the Geological Institute of ETH Zurich, said: "Apparently, such zones in the Earth's mantle are much more widespread than previously thought."

Current plate tectonic theories suggested that there shouldn't be any subducted plates below the Pacific as it was allegedly 'impossible that there were subduction zones nearby in the recent geological history'.

Further discussing the 'dilemma' they now face, Schouten went on: "With the new high-resolution model, we can see such anomalies everywhere in the Earth's mantle. But we don't know exactly what they are or what material is creating the patterns we have uncovered."

The findings have left scientists questioning everything they knew about Earth's structure (Getty Stock Image)

As humans cannot physically visit the area in question to conduct further investigations, experts can only speculate about what exactly the discovered material is and why it's there.

"We think that the anomalies in the lower mantle have a variety of origins," Schouten said of their ongoing theories.

"It could be either ancient, silica-rich material that has been there since the formation of the mantle about 4 billion years ago and has survived despite the convective movements in the mantle, or zones where iron-rich rocks accumulate as a consequence of these mantle movements over billions of years."

In a bid to find out more about the mystery matter, more research with even better models will be needed.

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