Explore Geology
geology fieldnotes title


National Park & Preserve


cover of park brochure

park geology subheading
Photo of a hiker on a glacier at Denali National Park
Denali National Park & Preserve, Alaska

Denali, the "High One", is the name Athabascan native people gave the massive peak that crowns the 600 mile-long Alaska Range. Denali is also the name of an immense national park and preserve created from the former Mount McKinley National Park. The changes in names and boundaries that have occurred over the years can be confusing, as they indicate the way various parts of the park and preserve may be used today. In 1917 Mount McKinley National Park was established as a wildlife refuge. The park and the massif including North America's highest peak were named for former senator—later President—William McKinley. In 1980, the Alaska National Interest Lands Conservation Act (ANILCA) enlarged the boundary by four million acres and redesignated it as Denali National Park and Preserve. At six million acres, the park is larger than Massachusetts. It exemplifies interior Alaska's character as one of the world's last great frontiers for wilderness adventure. It remains largely wild and unspoiled, as the Athabascans knew it.

The Mountain
Mount McKinley has been called the Alaskan landscape's most impressive feature. While you Alaska Range peaks above the Thorofare River may not see this great peak during your stay here, it is there! Mount McKinley is the highest mountain on the North American continent. Measured from the 2,000-foot lowlands near Wonder Lake to its summit, this mountain could be called the tallest in the world. The vertical relief of 18,000 feet, greater even than that of Mount Everest, tops out on the snowy summit at 20,320 feet. McKinley's north summit is North America's second highest peak at 19,470 feet. Temperatures at the summit are severe even in summer. Winter lows at just 14,500 feet can plummet below -95°F! During storms, winds can gust to more than 150 miles per hour. Permanent snowfields cover more than 50 percent of the mountain and feed the many glaciers that surround its base. The mountain's granite and slate core is, in fact, overlain by ice that is hundreds of feet thick in places.

Mount McKinley reigns in lofty isolation over the Alaska Range, that magnificent 600-mile arc of mountains that divides south-central Alaska from the interior plateau. Its life as a mountain range began some 65 million years ago, the result of the Denali Fault, North America's largest crustal break. This fault, where two tectonic plates have moved against each other, stretches for 1,300 miles from the Yukon border down to the Aleutian peninsula. There, the Alaska and Aleutian Ranges meet in a mad jumble of peaks that includes active volcanoes. Earthquake tremors both mild and moderate are frequent occurrences in the park and preserve. The building of these massive mountains began out of a flat lowland. The material that Earth's inner turmoil thrust up has subsequently been eroded, sculpted, and weighed down by huge masses of ice. Numerous glaciers still radiate from the high peaks of the Alaska Range, where the frigid temperatures prevent their melting. Some of the glaciers are visible from the park road. The debris-laden snout of the 35-mile-long Muldrow Glacier lies within a half mile of the park road. The park and preserve owes its beautiful landscape contrasts—wide, low plains and dark, somber mountains, brightly colored peaks and sheer granite domes—to the Denali Fault. Geologists say that Mount McKinley still rises.

The Land
More than 430 species of flowering plants as well as many species of mosses, lichens, fungi, East fork of the Toklat River algae, and others grace the slopes and valleys of Denali. Only plants adapted to long, bitterly cold winters can survive in this subarctic wilderness. Deep beds of intermittent permafrost—ground frozen for thousands of years— underlie portions of the park and preserve. Only the thinnest layer of topsoil thaws each summer to support life. After the continental glaciers retreated 10,000 to 14,000 years ago, hundreds of years were required to begin building new soils, and to begin the slow process of revegetation. Denali’s lowlands and slopes consist of two major plant associations, taiga and tundra.

  • Taiga (pronounced ti-ga), a Russian term meaning "land of little sticks", aptly suggests the scant tree growth here near the Arctic Circle. Much of the park and preserve's taiga lies in valleys along the rivers. White and black spruce, the most common trees are interspersed with quaking aspen, paper birch alder, and balsam poplar. Stands of deciduous trees occur along streamside gravel bars or where soils have been disturbed by fire or other action. Woods are frequently carpeted with mosses and lichens. Many open areas are filled with shrubs such as dwarf birch, blueberry, and a variety of willow species. The limit of tree growth occurs at about 2,700 feet in the park and preserve. For comparison, the elevation at the park hotel is 1,750 feet. Above the tree limit, taiga gives way to tundra.
  • Tundra is a fascinating world of dwarfed shrubs and miniaturized wildflowers adapted to a short growing season. There are two types, moist tundra and dry tundra, with myriad gradations in between.
  • Moist tundra varies in composition: some areas contain tussocks of sedges and cottongrass; others contain dwarfed shrubs, particularly willows and birches.
  • Plants of the dry tundra live scattered among barren rocks at higher elevations. Tiny highlands plants grow closely matted to the ground, creating their own livable microclimate. Flowered dryas, dwarf tireweed, moss campion, dwarf rhododendron, and forget-me-not (Alaska's state flower) dot the rocky landscape, offering stunning summer displays of delicate blossoms. Although small in stature they loom large in importance because their nutrients provide food that sustains even the largest species of park wildlife.

The History
Many generations of native Athabascans wandered over this region before Caucasians began Park tour buses in mid 1930's to discover and explore it. Nomadic bands hunted lowland hills of Denali's northern reaches spring through fall for caribou, sheep, and moose. They preserved berries for winter, netted fish and gathered edible plants. As snows began to fall they migrated to lower elevations, closer to the river valleys' better protection from winter's severe weather. Much of the Alaska Range formed a mighty barrier between interior Athabascans and Cook Inlet Athabascans to the south.

The park was originally established to protect its large mammals, not because of majestic Mount McKinley. Charles Sheldon conceived the plan to conserve the region as a national park. Naturalist, hunter, and conservationist, Sheldon first traveled here in 1906 and again in 1907 with a packer and guide named Harry Karstens. Karstens later made the first ascent of Mt. McKinley's south peak and would serve as the park's first superintendent. Sheldon devoted much of his 1907 travels to studying boundaries for the proposed national park that would include territories suitable for a game refuge. When Sheldon returned to the East in 1908, the Game Committee of the Boone and Crockett Club, of which he was chairman, launched the campaign to establish a national park. Largely due to these efforts, Mount McKinley National Park was established in 1917. Its populations of Dall sheep and other wildlife were now legislatively protected. However, Mount McKinley itself was not wholly included within the boundaries.

Sheldon wanted to call the park Denali, but his suggestion would not be followed until 1980. That year the boundary was expanded to include both the Denali caribou herd's wintering and calving grounds and the entire Mount McKinley massif. More than tripled in size, the park became Denali National Park and Preserve. It was also designated an International Biosphere Reserve significant for its potential for subarctic ecosystems research. Predator-prey relationships exist in balance here as they may have existed elsewhere before human intrusions. Denali National Park and Preserve remains a subarctic wilderness of wildlife and glaciated mountains.

park maps subheading

The General park map handed out at the visitor center is available on the park's map webpage.

For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.

photo album subheading

For information on other photo collections featuring National Park geology, please see the Image Sources page.

books, videos, cds subheading
Cover of Geology of Denali National Park book
The Geology of Denali National Park
Collier, Michael., 1989.
Alaska Natural History Association.
ISBN 0-930931-04-1, paperback, 48 pages, color & b/w photos, charts, drawings.

Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.

Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
ISBN 0-393-92407-6
9" x 10.75", paperback, 550 pages, full color throughout

The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!

Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.

geologic research subheading

For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.

The NPS maintains a searchable data base of research needs that have been identified by parks.

A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.

selected links subheading

NPS Geology and Soils Partners

NRCS logoAssociation of American State Geologists
NRCS logoGeological Society of America
NRCS logoNatural Resource Conservation Service - Soils
USGS logo U.S. Geological Survey

teacher feature subheading

We offer resources for teachers, students, and parents to learn about Denali's natural world and cultural heritage. We have some excellent resources for teachers, suggestions for parents visiting the park with children, and some facts and games for kids. More educational materials will be available at this site in the near future. Check it out, and be sure to come back soon to learn more about Denali.

General information about the park's education and intrepretive programs is available on the park's education webpage.

For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.
updated on 01/04/2005  I   http://www.nature.nps.gov/geology/parks/dena/index.cfm   I  Email: Webmaster
This site is best viewed in Internet Explorer 6.0 or Netscape 7.0