The pest that supports the evidence for an asteroid collision causing the extinction of dinosaurs is the presence of a specific mineral called iridium, which is found in high concentrations in the clay layer marking the boundary between the Cretaceous and Paleogene periods (known as the K-Pg boundary). Iridium is relatively rare in Earth's crust but is more abundant in extraterrestrial objects such as asteroids and comets. The high levels of iridium found in the K-Pg boundary clay layer indicate that a massive asteroid collision occurred and deposited the extraterrestrial material across the Earth, suggesting a link between the asteroid impact and the extinction event that wiped out the dinosaurs.
