New research shows that the oldest Alaska dinosaurs just got a whole lot older. Scientists from the University of Alaska Fairbanks have confirmed that dinosaur tracks on the Alaska Peninsula date back to the Jurassic Period, 150 million years ago. That’s 50 million years earlier than the oldest dinosaur fossil previously found in Alaska.
University of Alaska Museum of the North Earth Sciences Curator Patrick Druckenmiller said the three-clawed footprints found in sandstone probably belong to a human-sized, meat-eating dinosaur.
Scientists can’t name the species of dinosaur, he said. “There’s a famous saying, there’s only one way — you’d have to find a skeleton at the end of those footprints,” Druckenmiller said.
Before the dinosaur’s tracks were dated, the earliest known dinosaur fossils in Alaska came from the Cretaceous Period, 100 million years ago.
The older tracks decorate a rock face near Chignik Bay, 450 miles southwest of Anchorage, on land owned by the Chignik Lagoon Native Corp.
A group of geologists discovered the tracks in 1975 while mapping the area. They photographed the site but did not collect any data. Druckenmiller said the rocks appeared to be from the Jurassic era, but with no geologic evidence they had no official way to tell.
He said his predecessor at the museum had tried to coordinate a trip to the area. However, funding was never found.
Druckenmiller was able secure support from the U.S. Fish and Wildlife Service, which manages the surrounding Alaska Peninsula Wildlife Refuge. Chignik Lagoon Native Corp. granted permission to work on its land.
Druckenmiller and a crew of four others — paleontologist Robert B. Blodgett, geologists Sarah Fowell and Paul McCarthy and the museum’s Kevin May — visited the site in June.
Druckenmiller said the pilot told him the valley they explored had the highest concentration of brown bears on the planet.
“We had to be careful of one large carnivore to study another extinct one,” Druckenmiller said.
Blodgett had worked with the scientists who found the site in the ‘70s, but the team was not certain of the precise location. The scientists had not left detailed directions.
The 2010 team also didn’t know if the site would still exist.
“The tracks were found 35 years ago; (we were) not sure they’d be there,” Druckenmiller said.
While scientists were able to find the same rock, based on a picture Druckenmiller carried with him, it had eroded greatly. Almost half the vertical slab had broken away.
The footprints were still intact, though. Druckenmiller took molds of the prints. Geologists collected rock samples.
Blodgett, who studies invertebrates, said fossilized bivalves called Buchia mosquensis found at the site date back to the late Jurassic Period, the name geologists give the time between 142 million and 205 million years ago.
Blodgett said the Chignik area is known for its Jurassic rock formations. That alone was enough for them to suspect that the dinosaur prints were from the period.
“It’s a real ‘Jurassic Park,’” he said. “But it’s cold.”
Druckenmiller thinks more fossils could be located in the area and has received reports of dinosaur prints in other wildlife refuges on the Alaska Peninsula. He hopes to do more research next summer.
“There may be some other cool surprises waiting for us,” he said.
Author: Suzanna Caldwell | Source: Newsminer [December 10, 2010]