A fresh examination of seafloor crust data reveals that the seismic waves triggered by the infamous Chicxulub meteorite led to a global surge of marine volcanic activity which played a far greater role in the late Cretaceous die-offs than previously thought.
Up to now the mass extinctions have been mainly blamed on the meteorite and its aftermath, as well as on intense volcanic activity in an area of modern day India, the Deccan Traps.
But the new study indicates the shockwaves gave rise to activity across the planet of the type which caused catastrophic disturbances to the Earth’s atmosphere.
"Our work suggests a connection between these exceedingly rare and catastrophic events, distributed over the entire planet," said Professor Leif Karlstrom, from the University of Oregon, who led the research.
"The meteorite’s impact may have influenced volcanic eruptions that were already going on, making for a one-two punch."
Researchers divided the seafloor geological data into one-million-year old groupings, constructing a record back to 100 million years ago.
At about 66 million years, they found evidence for a "short-lived pulse of marine magmatism" along ancient ocean ridges.
This pulse was suggested by a spike in the rate of the occurrence of free-air gravity anomalies seen in the dataset.
"We found evidence for a previously unknown period of globally heighted volcanic activity during the mass-extinction event," said Joseph Byrnes, a doctoral student who led the research.
"This study does not say precisely that this volcanic activity is what killed the dinosaurs. What we are adding to the conversation is global volcanic activity during the known environmental crisis."
The study is published in the journal Science Advances.