Antarctic fossils show creatures wiped out by asteroid
A study of more than 6,000 marine fossils from the Antarctic shows that the mass extinction event that killed the dinosaurs 66 million years ago was sudden and just as deadly to life in the Polar Regions.
Previously, scientists had thought that creatures living in the southernmost regions of the planet would have been in a less perilous position during the mass extinction event than those elsewhere on Earth.
The research, published today in the journal Nature Communications, involved a six-year process of identifying more than 6,000 marine fossils ranging in age from 69- to 65-million-years-old that were excavated by scientists from the University of Leeds and British Antarctic Survey on Seymour Island in the Antarctic Peninsula.
This is one of the largest collections of marine fossils of this age anywhere in the world. It includes a wide range of species, from small snails and clams that lived on the sea floor, to large and unusual creatures that swam in the surface waters of the ocean. These include the ammonite Diplomoceras, a distant relative of modern squid and octopus, with a paperclip-shaped shell that could grow as large as 2 metres, and giant marine reptiles such as Mosasaurus, as featured in the film Jurassic World.
With the marine fossils grouped by age, the collection shows a dramatic 65-70% reduction in the number of species living in the Antarctic 66 million years ago – coinciding exactly with the time when the dinosaurs and many other groups of organisms worldwide became extinct at the end of the Cretaceous Period.
Lead author James Witts, a PhD student at Leeds University’s School of Earth and Environment, said:
“Our research essentially shows that one day everything was fine – the Antarctic had a thriving and diverse marine community – and the next, it wasn’t. Clearly, a very sudden and catastrophic event had occurred on Earth. This is the strongest evidence from fossils that the main driver of this extinction event was the after-effects of a huge asteroid impact, rather than a slower decline caused by natural changes to the climate or by severe volcanism stressing global environments.”
The study is the first to suggest that the mass extinction event was just as rapid and severe in the Polar Regions as elsewhere in the world.
Continue reading at British Antarctic Survey.
Painted reconstruction of typical Cretaceous marine environment in Antarctica, including the paperclip-shaped ‘heteromorph’ ammonite by James McKay.