For more than a decade, Western University planetary geologist Gordon “Oz” Osinski led expeditions to Lake Camestin in Labrador. The environment is an ideal training ground, as the features and rock formations created by the powerful impact (and intense heat) of an asteroid 36 million years ago uniquely mimic the Moon’s surface.

Osinski, Neeraja Chinchalkar, a research technician at the Western Laboratory for Earth and Planetary Materials Analysis (EPMA), and their colleagues have found new evidence that another asteroid impact once produced similarly extreme (and therefore rare) high temperatures exceeding 2,370 °C ( 4172°F) at another remote impact structure in northern Quebec.

For the study, published in the journal Earth and Planetary Science Letters, Chinchalkar analyzed glass from rock samples collected by Osinski from the West Clearwater Lake impact structure in Quebec in 2014 using an electron microprobe and scanning electron microscope. The analysis revealed evidence of naturally occurring cubic zirconia, a mineral that requires temperatures of at least 2,370°C to form. To put this into perspective, the temperature of lava from volcanoes on Earth ranges from about 800°C to a maximum of about 1200°C.

“To reconstruct the meteorite impact event millions of years ago, we looked at the structures found in zircon grains. We found evidence that the target rocks reached extremely high temperatures, which, combined with high-pressure conditions, melted and transformed these terrestrial rocks. We left space in space that can be studied for years and will only contribute to our understanding of the universe.” We left unique examples that have been modified.” said Chinchalkar.

Field photographs of sampling areas. A: Sample 1 was collected from a glassy set in a breccia-containing melt; B: Close-up view of the glass dam; A: An outcrop of molten rock containing a large chunk of bedrock. The white square indicates the location (D). D: Close-up of the area marked with a square at C; sample 2 was collected from the cooled vitreous edge. The bottom left handle is for zooming. Credit: Earth and Planetary Science Letters (2024). DOI: 10.1016/j.epsl.2024.118714
While previous studies have shown that molten material from meteor impacts can reach such high temperatures, little direct evidence has been available on Earth. In fact, before this new study, such evidence had only been found in one meteorite crater: the impact structure of Lake Kamestastin.

“Kamestastin Lake contains some of the best-preserved molten rock on Earth, which is among the highest priority samples that future lunar astronauts will want to find and retrieve,” said Osinski, a professor of earth sciences. “Now that we have found evidence of these incredible effects of molten rock in West Clearwater Lake, we have a new place on Earth where astronauts, students, and geologists like me can work and learn.”

Examination of rock samples from West Clearwater Lake also found evidence of reidite, a mineral formed under extreme pressure exceeding 20 gigapascals, a measurement of the physical force applied to an object.

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

Previously, reidite had been found in only 10 meteorite impact structures on Earth, including Houghton, Nunavut, and Steen River, Alberta.