Explore Geology
geology fieldnotes title


National Preserve


cover of park brochure

park geology subheading
dogs pulling a sled across the snow
Yukon-Charley National Preserve, Alaska

Timeless Rivers of Interior Alaska
In the deep Interior of Alaska the great Yukon River strikes through bluffs and mountains of an ancient landscape to unmask rocks whose histories reach back a billion years to life’s beginnings on Earth. Axis of the region, the silt-laden Yukon here flows constricted and swift through a great geologic fault. Side-streams tumble from the hinterlands—further passageways long inviting human traffic. Chief among these crystal rivers are the Charley, the Kandik, and the Nation. Flowing first through upland valley, then through stream-cut valley, and finally onto mature floodplain, the Charley offers spectacular unspoiled wilderness scenery.

Arising at some 4,000 feet elevation, it empties into the Yukon only 700 feet above sea level, for an average gradient of 31 foot per mile and average current of 4 to 6 miles per hour. Side-streams have worn away old heights, softening the shapes of all but a few alpine peaks. The 2.5-million-acre Yukon-Charley Rivers National Preserve includes all 106 river miles of the Charley and encompasses its entire 1.1-million-acre watershed.

Eons have passed here without catastrophic change. Today the Yukon-Charley persists as a haven largely untouched by glaciation and mostly free of human imprint. Here are prime breeding grounds of the endangered peregrine falcon, calving grounds of the Fortymile caribou herd, choice paleontological sites, superb recreational waters, and the timeless presence of the mighty and historic Yukon River.

The preserve lies between the communities of Eagle and Circle, Alaska. New Jersey with its 7.5 million residents would fit between those towns, but there are only 30 year-round residents here. Truly isolated, the preserve is wilder and less populated now than it was 50 or 80 years ago. The late-1800s Klondike and Nome gold rushes turned Circle—1980 population 81—into the "Paris of the North", boasting an opera house. Pokes of gold were legal tender. This was the stuff of Jack London's stories and Robert Service's poetry. Eagle's population—about 200 today—soared to 800. Fort Egbert boasted electric lights and hot-and-cold running water. Circle and Eagle were south-bank trade centers on the great Yukon River thoroughfare that bisects Alaska east to west for 1,250 river miles and stretches for 1,979 rider miles from its headwaters near Whitehorse, in Canada's Yukon Territory, to its mouth at the Bering Sea. When not choked with stupendous, lethal spring and fall ice floes, the Yukon serves as summer waterway or frozen winter highway. Ancient humans had traveled through the unglaciated Yukon corridor. Those who stayed probed the uplands for game via the stream-carved valleys. Forays upland took them first through thickets of willow and alder, through stands of white spruce and cottonwood screening the rivers, then across boggy flats punctuated by stunted black spruce. Mixed white spruce, birch, and aspen gave way to brush as the hunters climbed toward dry tundra on the ridges. Above them loomed always the barren mountains scored by scree slopes and topped by granite pinnacles.

What scientists think may be remnant Ice Age vegetation occurs as patches of arctic steppe on sun-drenched benches and bluffs. Now, winter's darkness and cold conspire to congeal this land abutting the Arctic Circle. Animals go to ground or migrate, or, like the mountain sheep, stand hunched against arctic winds. Rivers and streams freeze over. Deprived of silt from these frozen sources, the winter Yukon runs clear under as much as 6 feet of ice. But the sun returns. The rivers break. Birdcalls herald spring. Old cliff eyries of peregrine falcons are refurbished and the swift flight and stoop of these winged hunters take their toll on migrating birds. Salmon begin their runs, first the big kings and then the dog salmon. Here, 1,200 miles from the sea but with many miles left to swim, the powerful fish are still firm of flesh. And as they have for centuries, people gather at fish camps along the Yukon. The people who stayed after the glory days of gold faded—Han Indians already home and recent arrivals who had found a home—settled back to a slower pace, trapping, hunting, fishing, gardening. With easily exploited placer deposits of gold exhausted, mining, too, changed from a rush to long toil. Even today along the Yukon a fish camp may lie just around the bend— fishwheel or net in the water, fish drying on streamside racks. Hunters track moose and caribou, and miners match their mettle against the grudging rock. Life, in all its flintiness, persists here as it has for eons, and a few hardy souls still pit their fortunes against a true frontier wilderness.

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

A geology photo album has not been prepared for this park.

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

books, videos, cds subheading

Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.

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

Information about the park's research program is available on the park's research webpage.

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

Currently, we do not have a listing for any park-specific geology education programs or activities.

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/yuch/index.cfm   I  Email: Webmaster
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