Fossils in Denali National Park and Preserve
Many national parks and protected lands in the United States have fantastic fossils, but few people think of coming to Denali to see dinosaurs. After years of searching, the first dinosaur fossil was found in Denali in 2005 when a college student from Fairbanks found a footprint only a few yards from the park road!
Click the links below to discover more fossils in Denali and what they can tell us about the Earth long, long ago.
- The Lower Cantwell Formation
If you are lucky enough to find a fossil in Denali please leave it where you find it, but feel free to take pictures!
The Lower Cantwell Formation
The dinosaur fossils in Denali are found in the Lower Cantwell Formation. These rocks were formed 65 to 80 million years ago as small rocks, sand, and mud filled a large basin. Rivers and streams, similar to the ones we see today in the park, brought these sediments from the mountains into the basin for 15 million years. This process formed the fine and coarse layers of shale, sandstone, and conglomerate seen today in the grey outcrops throughout the park.cantwell formationcantwell formationcantwell formationImages: Nearly-vertical outcrops of the Lower Cantwell Formation with hundreds of dinosaur track imprints. (NPS Photo)
How Fossils are Made
Seventy million years ago, when dinosaurs, plants, and other creatures lived in the area we now call Denali, they left footprints, burrows, and leaves in the soft mud. Most of the fossils in Denali are trace fossils, also known as ichnofossils. Trace fossils record evidence of life left behind by animals, such as footprints or burrows, but do not preserve the body of the animal. In addition to animal traces, scientists have found whole pieces of fossilized wood and leaf imprints. Traces are preserved when the imprints are filled in with sediment that hardens into rock over many, many years. Later, the rock must be exposed by uplift and erosion so that humans can find the fossils hidden within the layers.
Paleontology and Paleontologists
Paleontology is the study of ancient life. Paleontologists study fossils for clues to how animals and plants lived in the past. Fossils can teach us about what types of ecosystems existed and how organisms evolved. They are also used to search for oil and date rock layers. Scientists can even use fossilized plants to tell what the climate was like 70 million years ago.
The first dinosaur footprint was found in Denali in 2005, and hundreds of dinosaur footprints have been found by both visitors and scientists since. In some places in the park there are thousands of dinosaur footprints on a single slab of rock! Dinosaur footprints are valuable because they give us clues to how dinosaurs moved and lived.
Denali's Big Bird: Magnoavipes denaliensis
These tracks were probably made by a bird that is five feet tall! The print, belonging to a wading bird, didn't match any previously known fossil, so paleontologist Tony Fiorillo had the honor of providing a name. Fiorillo named the large bird "denaliensis" after the very large mountain, Denali.
Wood, leaf imprints, and other plant remains are the most common fossils found in the Cretaceous Formation. When traveling through the park today, we see large areas covered by tundra and low lying bushes. 65 million years ago, however, a warmer climate allowed trees and other plants to grow much larger than they do now.
The most common fossils in Denali are dinosaur footprints and plant material, but there were many other creatures that left evidence of their existence. The traces of these critters, although smaller and harder to find, are just as important as the large dinosaur footprints. They help to complete the picture of what the ecosystem in Denali looked like 65 million years ago.
Did You Know?
The vast landscapes of interior Alaska are changing. Large glaciers are receding, permafrost is melting and woody plants are spreading. Comparison of "then-and-now" photographs and data from major vegetation monitoring should allow detection, understanding and potential management of these changes.