Dinosaur Tracks Found in Alaska

Dinosaur tracks found in Alaska

95 million-year-old impressions in mud

By Krista Mahr

Anchorage Daily News

ANCHORAGE – A retired geology professor was waiting for a boat to pick him up from a riverbank on the North Slope in July 2001 when he saw something unexpected. Bones – big bones.

“Just in those fleeting moments before leaving, I looked down at my feet,” said Don Triplehorn of the University of Alaska Fairbanks, who was southwest of Wainwright at the time. “I looked around and probably in a matter of minutes I picked up four bones.”

The bones were identified as belonging to ornithopod dinosaurs, a group of plant-eaters whose members include the duckbilled herds like those seen in “Jurassic Park” and date back about 95 million years. It was the farthest west that dinosaur bones have been found in northern Alaska.

Last month, Triplehorn returned to the area with Dallas Museum of Natural History curator Anthony Fiorillo to look for more. The expedition found only a few bone fragments but discovered a series of dinosaur tracks a few miles upriver, captured in 95 million-year- old mud.

“We don’t know a heck of a lot of dinosaurs from North America from 95 million years ago,” said Fiorillo, who led the three-man expedition. Fiorillo said the bone and track findings at the two sites fill a chapter in geography and time in Alaska’s paleontology.

They are not the oldest dinosaur fossils found here; two that date 145 million to 150 million years back to the Jurassic period have been found on the Alaska Peninsula and in Katmai. But they are significantly older than the 70 million-year-old bones Fiorillo has been excavating on the Colville River on the North Slope.

“There’s so little done in vertebrate paleontology in the Arctic, especially in the United States Arctic, that every time we go out we find something new,” said Roland Gangloff, interim curator of earth science at the University of Alaska Museum of the North, in Fairbanks.

The trackways, or a sequence of steps, that Fiorillo found in July belonged to three kinds of dinosaurs – an ornithopod, a 20-to- 25 foot theropod, or mostly carnivorous dinosaur, and a smaller 6- to-8 foot theropod.

“Psychologically, they came at a great time,” Fiorillo said. “We weren’t finding bones. The depression wasn’t setting in just yet, but you could see the faces were getting a little long. And then lo and behold.”

Trackways are one of many kinds of fossil evidence of dinosaurs that have been found in Alaska. Individual tracks, impressions of skin, teeth and bones, bite marks on bone, natural molds of bodies, and amber are all other fossils that paleontologists use to help understand when, where and what kinds of animals lived here.

Triplehorn said the tracks were left in “some kind of mud flat that these creatures walked across while it was still damp.”

To remain after millions of years, the material must be “soft enough to take the impression, but not so soupy that it just goes ‘slurp.”‘

Ninety-five million years ago, when dinosaurs still had another 30 million years on Earth, that part of Alaska was probably a conifer forest, with a lush undergrowth of plants. Fiorillo also collected fossils in the area of conifers and leaves, some of which suggested evidence of a forest fire.

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