A rare type of meteorite known as a CO chondrite was likely the object that slammed into Earth 66 million years ago and triggered the extinction of about 75 percent of all species, including every non-avian dinosaur.

Researchers from the University of British Columbia (UBC), Paris, Brussels, and Vienna analyzed nickel isotopes preserved in material left behind by the Cretaceous-Paleogene impact to narrow down the meteorite's origin.

The study, published in Science Advances, suggests that the asteroid's unusual chemistry indicates planet-cooling dust and debris, rather than sulfur inside the asteroid, may have caused the mass extinction.

CO chondrites contain significantly less volatile elements like carbon, zinc, water, and sulfur compared to other meteorites, making it less likely that sulfur was the primary factor in the catastrophe.Instead, the vast amount of fine debris ejected into the atmosphere is believed to have played a dominant role.

The research highlights how analyzing isotopic signatures can help scientists understand the impact's mechanisms and its effects on Earth's ecosystems.