A trip down the Yukon River this summer yielded big results for one University of Alaska paleontologist.
“We found a ton of dinosaurs, literally!,” Pat Druckenmiller, the Curator of Earth Science at the Museum of the North, said.
He and colleagues floated nearly 500 miles of the Yukon River, where they collected literally 1 ton – or 2,000 pounds – of fossilized dinosaur tracks. It was all shipped by barge from Kaltag back to Fairbanks, where it now awaits further investigation.
Druckenmiller leads the way past shelves of specimens in the basement of the Museum of the North. There are whale skulls, giant bones and at the end of one dimly lit row, huge chunks of sand and mudstone.
“So this is some of what we collected,” he said, balancing a giant, tan colored rock on his knee. “So, this is three toes of a medium sized meat eating dinosaur; and right here, you can see the claw impression at the tip of the toe.”
It looks exactly as one might expect a three-toed dinosaur footprint to look. This is one of thousands of preserved dinosaur tracks Druckenmiller and colleagues discovered this summer.
“This and all of the other material that we found was just a complete surprise, because no one expected anything like this was out there,” Druckenmiller said.
The team put their boats in on the Yukon River at the village of Ruby and floated all the way to Kaltag.
Druckenmiller says part of the surprise is that no one in any of the villages they passed along the way knew what was hidden in the river banks.
“I find it hard to believe that somebody didn’t see these before,” he said. “Maybe they didn’t call them dinosaurs, but somebody must have found some very convincing footprints that made them wonder.”
Research into the area’s geology led some of Druckenmiller’s colleagues to believe they might find something.
“So, they’re Cretaceous age rocks, from the age of the dinosaurs about 90 to 100 million years old and the cool things is they had a lot of plant fossils, leaves from broad-leaved trees and different types of conifers,” he explains. “In other places where we found tracks, this is a great combination of things to expect to find tracks, so sure enough we said let’s go give it a try.”
And the effort paid off.
Other evidence of dinosaurs has been discovered along the Colville River on the North Slope and at Denali National Park, but Druckenmiller says these Yukon River fossils are 25 to 30 million years older.
“That’s interesting because we know climatically that was a warmer period in earth history, Alaska was still farther north than it is today so we know these dinosaurs were living at or above the Arctic Circle when they were alive and because they are older than other tracks in the state we get a sense of how dinosaurs changed through geologic time,” he said.
The discovery includes both meat-eating and plant-eating dinosaurs.
“These are footprints of ankylosaurs,” Druckenmiller said, pulling out another specimen. “Which are plant eating dinosaurs that were armored dinosaurs?”
“They were covered in these little bony plates all over their back and shoulders and head; they have a very distinctive footprint – the hind foot like this one here has four toes and the tracks are generally wider than long and the front foot has five toes and they are about as broad as they are long.”
Druckenmiller can identify some of the footprints based on bones collected from elsewhere in the state.
“But in some cases we don’t know what the track maker was and in fact we have a couple of very strange footprints that we are still investigating and might be really exciting when we figure out what they are,” he said.
Druckenmiller wouldn’t elaborate. He says a new find like this is extremely rare in the 21st century.
“It’s really like doing paleontology as it might have been done a hundred years ago anywhere else in the world where you would be the first person to step and walk onto land and really look at it as a paleontologist and say ‘Wow! What kind of fossils are preserved in this?,’” he said. “So it’s really exciting to be able to do that in Alaska.”
The team has many years-worth of work ahead before they can fully tell the story of the dinosaurs that lived along the Yukon River.