Denali

= __Denali National Park__ = Amy Hedlund and Sara Taylor


 * Introduction**

Denali National Park in Alaska, about a 4 hour drive from Anchorage, has a larger area than the state of New Hampshire. It is 200 miles south of the Arctic Circle, at around 63 degrees north latitude. The most unique thing about Denali is that it is the home of Mt. McKinley, the tallest mountain in all of North America with a height of 20320 feet. 6 Mount McKinley is the highlight of the park, and it lies on the Denali fault. 4 Within Denali National Park there are a number of trails for hikers to travel. These trails range in difficulty and round trip time. One trail is Horseshoe Lake, which hiked a total elevation 200 ft. 5 For those more experienced hikers, Mount Healy is a more difficult trail in which you travel an elevation of 1,700 feet. 5 Also, there is only one road within Denali that is about 90 miles long, which only allows private and authorized cars after a couple miles in. 2


 * Geologic Setting**

During the Paleocene Epoch, magma cooled underneath Earth’s surface to form McKinley pluton. 5 A pluton is a large intrusion of igneous rock that has cooled under the Earth's surface. The park used to be covered by a sea, so that see deposited a lot of sediment where the park is today. Later, in this area tropical forests grew that made the area have a lot of coal that is mined today. Overtime, the land rose and shook, from a lot of heat and pressure, and metamorphic rock was formed. 4 Denali lies on the border of the Pacific Plate, with oceanic crust, and the North American Plate, which is continental crust. The Oceanic crust is denser and so it sub-ducts under the North American Plate. Thus, through out history, the pacific plate has acted like a conveyor belt and moved the ocean floor to the Denali land. 4 The plates pushing against each other create compressional stress which pushes the land upward to form the Alaskan Mountain Range. The bedrock in this situation is a granite batholith that used to be deep in the earth. The granite batholith pushed through weaker sedimentary rocks to the surface and now forms Mt. McKinley. 4

5 One of Denali's small glaciers, East Fork Toklat glacier

There are many agents of erosion within Denali National Park. There are many glaciers within Denali that cover 1/6 of the park's land, and these glaciers are the main agent of erosion. 6 These are Mountain glaciers, not continental glaciers, and are relatively smaller than Greenland and Antarctica. However, The Kahiltna Glacier is the longest in the Alaska Range with a length of 44 miles. Glaciers are the most influential agent and constantly shape the park's mountain landscape. 6 They flow from points of high elevation to low elevation, carving out U-shaped valleys like the Chulitna Valley. 3 Along with glaciers, there are many rivers within Denali. These rivers are bad for any wildlife because they carry and transport and deposit large quantities of glacial silt and till. 5 These rivers, such as the Chulitna River, are braided and have milky waters. 3

6 A Breaded river within the national park

Because Denali lies on the Denali Fault, it is subject to many earthquakes. Because the stress comes from compression stress, the head wall moves down, creating a thrust fault. In November of 2002, an earthquake with a Moment Magnitude of 7.9 started Susitna Glacier Thrust fault, which is in the southern part of the Denali Fault System. This earthquake had a before shock that October on the Denali fault, with an epicenter around 22 km away. 1


 * What is the climate in Denali?**

4 In Denali, the temperature has a very large range. In January, the average temperature is about 2º F, and in July, the temperature is 55ºF. The temperature is so cold in the winter because the day time is so short. The shortest day Denali has ever had was in December. That day only had 4 hours and 21 minutes of daylight 4. The reason why the days are so short are because the northern hemisphere is facing away from the sun. The summer's are much warmer than the winters because the time of day is much longer. 4 The longest amount of daylight Denali has ever experienced was in June and the day was 20 hours and 49 minutes. In addition, the average amount of precipitation per year is around 15 inches (at the park's headquarters). 4 The wettest month's are June, July, and August. During the winter, when it is too cold to rain, it snow's about 78 inches per year (at the park's headquarters). Snow fall has been recorded in every moth of the year in Denali, 2 but October and November have the most snowfall. 4 2


 * Biomes**

The life in Denali's taiga biome is very much adapted to the long winters. The Growing season within Denali is quite short, and many years some plants do not grow enough to produce seeds for the next growing season 7. But still, there is lush vegetation which includes: As well as slow growing trees like willow trees, and dwarf perenials. Most of these plants bloom in June because of harsh winters and springs. 4 This is because Denali is so close to the arctic circle, in the winter the days are almost completely dark. In addition to vegetation, wild life also exists within Denali. 7 Some of these animals that are adapted to the harsh winters include moose, black and grizzly bears, and caribou. 2 With there thick coats of fur, theses animals are able to survive through the very cold and harsh winters. In the park, there are over 200 species of wild life, 167 of which are bird population. 4  Caribou within Denali National Park
 * Spruce
 * Boreal forest
 * low shrubs
 * blueberries
 * low bush cranberries
 * crowberries


 * Human impact on Denali**

With more C02 from humans, there is an excess of green house gasses, creating a thicker layer of gases. When earth's re-radiates some of the sun's radiation, this terrestrial radiation is getting tapped and takes longer to leave the Earth's atmosphere, this is because CO2 is a selective absorber and will absorb earths radiation and send it back at the earth. The longer it is trapped, the more it heats up Earth, which causes Earth's temperature to rise. Since Earth's temperature is rising, the zone of accumulation will not accumulate more snow that that is melting in the zone of wastage (there is more snow melt than snow fall). 5 Thus, the glacier's in Denali are shrinking. Specifically, the Kahiltna Glacier is shrinking in size each year.


 * Sources:**

1. Alaska Earthquake information Center, <[]> 2. Alaska Scenes,  3. Alaska State Parks, [] 4. Danali Education Packet, The US Department of the Interior, [|http://www.nps.gov/dena/forteachers/upload/Ed%20Packet%20-%20color %20%28slight%20edit%202009AL%29.pdf] 5. Denali National Park Hiking Guide, < http://www.denali.national-park.com/hike.htm#hike> 6. Denali National Parks and Preserves, The National Parks Service  7. World Biomes, .
 * 2) "Index of /site_media/photos/2008/09/25." //BringFido.com - Pet Friendly Hotel & Dog Travel Directory//. Web. 10 June 2010. .
 * 3) "Nature & Animal Wallpapers - Hi-Res Wildlife and Scenery Photos - Alaska Range, Denali National Park, Alaska." //Nature & Animal Wallpapers - Hi-Res Wildlife and Scenery Photos - Home//. Web. 10 June 2010. .
 * 4) Web. 6 June 2010. .
 * 5) Web. 10 June 2010. .
 * 6) Photos taken by ourselves