In a paper set to be published Monday in the Proceedings of the Academy of Natural Sciences, paleontologists at the University of Kansas say they found a “mother lode of exquisitely preserved animal and fish fossils” at the Tanis site in North Dakota’s Hell Creek Formation.
Robert DePalma, the report’s lead author, told The Guardian that the surge left “a tangled mass of freshwater fish, terrestrial vertebrates, trees, branches, logs, marine ammonites and other marine creatures,”. These creatures died minutes after a huge asteroid hit Earth.
Analysis showed that some of the fish fossils inhaled “ejecta” associated with the Chicxulub event.
What makes the find particularly momentous is the excellent state in which the fossils were unearthed. “The sedimentation happened so quickly everything is preserved in three dimensions – they’re not crushed,” said co-author David Burnham.
The fossil, found in Tanis, include what is believed to be several newly identified fish species, and others that were “the best examples of their kind”, said DePalma.
“And this particular event is tied directly to all of us – to every mammal on Earth, in fact. Because this is essentially where we inherited the planet. Nothing was the same after that impact. It became a planet of mammals rather than a planet of dinosaurs.”
In what was the most cataclysmic event in Earth’s history, the asteroid impact created the Chicxulub crater, eradicating 75 per cent of the planet’s animal and plant species, wiping out the dinosaurs and paving the way for the rise of humans.