Scientists believe they have found a window to the dawn of time on Earth, hidden beneath the Pacific Ocean.
The 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 deep on the seabed off the coast of New Zealand.
So what do these two locations on opposite sides of the world have in common?
Together, they shed light on the world in its infancy, offering unexpected clues about the origins of the planet we know today—and perhaps life itself.
Writing for Conversationthe researchers explained that their work began after de Ronde created a new detailed geological map of an area known as the Barberton Greenstone Belt, which lies in the South African highveld region.
“Despite many attempts, the geological formations in this area have proven difficult to decipher,” the pair write.
He argues that the bedrock of the Belt contradicts our widely accepted understanding of plate tectonics at the time.
But they say their new research has offered “the key to cracking this code.”
Part of South Africa’s Barberton Greenstone Belt(International Geoheritage Commission)
De Ronde’s map revealed a fragment of an ancient deep sea floor in the Barberton Greenstone Belt, formed about 3.3 billion years ago, when the world was only 1.2 billion years old.
“However, there was something very strange about this seabed,” write Lamb and de Ronde.
“And it took our study of rocks laid down in New Zealand, at the other end of Earth’s long history, to make sense of it.”
The two experts say that the common understanding of the early Earth as a fiery ball of molten magma whose surface was too weak to form rigid plates—and suffered from earthquakes as a result—is incorrect.
Rather, they hypothesize that the young planet was constantly rocked by large earthquakes that were triggered each time one tectonic plate slipped beneath another in a subduction zone.
Looking at de Ronde’s map of the Barberton Greenstone Belt, they realized that its “messy” rock layers were reminiscent of more recent submarine landslides that had 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 a mixture of sedimentary rocks.
Hikurangi Subduction Zone Projectwww.youtube.com
These rocks were originally deposited on the sea floor off the coast of New Zealand about 20 million years ago, on the edges of a deep ocean trench that was the site of frequent large earthquakes.
By considering the formation of this New Zealand bedrock, experts say they have solved the mystery behind the formations of the Barberton Greenstone Belt.
Like its young successor, these structures were “the remnant of a gigantic landslide containing sediments deposited both on land and in very shallow water, mixed with those that had accumulated on the deep sea floor,” they concluded.
Simply put, if the rock layers in New Zealand were formed by earthquakes, then so were the layers in the Barberton Greenstone Belt – undermining the theory that the early Earth was not equipped for such shocks.
Additionally, Lamb and de Ronde suggest that their work “may also have unlocked other mysteries,” as they point out, “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, which was struck by more than 200,000 lightning strikes over the next 11 hours.
“In the same volcanic area, underwater volcanoes erupt an extremely rare type of lava called boninite. This is the closest modern example of lava that was common on the early Earth,” they add.
Lightning-pierced ash clouds spew from violent volcanic eruption in 2022(Tonga Geological Services via NOAA)
Lamb and de Ronde argue that the large amount of volcanic ash found in the Barberton Greenstone Belt “may be an ancient record of similar volcanic violence”.
More interestingly, they suggest that the associated lightning strikes could have potentially “created the crucible for life where the basic organic molecules were formed.”
In other words, subduction zones aren’t just a source of tectonic chaos, they may have been the spark that ignited the flame of life itself.
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