Strange structures discovered in the Pacific could change our understanding of Earth

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Scientists believe they have found a window into the dawn of time in Landand is hidden under the Pacific Ocean.

A team led by geophysicist Simon Lamb of the University of Wellington and scientist Cornel de Ronde of GNS Science said the key to our past lies in a remote corner of South Africa and far down on the seabed off the coast of New Zealand.

So what do these two sites, on opposite sides of the world, have in common?

Together, they shed light on the world in its infancy and offer unexpected clues about the origins of the planet we know today (and possibly). life itself.

writing for The conversationThe scientists explained that their work began after De Ronde created a new, detailed geological map of an area known as the Barberton Greenstone Belt, which is located in the high country of South Africa.

“The geological formations of this region have proven difficult to decipher, despite many attempts,” the two write.

They claim that the Belt’s bedrock is inconsistent with our widely accepted understanding of plate tectonics at the time.

But they say their new research has offered “the key to cracking this code.”

A section of the Barberton greenstone belt in South Africa(International Commission on Geoheritage)

De Ronde’s map revealed a fragment of the ancient deep sea floor in the Barberton Greenstone Belt, created about 3.3 billion years ago, when the world was just 1.2 billion years old.

“However, there was something very strange about this seabed,” Lamb and de Ronde write.

“And it has taken our study of rocks deposited in New Zealand, at the other end of Earth’s long history, to make sense of it.”

The two experts argue that the general understanding of the early Earth as a fiery ball of molten magma, whose surface was too weak to form rigid plates and, by extension, suffer earthquakes, is flawed.

Rather, they postulate, the young planet was continually shaken by large earthquakes that were triggered whenever one tectonic plate slid beneath another in a subduction zone.

Looking at de Ronde’s map of the Barberton greenstone belt, they realized that its “scrambled” rock layers were reminiscent of more recent underwater landslides that occurred in New Zealand.

These landslides were triggered by large earthquakes along the country’s largest fault, the megathrust in the Hikurangi subduction zone, where the bedrock is made up of a hodgepodge of sedimentary rocks.

The Hikurangi Subduction Zone

These rocks were originally deposited on the seafloor off the coast of New Zealand about 20 million years ago, at the edges of a deep ocean trench, which was the site of frequent large earthquakes.

By examining the formation of this New Zealand bedrock, experts claim to have solved the mystery behind the Barberton Greenstone Belt formations.

Like their young successor, these structures were “the remains of a gigantic landslide containing sediments deposited both on land and in very shallow waters, mixed with those that accumulated on the deep sea floor,” they concluded.

Simply put, if the rock layers in New Zealand were formed by earthquakes, so were those in the Barberton Greenstone Belt, subverting the theory that the early Earth was not equipped to endure such tremors.

Furthermore, Lamb and de Ronde suggest that their work “may have revealed other mysteries as well,” because, they note, “Subduction zones are also associated with explosive volcanic eruptions.”

They cite the example of Tonga’s Hunga Tonga-Hunga Ha’apai volcano, which erupted in January 2022 with the energy of a “60-megaton atomic bomb” and sent a huge ash cloud into space, through which Over the next 11 hours, more than 200,000 lightning strikes.

“In the same volcanic region, underwater volcanoes are erupting an extremely rare type of lava called boninite. “This is the closest modern example of a lava that was common on the early Earth,” they add.

Lightning-pierced ash clouds spewed from violent 2022 volcanic eruption(Tonga Geological Survey via NOAA)

Lamb and de Ronde argue that the large amounts of volcanic ash found in the Barberton greenstone belt “may be an ancient record of similar volcanic violence.”

And, even more interesting, they suggest that the associated rays could have “created the crucible for life where the basic organic molecules were forged.”

In other words, subduction zones are not only the source of tectonic chaos, but they could also have been the spark that ignited the flame of life itself.

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