Tracking down the asteroid that sealed the fate of the dinosaurs | Science & Technology

According to a widely accepted theory, the mass extinction at the Cretaceous-Paleogene boundary was triggered by the impact of an asteroid at least 10 kilometres in diameter near Chicxulub on the Yucatán Peninsula in Mexico. On impact, the asteroid and large quantities of earth rock vaporized. Fine dust particles spread into the stratosphere and obscured the sun. This led to dramatic changes in the living conditions on the planet and brought photosynthetic activity to a halt for several years.

The dust particles released by the impact formed a layer of sediment around the entire globe. This is why the Cretaceous-Paleogene boundary can be identified and sampled in many places on Earth. It contains high concentrations of platinum-group metals, which come from the asteroid and are otherwise extremely rare in the rock that forms the Earth’s crust.

By analysing the isotopic composition of the platinum metal ruthenium in the cleanroom laboratory of the University of Cologne’s Institute of Geology and Mineralogy, the scientists discovered that the asteroid originally came from the outer solar system. “The asteroid’s composition is consistent with that of carbonaceous asteroids that formed outside of Jupiter’s orbit during the formation of the solar system,” said Dr Mario Fischer-Gödde, first author of the study.

The ruthenium isotope compositions were also…