Study links dinosaur extinction to carbon-rich ‘C-type' asteroid

A new study suggests that the Chicxulub impact crater, which contributed to the extinction of the dinosaurs, was caused by a carbon-rich "C-type" asteroid.

The Chicxulub crater, located off Mexico's Yucatán Peninsula, is one of the largest impact craters on Earth, measuring 200 kilometers (120 miles) in diameter and 20 kilometers (12 miles) in depth. It is believed to have been created by an asteroid about 10 kilometers (6 miles) wide.

C-type asteroids, rich in carbon and believed to have formed in the outer regions of the early solar system, can now be found in the asteroid belt between Mars and Jupiter. These asteroids were scattered when Jupiter migrated early in the solar system's history.

Researchers from the University of Cologne, including co-author Mario Fischer-Godde, analyzed the layer of material deposited globally after the impact 66 million years ago. They focused on ruthenium, a rare metal on Earth, to identify the asteroid's composition.

Samples from Denmark, Italy, and Spain all showed the same ruthenium signature, confirming the metal's extraterrestrial origin and ruling out theories that volcanic eruptions contributed to the metal's presence.

"The ruthenium in this layer is almost entirely from the asteroid," Fischer-Godde said.

Craig Walton of the University of Cambridge, not involved in the study, found the research promising but noted that it's still uncertain whether the impactor was an asteroid or comet.

“This research provides valuable insights into the objects that have dramatically shaped Earth's history,” Walton said.