A meteorite fell in Canada about 36 million years ago. From the impact, what has been confirmed as the hottest rock in the history of our planet was created . The temperatures at which this rock was forged in the Mistastin crater reached 2370 ºC.
The rock was discovered in 2011 , when researcher Michael Zanetti from the University of Western Ontario (Canada) discovered a glass rock containing small grains of zircon. In 2017 they reported this finding for the first time in the journal Earth and Planetary Science Letters. It was the result of an asteroid impact.
Now, a new study using samples collected between 2009 and 2011 has confirmed the record-breaking heat of the stone that was formed during a meteorite impact that also created the 28-kilometre-wide crater of Lake Mistastin approximately 36 years ago. millions of years. The results of the new study have been republished in Earth and Planetary Science Letters.
a fiery crater
In the current investigation, the experts analyzed four more zircons in samples from the crater that came from different types of rocks in different places, which offered a more complete picture of how the impact heated the ground.
One was from a glassy rock formed on impact, two others were from rocks that melted and resolidified, and one was from a sedimentary rock containing glass shards formed on impact.
The results showed that the glass zircons formed with heat of at least 2,370 °C, as suggested by the 2017 research, and that the glass-bearing sedimentary rock had been heated to 1,673 °C.
“We’re starting to realize that if we want to find evidence of such high temperatures, we need to look at specific regions rather than randomly selecting an entire crater,” said Gavin Tolometti, lead researcher.
Circonitas y reiditas
As a curiosity, Lake Mistastin, specifically its crater, shows a great similarity with the craters of the Moon, therefore, it is often used as a substitute for space research. In fact, the initially discovered rocks were found while conducting a study on coordination and astronauts and rovers working together.
Uncovered zirconia rock is an incredibly durable mineral that condenses at high temperatures. Additionally, researchers have found a mineral called reidite that forms when zircon is subjected to extreme pressure. The impact of the asteroid was estimated between 30 and 40 gigapascals (equivalent to 300,000 to 400,000 bars).
“Based on the size of the reidite in our samples, we knew that the minimum pressure it was likely to record was about 30 gigapascals. But since there are still a lot of reidites present in some of these grains, we know that it could even be above 40 gigapascals ,” continues Tolometti.
Taking these results into account, the researchers believe that they could be used to study different craters brought from other planets, especially the Moon.
“It may be a step forward in trying to understand how rocks have been modified by impact craters throughout the solar system.”
Referencia: G.D. Tolometti et al. 2022. Hot rocks: Constraining the thermal conditions of the Mistastin Lake impact melt deposits using zircon grain microstructures. Earth and Planetary Science Letters 584: 117523; doi: 10.1016/j.epsl.2022.117523
