(ORDO NEWS) — Chinese scientists have built a geological model of the early Earth.
According to modern scientific data, the Earth was formed 4.54 billion years ago. Despite this, it is not possible to detect rocks older than 3.8 billion years, only isolated isolated zircon crystals are found.
It is these ancient inclusions that serve as the main source of information about the Earth millions of years after its formation.
Scientists from the China University of Geosciences in Wuhan created a computer model based on data from previous studies and tried to find out where the first protocontinents went and why no rocks remained from them.
It is known that the earliest of them appeared about 4.2 billion years ago. It turned out that the flow of internal heat of the Earth in the pre-Archaean era was three to four times higher than the modern one.
The molten upper mantle periodically emerged through weakened zones to the surface in the form of magma.
At the same time, unstable early continents broke apart, partially melted, and plunged back into the mantle.
Gradually, “roots”, or “keels”, of future cratons formed under the protocontinents, consisting of partially melted blocks of the earth’s crust, immersed in a cooled and dehydrated mantle.
Cratons are an ancient part of modern continents, composed of a typical continental crust with a thickness of 35-45 kilometers.
They are deeply immersed in the mantle and are very complex in comparison with the ordinary lithosphere.
According to Chinese scientists, it took about a billion years before these “roots” hardened, and normal continental crust formed above them.
Summing up, we can say that the ancient earth’s crust and protocontinents plunged into the mantle and were processed in it into granite massifs – the foundation of modern continents.
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