Dinosaurs Were Thriving Before Asteroid Impact

Strategic Insights -

Scientists have made a groundbreaking discovery in New Mexico, suggesting that the dinosaurs were still flourishing in the last millennia before the Chicxulub asteroid impact. A trove of fossilized dinosaurs, dominated by the large Alamosaurus, has been dated back to the very end of the Cretaceous period. This contradicts the long-held idea that dinosaurs were in decline before the mass extinction event.

The analysis, conducted by researchers from Baylor University and the University of Edinburgh, shows that the dinosaurs found near Farmington in New Mexico are of the same age as Tyrannosaurus and Triceratops fossils found in North Dakota and Montana. This indicates that a range of species was still alive and thriving in the final millennia of the dinosaurs. "They were not in decline -- these were vibrant, diverse communities," said Daniel Peppe, a professor of geosciences at Baylor University.

The discovery counters the idea that there was a long-term decline in dinosaur diversity leading up to the mass extinction. The findings suggest that the asteroid impact was the main cause of their extinction. Researchers used the fact that the north and south magnetic poles have flipped many times in Earth's history to date the age of rocks. This allowed them to say with high certainty that the dinosaurs found in New Mexico lived in the last few hundred thousand years of the Cretaceous, before the asteroid hit.

Key Takeaways:

  • The dinosaurs found in New Mexico are of the same age as Tyrannosaurus and Triceratops fossils found in North Dakota and Montana.
  • The dinosaurs were not in decline but were thriving and diverse in the final millennia of the Cretaceous period.
  • The asteroid impact was the main cause of the mass extinction, not a long-term decline in dinosaur diversity.
  • The researchers used the fact that the north and south magnetic poles have flipped many times in Earth's history to date the age of rocks.
  • The dinosaurs were still "doing great and thriving" in large numbers with a wide variety of species when the asteroid arrived.
  • The study notes that the previous hypotheses of dinosaur decline before the asteroid's impact underappreciated their true taxonomic and ecological richness.
  • The mass extinction event led to a rapid establishment of mammalian faunas within a few tens of thousands of years.

Statistics:

  • 180 million years: The length of the dinosaurs' reign as the dominant beasts on land.
  • 66 million years ago: The time when the Chicxulub asteroid impacted the Earth, leading to the mass extinction of non-avian dinosaurs and 75% of all life on the planet.
  • 80 tonnes: The weight of the Alamosaurus, a large, long-necked dinosaur.
  • 50 feet: The height of the Alamosaurus.
  • 100,000 years: The time period during which the dinosaurs lived in the last few hundred thousand years of the Cretaceous, before the asteroid hit.
  • 10s of thousands of years: The time period during which mammalian faunas established themselves after the mass extinction event.

Sources:

  • "Fossils of dinosaurs found in New Mexico date back to the very end of the Cretaceous period", published in the journal Science.
  • Interview with Daniel Peppe, professor of geosciences at Baylor University.
  • Interview with Andrew Flynn, lead author of the study.
  • "Scientists find fossils of thriving dinosaurs before asteroid impact", article by Lindsay Zanno, paleontologist at North Carolina State University.