What did Denali look like 100 million years ago, when
dinosaurs roamed instead of moose?

We’d see large flood plains, with braided streams – just like Toklat or any of the rivers on the north side today. Slightly more broad, with greater fluctuation of water. As far as we know it wouldn't have been a tremendous difference from what we have now. Broader plains, from what the rock deposition tells us (the materials that have been deposited by streams and rivers.)

Were the mountains as large during the age of the dinosaurs?
There was probably some mountain – the ancestral top portions of Mt. McKinley – but not as uplifted. The Alaska Range was there – but probably not as high as what we have today. There'd be a few less foothill type mountains.

Today, Denali’s landscape has short summers and cold winters. Was the climate different back then?
Climate-wise, we didn't have much snow. It was quite a bit warmer. There may have been little or no glacial ice. Based on the fossil plant material and pollen we've found, the temperatures probably ranged at the coldest just a bit above freezing. High 30's to 40's Fahrenheit would have been the mid-winter cold spell. Fairly warm summers – 80, maybe 90 or warmer degrees Fahrenheit.

If the climate was warmer, were local plants different than the black spruce, low-lying tundra brush and lichen that grow in Denali National Park today?
We know the biggest trees around were a family of Sequoia. We find the needles, and branches, and petrified pieces of Sequoia, so we know they were common. But we don't know how big they got. We also found cyads – those are palm-like and date-like trees. Not true tropicals. One of the things that was going on at that time was the temperature of the planet was homogenized. In other words, kind of the same anywhere you went.

What environmental factors were responsible for the temperature and climate differences between 100 million years ago and today?
The darkness would have been the same because the tilt of the earth was the same. But the temperature fluctuations were minimized. Primarily because the continents were split up a lot more. There were a lot more oceans. The sea levels were very high. A major seaway split the whole of North America. It came practically to the North Pole. There was ocean here at the time, but what the configuration of the land was then is very difficult to decipher.
Phil Brease in Denali National Park
phil brease

Phil Brease collapsed on a walk while he was guiding a science class from the Healy School on a geologic outing last spring. His geology work at Denali was, literally, groundbreaking.

Denali Park also credits him for his twenty years work in which he led efforts to cleanup and restore mining sites and streams in the Kantishna Area.

Myrospirifer breasei, a species of extinct marine mollusk-brachiopod that has been found only in Denali, is named after him.
Photo, NPS
Phil Brease in Denali
Ancient Animals Of Denali
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When dinosaurs roamed Denali.
In the winter of 2010 we asked Phil Brease about his work in Denali and what had been found. "We haven’t found any bones in the park as we all hoped. We’ve only found trace fossils, which are mostly footprints. Three quarters of the Cantwell Formation is in the park. The Cantwell Formation is the name of the rock that contains the dinosaur trace fossils – and of course, plant fossils."
Since then, however, things have changed and Denali Park has become the center of much of Alaska's dinosaur research.
Denali scenery
Phil Brease Photo, NPS