Anchorage Daily News

FAIRBANKS -- A tunnel carved 30 feet into the frozen bank of the Colville River helped researchers this summer recover some of the best-preserved dinosaur fossils ever found on the North Slope. Some specimens may be from species never before found in Alaska.

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"We're digging in an environment we've never been in before," said Kevin May, a paleontologist and operations manager with the University of Alaska Museum of the North. "And the specimens we're finding are in far better condition."

The banks of the Colville River have been a treasure trove of fossils. Over the years, staff members and students from the Museum of the North have collected more than 8,000 ancient teeth and bones from the area. Most of those specimens, however, were shattered and pulverized by millennia of exposure to freeze-thaw cycles within the top layers of rock.

"The freeze-thaw cycle jacks the rocks apart," May said. "Quite often we find things in four or five chunks."

Researchers from the museum, in conjunction with a team from Australia and a mining crew with Alaska Hard Rock Mining and Blasting, dug a 10-foot-wide tunnel straight into the side of a steep bluff in March.

The team returned to the site in August to begin the meticulous excavation down into the frozen bone bed.

A special arctic entry of sorts at the mouth of the tunnel coupled with the natural cooling of the permafrost kept the temperature in the tunnel at a constant 23 degrees.

Every hour or so, the team members would take a short break outside the tunnel, away from the frigid, cramped conditions.

"We'd warm up, jump around and go back in and keep working," said Amanda Hanson, the curatorial assistant at the museum and a member of the team.

The paleontologists, working in two small plots, were only able to dig about a foot into the frozen ground of the tunnel in three weeks time.

But the slow pace and freezing conditions were worth it, May said. The 100 or so fossils gathered from the tunnel this summer included some of the best ever found in the region and included two specimens that might be from species of dinosaurs never before found in Alaska.

Back in his lab, May showed off a number of the best finds including two tiny vertebrae from the tail of a 70 million-year-old reptile. May hasn't yet been able to identify what species the fingertip sized bones belong to.

"It's something we haven't seen before, I'm pretty sure," he said.

The Fairbanks team also recovered a tyrannosaur tooth, broken in half but otherwise in remarkable condition, May said. Several fine details, including a row of saw-like serrations running along the tooth's edge, were clearly visible in the 8-inch specimen.

Perhaps the most exciting find, however, was discovered on the beach outside the tunnel, May said. He was walking along the river bank when he spotted the fossilized remains of a portion of a pachycephalosaur jawbone.

The remains of a similar dome-headed dinosaur have been found on the North Slope in the past, May said, but this latest find is different. May and his colleagues suspect that the jawbone belongs to a new species.

"It's going to require time and comparison to confirm that," May said. "But it's very exciting. This may be a second species of pachycephalosaur found in the North Slope."

The well-preserved specimens found within the tunnel were even better than May had hoped for and could lead to further breakthroughs in Alaska paleontology.

"The potential for finding very large bones is there," May said.

This summer's dig was supposed to be a one-year experiment to see if the technique of digging down into the permafrost would result in better specimens. However, May and his team plan to return to the site next summer.

"There's enough to keep us in that hole for years," he said.