Meteor impact on Lake Quebec produces rare rocks and evidence of extreme heat

For more than a decade, planetary geologist Gordon “Oz” Osinski of Western University has led expeditions to Lake Kamestastin in Labrador. The environment is a perfect training ground because the features and rock formations – created by the violent impact (and extreme heat) of an asteroid 36 million years ago – uniquely mimic the surface of the moon.

Osinski, Neeraja Chinchalkar, the research technician at the Western Earth and Planetary Materials Analysis (EPMA) Laboratory, and their collaborators have now discovered new evidence that another meteorite impact once produced equally extreme (and respectively rare) high temperatures, exceeding 2,370 °C (4,172). °F), at another remote impact feature in northern Quebec.

For the study, published by the journal Earth and planetary science letters, Chinchalkar analyzed glass from rock samples originally collected by Osinski in 2014 at the West Clearwater Lake impact structure in Quebec using an electron microprobe and a scanning electron microscope. The analysis showed that it is natural zirconia, a mineral that requires a temperature of at least 2,370 °C to form. To put this into perspective, lava flows from volcanoes on Earth range from about 800°C to a high of about 1,200°C.

“We looked at the structures present in zircon grains to reconstruct a meteorite impact from millions of years ago. We found evidence that the target rocks reached extremely high temperatures, which, combined with high-pressure conditions, caused these Earth rocks to melt and transform. ” have left behind unique space-modified samples that can be studied for years to come and will only further our understanding of the cosmos,” said Chinchalkar.

While previous research has suggested that material melted by meteor collisions can reach such extreme temperatures, direct evidence on Earth is scarce. In fact, until this new study, such evidence was only found in one meteorite crater: the Kamestastin Lake impact structure.

“Kamestastin Lake contains some of the best preserved melt rocks on Earth, which are among the highest priority samples that future astronauts to the moon will want to find and sample,” said Osinski, professor of earth sciences. “Now that we have found evidence of this incredible impact of rock melt at West Clearwater Lake, we have a new destination on Earth for astronauts, students and geologists like me to train and study.”

The examination of rock samples in West Clearwater Lake also revealed evidence of reidite, a mineral that forms under extreme pressure of more than 20 gigapascals, a measurement of the physical force exerted on an object.

“This discovery highlights the variable and dynamic conditions that occur during the process of melt generation caused by meteorite impacts on Earth and beyond,” Chinchalkar said.

Reidite has previously only been found at 10 meteorite impact structures on Earth, including Haughton, Nunavut and Steen River, Alberta.