(ORDO NEWS) — The researchers showed that the temperature of the formation of grains of the silicate mineral zircon, found in the Mistastin impact crater, reached a record 2370 degrees Celsius for the Earth‘s surface.
Such conditions arose after the fall of a meteorite, and the data obtained will allow us to study other craters – not only on the surface of our planet, but also on the Moon.
The temperature of the Earth’s core can supposedly reach 6000 degrees Celsius, but the surface of our planet has never warmed up so much.
Even the temperature of volcanic lava rarely exceeds 1200 degrees Celsius. However, the composition of the rocks found in the impact crankcases indicates that the asteroid impact heated the rocks to more than 2,000 degrees.
One of these craters – Mistastin – is located in the Canadian province of Labrador, it was created by an asteroid that collided with the Earth about 36.4 million years ago.
In 2011, scientists found a rock there that contained small grains of the silicate mineral zircon: presumably, it could have formed at a record temperature for the Earth’s surface.
A new study by scientists from the University of Western Ontario (UK) confirmed the conjecture: the temperature of formation of zircon grains could exceed 2370 degrees Celsius.
The researchers found several more zircon grains near the bottom of the crater, formed from molten rocks after a meteorite impact.
The work, published in Earth and Planetary Science Letters, sets a new temperature record for an impact melt and provides new data to model the formation of other craters.
At the same site, scientists found reidite, an extremely rare mineral that forms when zircon is exposed to high pressure and temperature. The team found three fragments of reidite that were preserved inside the zircon grains.
This discovery made it possible to more accurately determine the pressure that arose in the crater after the fall of the meteorite. According to calculations, it exceeded 30 gigapascals, although theoretically it could reach 40 gigapascals.
These data give an idea of the pressure near the melting zone. In the melting zone itself, the pressure can probably exceed 100 gigapascals, but the rocks in it melt and evaporate, which makes it impossible to study them directly.
The scientists now plan to explore other known impact craters on Earth, such as Lac Viyashakimi in Quebec, Canada, and expand the study using samples brought back from the Moon by the Apollo mission.
There is evidence that they were also formed during the collision of the Moon with a meteorite, so the results of this study will help to better understand the processes of formation of the Earth’s satellite craters.
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