2,370 degrees Celsius: this is the temperature at which this rock was formed during the impact of a meteorite on Earth. Unless we dive into the core of our planet, we do not find this temperature on the surface of the Earth.
In 2011, geologists found, within a crater, a single stone. But it was not like the others: in a study published a few years after its discovery, it was found that the temperature conditions necessary for its formation were estimated at 2,370 degrees Celsius. It’s very, very hot.
In fact, it is quite simply the rock having reached the highest temperature on Earth, according to our knowledge. By “on Earth”, we mean on the surface: in the mantle, the first layer is around 2,000 degrees (therefore lower) and deeper down it reaches more than 3,500 degrees (much more).
Other scientists have taken new rocks from the same site as the one previously analyzed. This confirms that these minerals formed at record high temperatures of over 2,300 degrees. These are recent results published on April 17, 2022 in Earth and Planetary Science.
How do we know its formation temperature?
By the time these rocks are analyzed, they are already formed. They are therefore cold, they are only 2,300 degrees in the hands of scientists. What is precisely evaluated here is its formation temperature. These are therefore temperatures from the past: but how can we assess so precisely the environment in which a particular rock was formed? The answer is in the zircon.
By studying this rock, the scientists discovered that it contained zircons, minerals one of whose particularities is to crystallize exclusively at very high temperatures. The key to measurement is precisely this crystallization: the specific structure that the studied zircon takes reveals the precise temperature of formation, because each level of temperature leads to a different crystallization. And for an accurate measurement, it is a question of measuring several crystals, which is what the authors of this study did.
impact rock
The rock studied comes from a meteorite impact, extreme conditions favorable to the production of very high heat. During this type of impact, it is generally a “vitreous” rock, close to glass, which is formed. If the rocks studied here formed in temperatures of 2,300 degrees, the sedimentary rock around them would have reached 1,673 degrees.
Scientists have also discovered very specific minerals called reidites, which form exclusively at high temperatures and pressure. All of these discoveries provide a better understanding of the heat and pressure conditions that occur during a meteorite impact. ” We’re starting to realize that if we want to find evidence of such high temperatures, we need to look at specific regions instead of picking randomly from an entire crater. “, explain the authors.