Dinosaurs once thrived in North America, coinciding with a dramatic jump in one vital element

There was a time millions of years ago when dinosaurs roamed the land and thrived across North America, even into the tropics.

Just imagine for a moment a magnificent long-necked dinosaur striding across the land that would one day become New York City or Washington, D.C.

But now we’re learning that the reason dinos were in such great abundance on the North American continent has a great deal to do with the fact that oxygen levels rose dramatically, which allowed for dinosaurs to have the perfect conditions for them.

The fossil of an Allosaurus, which was discovered in Utah (Via Utah Online Library)

A new study from a team of researchers at the Rensselaer Polytechnic Institute and the University of Texas Austin has verified the increase in oxygen levels using a new technique to analyze tiny amounts of of gas that were trapped inside rocks from the Colorado Plateau and the Newark Basin. The rocks dated from 215 million years ago.

As SciNews notes:

“’We tested rocks from the Colorado Plateau and the Newark Basin that formed at the same time about 621 miles (1,000 km) apart on the supercontinent of Pangea,’ said Rensselaer Polytechnic Institute’s Professor Morgan Schaller, lead author of the study.

“’Our results show that over a period of around 3 million years, the oxygen levels in the atmosphere jumped from around 15% to around 19%. For comparison, there is 21% oxygen in today’s atmosphere.’

“’We really don’t know what might have caused this increase, but we also see a drop in carbon dioxide levels at that time.'”

At one time, a Brontosaurus such as this one could also be found in North America (Via Matt Bilden/Warren Air Force Base)
Starting Small


The first dinos to appear in North America were small, according to Professor Schaller:

“’What is remarkable is that right at the oxygen peak we see the first dinosaurs appearing in the North American tropics, Chindesaurus.'”

What did Chindesaurus look like? He was about 6.6 feet (2 m) long and nearly 3.3 feet (1 m) high. And though he was indeed one of the smaller specimens that walked the the continent during the Late Triassic period, as oxygen levels increased over time.

Chindesaurus, the first dinosaur that appeared in North America (By Jeff Martz via Wikimedia Commons)
Utahraptor by Emily Willoughby via Wikimedia Commons CC BY-SA 3.0

All of this happened over a period of about three million years, which is incredibly fast when it comes to geologic time, with the oxygen levels jumping dramatically and the first dinosaurs appearing in North America.

And all of this is also a reminder of a much larger point that shouldn’t be lost on us today: Dinosaurs once ruled the Earth, but then they disappeared.

There’s long been speculation as to what might have killed off the dinosaurs — ranging from the impact of gigantic asteroid to a dramatic change in climate — but one thing is certain: They did vanish and were never seen again. Is this to be humanity’s fate, too, if we fail to address the many critical issues which confront us?


For more on North American dinosaurs, watch this video:

Featured Image via Pixabay



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