Question

What is the iridium anomaly?
Pick one of the below:
A type of meteorite
Unusually high concentration of iridium in a clay layer
A volcanic ash layer
A type of dinosaur fossil

Answer 1

The iridium anomaly refers to an unusually high concentration of iridium in a clay layer. This phenomenon is primarily associated with the Cretaceous-Paleogene (K-Pg) boundary, marking the extinction event that wiped out the dinosaurs and many other species around 66 million years ago, which is thought to have been caused by a massive asteroid impact.