It is believed that a continent of massive dimensions once existed in the past. However, the said continent sank in the past and scientists are trying to find out more about it.
A study recently published in the journal Nature Geoscience study reveals a number of findings that are revolutionizing what was known about the behavior of tectonic plates.
The research, conducted by scientists at the University Of Chicago (USA) was to examine in detail the collision of Eurasian with Indian tectonic plates, which started some 60 million years ago and is still in slow motion, and is even responsible for many phenomena, and the appearance of the Himalayas.
Experts utilized numerous data sources in order to figure out the original site of the two continental places before they started ‘crashing’ into each other.
“What we found is that half of the mass that was there 60 million years ago is missing from the earth’s surface today, “said Miquela Ingalls, a graduate student in geophysical sciences who led the project as part of her doctoral work.
It was a totally unexpected findings researchers concluded.
After considering nearly all other possibilities the land mass might be accounted for, experts concluded that such a humongous mass discrepancy could only be scientifically explained if the ‘missing chunk’ had gone back into the Earth’s Mantle, something experts considered as IMPOSSIBLE on such scale.
This new theory could clarify some phenomena that baffled scientists in the distant past, as the presence of lead and uranium in volcanic lava.
These elements are present in the earth’s crust but are very rare in the mantle; the possibility that the earth surface is absorbed by the interior of the planet explains why these may be present in the magma.
“We’re taught in Geology 101 that continental crust is buoyant and can’t descend into the mantle,” Ingalls said. The new results throw that idea out the window.
“We really have significant amounts of crust that have disappeared from the crustal reservoir, and the only place that it can go is into the mantle,” said David Rowley, a professor in geophysical sciences who is one of Ingalls’ advisors and a collaborator on the project.
“It used to be thought that the mantle and the crust interacted only in a relatively minor way. This work suggests that, at least in certain circumstances, that’s not true.”
“The implication of our work is that, if we’re seeing the India-Asia collision system as an ongoing process over Earth’s history, there has been a continuous mixing of the continental crustal elements back into the mantle,” said Rowley. “And they can then be re-extracted and seen in some of those volcanic materials that come out of the mantle today.”