Researchers from the University of Texas at Austin say they believe they have definitively closed the case of what killed off the dinosaurs. The team definitively linked the extinction of the dinosaurs to an asteroid that impacted the earth 66 million years ago. The link came when the team found a key piece of evidence in the form of asteroid dust inside the Chicxulub Crater in the Yucatán Peninsula in Mexico.
Researchers say the extinction of all non-avian dinosaurs was directly related to the asteroid impact rather than a series of volcanic eruptions or other global calamity. An asteroid causing the extinction of dinosaurs has been the leading hypothesis since the 80s. The theory of what killed off most species on earth rose when asteroid dust was found in the geological layer marking the extinction of the dinosaurs.
Scientist Steven Goderis says the circle is now finally complete. Researchers on the project found asteroid dust with a matching chemical fingerprint within the crater in Mexico at the precise geological location that marks the time of extinction. The study is the latest to use data obtained in 2016 from a UT Austin mission that collected nearly 3000 feet of rock core from the crater, which is buried under the ocean today.
Data collected in that research mission has filled in gaps about the asteroid impact, aftermath, and recovery of life. Researchers note that the big signal of asteroid dust is the element iridium, which is rare in the Earth’s crust. The element is present with elevated levels in certain types of asteroids. In the study, the researchers found a spike of iridium in a section of rock pulled from the crater.
In the samples gathered by the scientists, the sediment layer deposited in the days and years after the asteroid impact is so thick scientists can precisely date the dust to two decades after the initial impact. The team says that research “puts to bed” doubts that the iridium anomaly in the geological layer isn’t related to the impact crater in Mexico. The impact triggered the extinction of 75 percent of life on Earth after creating dust that circulated in the planet’s atmosphere for no more than a couple of decades.