Millions of years ago, a city-sized asteroid smashed into Labrador with so much force that it heated rocks to a whopping 2,370 C — the hottest temperature ever known for a rock on the surface of the Earth, scientists say.
The rock was found by Michael Zanetti, now a post-doctoral researcher in earth sciences at Western University in London, Ont., in 2011. At that time, he was part of a mock “mission to the moon” at 28-kilometre-wide Mistastin Lake crater left behind by the powerful asteroid impact.
Now an analysis led by Nicholas Timms at Curtin University in Perth, Australia, reports evidence that the rock was exposed to record-breaking temperatures — described as “the highest recorded from any crustal rock.” The research by Timms, Zanetti and colleagues in Australia, Switzerland and the U.S., was published in the journal Earth and Planetary Science Letters.
Mistastin Lake crater was created when a five-kilometre-wide asteroid exploded near the surface of the Earth just east of what is now the Labrador-Quebec interprovincial boundary 38 million years ago, when the early forerunners of today’s horses, deer and rodents roamed North America.
The crater is used by space scientists as a stand-in or “analog” for the far side of the moon because both those places are covered in a type of pale-coloured rock called anorthosite, said Zanetti.
In 2011, the Canadian Space Agency funded three missions to the crater to test how efficient it was to have an astronaut and robotic rover exploring together, and Zanetti, then a PhD. student at Washington University in St. Louis, Mo., took part in the third.
“I was essentially assisting the proto-astronauts in note taking,” he recalled.
The team was exploring about halfway up the wall of the crater called Discovery Hill, where you can find solidified “pools” of rock that had been melted during the impact. Most of the rocks are dull, normal-looking volcanic rocks, Zanetti said.
“So when you see something that looks a little exotic, you’re like, ‘What the heck is that?'”
A fist sized, shiny, glassy rock sitting on the ground caught Zanetti’s…