abstract:The term iridium anomaly commonly refers to an unusual abundance of the chemical element iridium in a layer of rock strata, often taken as evidence of an extraterrestrial impact event because of the case of such an anomaly at the Cretaceous–Paleogene boundary (often abbreviated either K-Pg boundary or K–T boundary).
Dr Norman MacLeod, the keeper of palaeontology at the Natural History Museum, London, UK, told the BBC that the iridiumanomaly could be attributed to other factors.