TECHNONIC LAND PLASS
Surprisingly, a new study revealed that there is a “wrong argument” in the debate on the formation of the plates tectonics. After all, the first land crust was surprisingly similar to the current one.
A study at the beginning of the month in the Nature He revealed that the current earth’s crust has a surprisingly similar composition to the first outer layer of the planet, or “protocrasta.”
This primitive rock enclosure had chemical signatures that were thought to occur only in continental crusts created by the subduction process, in which a tectonic plate slides under another.
Only, after all, not. The new study comes to theorize that tectonic plates is not really necessary to produce these signatures.
As you refer to, these findings come to warm (and confuse) the debate about when the plaque tectonics began on our planet.
No one knows exactly when or because the surface of the earth has divided into plates that shock each other, forming mountains and volcanoes and causing earthquakes.
Historically, the fact that chemical signatures observed in the modern tectonic plates processes occur in protocroste has been used as proof To support the theory that the tectonics of signs began almost as soon as the earth had solid soil – about 4 billion years ago.
“Now we know that this is probably a wrong argument”told Live Science the main author of the study, Craig O’NeillGeophysicist at Queensland University of Technology, Australia.
“Yes, this signature is today [através da tectónica de placas]. However, the assumption that the earth has always behaved like now, over time, is obviously worrying, ”added the scientist.
Farlicable “Signatures”
The exact signatures in debate, in this study, are garment elementslike the titanium and the niobiumwhich combine in the crystal structure of rocks as they solidify from the hot magma.
What the new study realized was that the chemistry of the molten primitive land was quite different from the current one. As the earth solidified from the cast rock, the iron-rich portions of this magma sink and concentrated, becoming the current metallic nucleus.
This means that the Manto has become less iron rich over time.
I.e, The magma of the cloak found in modern subduction zoneslike the “fire ring” of the Pacific, can act differently to the magma found in the primitive land.
Craig O’Neill explained that the standard they found in the investigation resembled “notably the signing of the subduction zone”, which means that chemical signatures cannot be used as proof that the subduction was occurring in the primitive land.
These signatures can also result directly from the transition initial of a planet with a liquid surface for one with one solid surface.
“After all, some of the evidence that people have used to argue in favor of primitive plates tectonics probably show nothing from the plates tectonics,” O’Neill concluded.
“Probably are showing us an older crust“He added.
The study concluded that the most likely is that the whole planet has passed to the tectonic plate system later, between 3.2 billion and 2.7 billion of years ago.
