Alaska Paleontology

National Fossil Day 2021 features dinosaur footprints from Denali National Park and Preserve.

Lots of parks have fossilized tracks or other impressions known as trace fossils. Trace fossils, or ichnofossils, are the evidence of the biological activities and behaviors of past life. These kinds of fossils include footprints, burrows, nests and scat. Trace fossils are distinct from body fossils, which are the physical remains of plants and animals (such as wood, bones or shells). Trace fossils are an important source of information on ancient environments, the distribution of where ancient life occurred and how lifeforms changed over time. They also provide information on soft-bodied animals that are rarely found as body fossils.

Trace fossils have been documented in many of our national parks and monuments representing biological activity spanning back more than a billion years of geologic time. At Grand Canyon National Park (Arizona), a rich record of life has been identified from trace fossils dating back to the Precambrian (roughly 1.2 billion years ago) to the Early Permian (275 million years ago). For the Mesozoic, fossil tracks left by early dinosaurs have been identified from parks such as Arches National Park and Zion National Park (Utah). At Death Valley National Park (California) thousands of mammal tracks have been identified from the Pliocene epoch approximately 6 million years ago. At White Sands National Park (New Mexico) playa lake deposits preserve tracks showing a co-occurrence of late Pleistocene megafauna (mammoths, sloths, camels, etc.) and early humans in North America.

A panoramic shot of Fossil Point in Lake Clark National Park and Preserve.
Fossil Point in Lake Clark National Park and Preserve.


Fossils tell the story of ancient life. Alaska has a rich paleontological heritage and geologic history. Listen to a story produced by Alaska Public Radio from August 12, 2019 on Arctic Dinosaurs and Ancient Ecosystems, featuring Dr. Anthony Fiorillo and Dr. Paul McCarthy and their work in Alaska parks.

The following are some highlights of Alaska parks fossils:

Coastal cliffs between Cook Inlet and the eastern side of Lake Clark National Park and Preserve hold fossil remnants of 150 million years of sea life.

The rocks that make up Kenai Fjords National Park have sometimes been carried great distances. Some rock was once coral reef close to the equator: It was carried along as the Pacific plate rotated counterclockwise, traveling north, transforming en route to stone. In the far western end of the park, a mixture of chert and basalt scraped from the ocean floor is jumbled with spectacular white blocks of limestone that carries fossils matching those found in China and Afghanistan.

Yukon-Charley River National Preserve has animal fossils from the Precambrian Era. In 1976 scientists discovered one-celled organisms, jellyfish, and flatworms in this area that are estimated to be 700 million years old.

Surveys of Katmai National Park and Preserve taken near Naknek Lake and Brooks Camp found flowering plants from the Tertiary unit that are estimated to be 50 million years old.

Fossils from the Quaternary Period of the Cenozoic Era have been found in The Bering Land Bridge National Monument. These fossils are mainly from the last ice age that happened about 12,000 years ago. Fossils of mammoths, horses, bison, trees, beetles, various marine life, and a prehistoric beaver dam have all been found. Researchers have found pollen cores at Imuruk Lake that date back 100,000 years.

The rocks forming most of the trough of Glacier Bay National Park and Preserve date to the Paleozoic era. The Willoughby Limestone, the oldest rock formation in Glacier Bay, was formed some 425 million years ago in the Silurian period. The Willoughby Limestone and associated formations may represent the thickest known sequence of Silurian rocks in North America, and perhaps the world. The huge, spectacular fossils preserved in the formation indicate that it formed in a very productive, warm, and shallow marine environment.

Aniakchak National Monument holds the Chignik Formation that includes dinosaur footprints and fossils of marine animals dating back 77-68 million years ago. The dinosaur footprints are the only evidence of dinosaurs in all of southwest Alaska.

Gates of the Arctic National Park and Preserve has invertebrate fossils--coral, brachiopods, and trilobites--dating back 400 million years ago during the Devonian Period of the Paleozoic Era. Other fossils found include bison and mammoths (each about five million years old), shark teeth, and other marine fossils from the Triassic and Cretaceous periods.

Denali National Park and Preserve is home to the fossilized remains of many plants and animals that have lived here through time. The 70-million-year-old Cantwell Formation, in particular, is so rich in fossils that a complete ecosystem has been reconstructed from this Cretaceous Period rock.

Learn more about fossils and paleontology in the National Park Service.

Learn more about paleontology in Alaska

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    Last updated: October 12, 2021