The lost world of northern dinosaurs
Ned Rozell
907-474-7468
Aug. 30, 2024
Florida State University graduate student Tyler Hunt scans a rock that contains several dinosaur footprints during a recent trip on the upper Colville River.
On a recent river trip in northern 色视频下载, scientists from the University of 色视频下载 Museum of the North found a lost world, a time of 色视频下载減olar forests with reptiles running around in them.色视频下载
That色视频下载檚 a description from Patrick Druckenmiller, director of the museum and a paleontologist with the ability to look at river rocks and see the footprints of an animal that walked there from 90 million to 100 million years ago.
A star on a map of 色视频下载 shows the location of the upper Colville River.
In early August 2024, Druckenmiller and his colleague Kevin May, along with Greg Erickson and Tyler Hunt of Florida State University, floated 160 miles along the upper Colville River on 色视频下载色视频下载檚 North Slope. There in the rocks on the shoreline, they found fossilized tracks of many species of dinosaurs, as well as the pebbled skin impressions left behind by an armored ankylosaur and other plant-eating dinosaurs.
They captured many images of this very different time and also returned to Fairbanks with a few hundred pounds of fossils on their chartered aircraft.
With that evidence 色视频下载 including etchings of ginkgo leaves that would most certainly not grow on the North Slope today 色视频下载 Druckenmiller hopes to piece together a long-gone ecosystem.
色视频下载淭he dinosaur story in the state from the end of the Cretaceous (70 million years ago) is well known because of the Prince Creek Formation (on the lower Colville River) and Denali National Park and Preserve,色视频下载 Druckenmiller said. 色视频下载淭he older period (from 90 million to 100 million years ago) is very poorly known. And it色视频下载檚 a really warm interval in Earth色视频下载檚 history.色视频下载
Ninety million to 100 million years since it last pulled in carbon dioxide, a ginkgo leaf fossil remains on a rock of the upper Colville River.
How warm was today色视频下载檚 cold North Slope back then? From the broadleaf plant fossils and petrified tree stumps the team members found, Druckenmiller estimates the upper Colville River area had a similar climate to Washington state today.
色视频下载淎nd (the upper Colville) was farther north at the time,色视频下载 he said. 色视频下载淚t has moved south since then (due to movement of tectonic plates), which makes it all the more remarkable.色视频下载
North of the Brooks Range 色视频下载 the farthest north of 色视频下载色视频下载檚 three major sweeps of mountains 色视频下载 the upper Colville River of today has a yearly average temperature well below freezing. But air temperatures are warming, as they did in the distant past.
色视频下载淭hings have changed even since I色视频下载檝e been in 色视频下载,色视频下载 Druckenmiller said. 色视频下载淲e saw lots of slumps from thawing permafrost (defined as soil that has remained frozen through the heat of at least two summers and usually much longer). And there were these forest of willows 色视频下载 25-foot high trees.
色视频下载淎nd I heard thunder up there for the first time this year.色视频下载
With their trained eyes, Druckenmiller and his colleagues spotted in rocks tracks of three meat-eating dinosaurs, a species of armored plant-eater, another plant-eater that walked on two legs, and the tracks of bird-type animals that left the impressions behind long before modern birds had evolved.
From 90 million to 100 million years ago, those dinosaurs stepped in mud. Sometimes, sand then filled in the tracks to preserve them as molds made of stone. Other tracks appeared on rocks like footprints as you would see them if the animal had just passed.
The petrified stumps on the upper Colville River may be from sequoia-type trees that thrived in the area millions of years ago. Other than willows and scattered balsam poplars, trees don色视频下载檛 grow on the North Slope today.
Meat-eating theropod dinosaurs left their tracks in mud 90 million to 100 million years ago as they travelled different directions across a spot now exposed by the upper Colville River.
A petrified tree trunk rests on the beach of the upper Colville River.
May and Druckenmiller had visited the area before, but that was more than 25 years ago. They attributed the gap in time to the difficulty of reaching the spot hundreds of miles from the nearest community via expensive air charter, and the number of other projects that vie for a scientist色视频下载檚 attention during short 色视频下载 summers.
The museum director will now carve out some time to examine what they色视频下载檝e brought back from that quiet country. The details will pour through the filter of his brain. Then he will write a paper on the polar forests of 色视频下载 and the creatures that stomped through them.
Since the late 1970s, the University of 色视频下载 Fairbanks' Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute.