Denali National Park
Alaska
By John Abraham
Where is Denali National Park?
Denali National
Park is located in
South Central
Alaska,
approximately
120 miles away
from Anchorage.
It is the 3rd
largest National
Park in the
United States.
When was Denali National Park Established?
• In 1907-1908, a naturalist named Charles Sheldon came
to Denali to study Dall sheep. He saw that mining and
big game hunters were also coming to the Denali area.
He knew the increase in visitors would not be good for
the natural environment and wildlife and wanted to
protect the area.
• He returned to Washington, DC and proposed that the
area become a National Park to protect the wildlife.
• He was successful and President Wilson signed a bill into
law to make Denali a National Park on February 26,
1917.
Charles Sheldon
How was Denali National Park Formed?
• The oldest rocks in the park date back to the Paleozoic era, about 300-500 million years ago
• The park is located on the Denali fault, an active fault where the Pacific Plate is sliding underneath the
North American Plate. As this subduction happened during the last 100 million years, the mountain
ranges we see today in Southern Alaska were formed. This includes coastal mountain ranges and inland
ranges such as the Alaska Range that includes Denali.
• Denali formed about 70 million years ago when a huge pool of magma several kilometers beneath the
surface cooled very slowly and formed the hard igneous rock, granite. Then, because of it’s location on
the fault, it has been pushed up over millions of years.
• Denali’s neighboring mountains consist of soft rocks (limestone, shale) that weather easily, compared to
the Denali’s granite. This creates a big difference in the heights of Denali and the rest of the Alaska
Range.
Subduction of Oceanic Crust under
Continental Crust
Left: Subduction of Pacific Plate Under North
American Plate in Alaska.
Above: Denali towers over neighboring mountains.
Rocks Found in Denali National Park
• Denali is one of the few mountains in the
world that is made up almost of all one type
of rock. In this case, Denali is made of the
igneous rock, granite.
• Denali’s neighboring mountains in the Alaska
Range are made up of sedimentary rocks.
These are primarily limestone, sandstone and
shale. These rocks are much weaker than
granite and therefore erode faster than
Denali. This creates the large height
difference between Denali and its
neighboring mountains.
Granite
From left to right: sandstone, shale,
and limestone
What are Special Landforms are Inside Denali
National Park?
Denali/Mount Mc Kinley
• Denali (formerly known as Mount Mc Kinley) is the most well known feature inside Denali
National Park.
• It is the tallest mountain in North America at 20,237 feet.
• Denali means “the Tall One” or “the Great One” in Athabascan.
• It is part of the Alaska Range of Mountains.
• The lowest point in the park (at the Yenta River Valley is 200 feet above sea level.
Bodies of Water
• There are approximately 12,200 lakes/ponds and 18,000 miles of streams.
• Wonder Lake – The most well known lake in the Park. It was created by debris from
glacier advance and retreat
• Kettle ponds – Formed when chunks of glacier ice broke off and created a depression that
filled with fresh water
Denali (Mt. McKinley)
Glaciers
• There are at least 40 named and hundreds of unnamed glaciers covering approximately
1/6 of the park.
• Glaciers are located from elevations as high as 19,000 feet down to 800 feet.
• The Kahiltna Glacier is the longest glacier in the park (& the entire
Alaska Range) is 44 miles in length.
Kahiltna Glacier
Flat Lands and Forests
• Tundra at high elevations
• Forests of spruce, poplar and aspen trees
• Glacial erratics – large rocks left behind by ancient glaciers.
Left: Glacial Erratic
Environmental Issues Facing Denali
National Park
Human Development – Alters the natural landscape and brings more humans to places
they wouldn’t normally have gone
Global Warming – Increased global temperatures have caused the glaciers to thin and
melt away.
Air Quality – Pollution from Asia and Europe makes its way to Denali.
Busses travel the paved road
bringing thousands of visitors to the
park.
Exotic Plants – Plants that aren’t native to the park are introduced and are invasive.
They climb and spread over native plants. An example is bird vetch, an invasive plant.
Sound Quality – Human generated noise disturbs the sounds of nature.
Earthquakes – Because of plate tectonics and Denali’s location on the active Denali
fault, strong earthquakes are possible in the park. Earthquakes can damage natural
features and human developments. Denali continues to grow by approximately 1mm
per year.
Migratory Birds – Migration patterns are in danger because of human development and
activity in the park.
Bird Vetch, an invasive plant.
Technologies Used in Denali National Park
• Seismographs – used to study earthquakes in the park and along the
Alaska Range.
• Cameras and motion detectors are being used to observe glacial
changes and animal activity.
• Air quality Monitors – used to study levels of pollution in the park.
• Telemetry put collars on wildlife that send radio signals to tell people
where it is.
• Aerial Surveys They use helicopters and other flying vehicles to take
surveys.
• Weather stations – located throughout the park and help provide
current information for visitors as well as data for studying climate
change.
• GPS Is used to determine were certain things are.
• Internet – Used to inform visitors about the park and share information.
Denali visibility webcam
http://www.nature.nps.gov/air/webcams/parks/denacam/denacam.cfm
Seismograph
Weather Station
How is the Land inside the park
currently changing?
Changes due to Plate Tectonics
• The forces of plate tectonics that created the park continue to impact
the park today.
• The Pacific Plate continues to actively subduct under the North
American Plate at a rate of 2 inches per year.
• These subduction forces result in the mountains continuing to “grow”.
The mountains surrounding Denali grow and weather at about the
same rate. Since Denali does not weather nearly as much as its
neighboring mountains, it actually continues to grow at a rate of 1 mm
per year.
• Earthquake activity along the Denali fault continues to impact the
park’s landscape.
• In 2002, the Denali fault experienced a Magnitude 7.9 earthquake.
• This resulted in cracks in the ground up to 6.7 m (22 feet wide) and
mudslides that move huge volumes of earth.
Road Damage from
2002 Earthquake
Mudslides can move
mountainsides
How is the Land inside the park currently
changing? (continued)
Changes due to Global Warming
• Nearly all glaciers surveyed in Alaska are melting due to increased global
temperatures. Thinning rates in the last 5 to 7 years are more than twice
those seen in previous years. Half of the water flowing into the oceans,
globally, due to melting glaciers, is a result of melting in Alaska.
• The increased temperatures are causing the park’s permafrost regions
(areas frozen for more than 2 years) to thaw. This allows new vegetation
to grow, filling in glacial wash areas and shrinking pond/lake areas.
Changes due to Human Development
• One final area is the impact that man is having on the park. As more
people visit the park, additional facilities are constructed which alters the
landscape. In addition where these visitors go can destroy the delicate
tundra vegetation.
Sunset Glacier, Denali National Park.
Above photo shows the decrease in
glacial ice that has occurred over 70
years. It is important to remember
this glacial ice is hundreds of feet
thick.
Contour Map of Denali National Park
A contour map is a map
illustrated
with contour lines.
This topographic map
shows mountains, hills,
glaciers and important
man made features
such as airports.
Relief Map of Denali National Park
A Relief Map is a
map that shows
topography through
different coloring or
shading. It can also
be three
dimensional. This
map shows the
topography of
Denali National Park.
Note the Alaska
Range, including
Denali, shown in
white at the bottom
of the park.
Experience Denali through its Beautiful
Landscape, Wildlife and Plantlife
Bibliography
http://www.nps.gov/articles/aps-v5-i1-c2.html
www.ohranger.com/denali/preservation
http://www.livescience.com/40595-denali-mount-mckinley.html
http://alaska.usgs.gov/science/geology/images/photo_gallery.html
https://www.denaliwildlifetour.com/park-history/history-of-denali-park/
http://traveltips.usatoday.com/denali-national-park-physical-features-104632.html
http://traveltips.usatoday.com/denali-national-park-formed-13168.html
https://en.wikipedia.org/wiki/Denali_National_Park_and_Preserve
http://www.beautifulworld.com/north-america/united-states/denali-national-park
http://www.nps.gov/dena/learn/nature/glaciers.htm
http://thetrekplanner.com/dnp-glacier-erratics/
http://www.swisseduc.ch/glaciers/alaska/kahiltna_glacier/icons/07_khiltna_crevasses_ponds.jpg
Bibliography (continued)
http://denalinationalparkpink.weebly.com/landform-featuresrocks-andminerals.html
http://www.nps.gov/articles/denali.htm
https://www.nature.nps.gov/geology/parks/dena/
http://www.nps.gov/dena/learn/photosmultimedia/webcams-depot.htm
http://www.nps.gov/articles/aps-v6-i2-c3.htm
http://www.nps.gov/articles/aps-v5-i1-c6.htm
http://www.nps.gov/subjects/bears/evolvingtechnologies.htm
https://en.wikipedia.org/wiki/Seismometer
http://www.wunderground.com/wximage/moyerdestroyer/25
http://www.graylinealaska.com/blog/post.cfm/journey-through-denali-withgray-line-alaska
Bibliography (continued)
http://earthobservatory.nasa.gov/Features/denali/
http://denalirepeatphotos.uaf.edu:8080/index.php/view-photo-pairs/photopair-page?sort=map&sortb=5&id=Mt_Eielson_Thoro_01
http://earthobservatory.nasa.gov/Features/denali/
http://pubs.usgs.gov/fs/2003/fs014-03/
http://www.nps.gov/features/dena/003/landchange/virtual_tour.html
http://denalirepeatphotos.uaf.edu:8080/index.php/view-photo-pairs/photopair-page?sort=map&sortb=5&id=Mt_Eielson_Thoro_01
http://www.nps.gov/dena/learn/nature/climate-change.htm
http://www.onesixtyk.com/denali-national-park/5503/
http://www.nationalgeographicexpeditions.com/expeditions/alaskawilderness-family-tour/detail
http://www.mapsofworld.com/usa/national-parks/