Digging for Alaska dinosaurs

October 4, 2007

Courtesy of  Far North Science
By Doug O'Harra

Paleontologist Anne Pasch digs for fossils inside a permafrost tunnel
Photo: Kevin May

The project, coordinated by the University of Alaska Museum of the North, punched the shaft into an extraordinary fossil bed that emerges from the cliffs along the Colville River, the major river that drains the Brooks Range into the Arctic Ocean.

Over the years, scientists have visited these grounds to conduct precarious digs perched on narrow benches and collapsing banks, excavating bit by bit through sloughing scree and muck.

Despite such difficulties, more than 8,000 bits of bone and teeth have been recovered from a dozen extinct families, offering stunning insight into the variety of polar dinosaurs that once thrived in the Far North.

But the scientists always thought there had to be a better way than wading through muck for weathered and broken remnants . This summer, using a technique first developed by paleontologist Thomas Rich in Australia, a shaft was dug.

In August, mining of the Colville's dinosaur bank begun.

And they found dinosaurs fossils deep within.

The dinosaur mine extends 60 feetinto Colville River permafrost
Photo: Kevin May

"These dinosaurs were doing quite well in high latitudes in both hemispheres 110 to 65 million years ago," Alaska paleontologist Roland Gangloff told me a few years ago. "They were exceedingly abundant. Everything we've found says they were in great variety, both herbivore and carnivore."

Over the past two decades, scientists have uncovered evidence of an extraordinary ecosystem at 13 sites in Alaska, Australia, Canada, Siberia, New Zealand and Antarctica. Gangloff and Rich and co-authors described their findings and insights in the perspective Polar Dinosaurs, published by the journal Science in 2002.

Among the two most proflific sites have been the Colville River's permafrost-rich west bank and a rugged cliff face on the sea coast cove at the base of a 300-foot coastal cliff about 100 miles southeast of Melbourne.

"These studies in southeastern Australia and the North Slope of Alaska have yielded tantalizing glimpses of polar dinosaurs and their habitat," wrote Gangloff and Thomas Rich, curator of vertebrate paleontology at the Museum Victoria, and Patricia Vickers-Rich, chair of paleontology at Monash University in Melbourne.

The Riches described their Far South investigations in the book "Dinosaurs of Darkness." It chronicled how they uncovered new evidence of Australia's polar dinosaurs with the help volunteers and a tunnel excavated into solid rock.

Rich argued that Alaskans should build a similar dinosaur mine into the Colville's frozen banks.

"I think you guys are sitting on what could be one of the more exciting dinosaur discoveries on Earth, and hardly anyone knows about it," he told me a few years ago. "You've got the potential right there, but what you need is a technology that takes advantage of the permafrost, that doesn't see it as a barrier but as a plus."

With help from Conoco Phillips, the museum team finally got the shaft dug - a 60-foot tunnel carved into the ancient permafrost.

Here's more detail from an online story by the museum writer Kerynn Fisher:

Anne Pasch (left) and Amanda Hansen (right) digging for fossils in the permafrost
Photo: Kevin May

Over the years, University of Alaska Museum of the North staff, students and volunteers collected more than 8,000 teeth and bones from the area, the most productive dinosaur-bearing area in the world's polar regions.

But most of the specimens were shattered into small pieces after being exposed to millennia of freeze-thaw cycles.

Researchers often wondered what they would find if they dug beyond the active layer of the permafrost. Would they find more intact specimens?

This year gave museum staff and collaborators a chance to test this theory and uncover new ground in dinosaur research as they worked in a 20-meter-deep tunnel dug into the side of the bluff.

The project was no small undertaking. In March, museum staff, colleagues from Australia and a mining crew spent three weeks in the frozen North excavating the tunnel.

Then, they sealed the tunnel, returned home and waited for the summer field season, returning in August when conditions would be more conducive to field work.

When they arrived, they had more work cut out for them: high waters from the spring melt left two feet of ice on the floor of the tunnel.

"We spent the first week just clearing the ice out of the tunnel before we could even begin to excavate the specimens," says museum operations manager and paleontologist Kevin May, one of the principal investigators on the project. "Even after that, the work was slow going."

In three weeks, the museum research team - May, museum earth science curatorial assistant Amanda Hansen, University of Alaska Anchorage geology professor emeritus Anne Pasch, and volunteers Kelly May and Cindy Schraer - excavated approximately 30 centimeters into the frozen ground in two plots, each a meter square. Working outside on the banks, they could have excavated a meter deep in the same amount of time.

The long hours and hard work in the freezing tunnel paid off. The team recovered more than a hundred specimens.

Many of the specimens are in excellent condition, including hadrosaur teeth and bones; tyrannosaurid and troodontid teeth; and tiny vertebrae from an as-yet-unidentified dinosaur species, possibly new to Alaska.

Outside the tunnel, the team also found a pachyceplalosaur jaw fragment, potentially representing a new species. The dinosaurs date to the late Cretaceous period and are approximately 70 million years old.

"This summer's work has given us a much better sense of the size and shape of the Liscomb bed," says May, referring to a productive bone bed discovered in 1961 by Shell Oil Company geologist Robert Liscomb.

"Before this summer, we knew the bed extended along the river bluff for about 100 meters, but we had no idea how far the deposit extended into the bluff. Now, we know that it is at least six meters wide at the tunnel site, and likely even wider. There will be plenty of work there to keep us busy for years to come."