Researchers say they have identified the likely type of meteorite that struck Earth 66 million years ago and helped trigger the extinction of about 75% of all species, including every non-avian dinosaur. According to ScienceDaily, the impactor was probably a rare CO chondrite, also known as a carbonaceous chondrite of the Ornans class.
The conclusion came from nickel isotope analysis of material left behind by the Cretaceous-Paleogene impact. The study involved researchers from the University of British Columbia, Paris, Brussels and Vienna, and was published in Science Advances.
Dr. Philippe Claeys, who worked on the project as a visiting professor at UBC, said CO chondrites are unlike the typical meteorites seen in museum collections. He noted that they contain relatively low amounts of volatile elements such as carbon, zinc, water and sulfur.
That composition may matter because it suggests sulfur from the meteorite itself may not have been the main cause of the disaster. Instead, the researchers say the huge amount of fine debris blasted into the atmosphere may have played the larger role in the extinction event.
The impactor is estimated to have been 10 to 15 kilometers wide and traveling about 64,000 km/h when it created the Chicxulub crater beneath Mexico's Yucatán Peninsula. Scientists say the meteorite likely came from either the outer Solar System or the outer part of the asteroid belt near Jupiter.
