Grand+Canyon

=Grand Canyon= By: Sadie and Nick

[[image:http://agrandcanyonvacation.com/wp-content/uploads/2009/12/grand-canyon1.jpg width="360" height="239" caption="Grand Canyon 10"]]
[Grand Canyon] 10

Where: North-Weastern Arizona Colorado Plateau [1]
Its unique geologic significance has made it a national treasure to look at and study for it shows 3 ears of geological times in fossils and rock types and erosion. [1]

You will want to learn about the canyons layers with in the Canyon for they are the highlighted features of the Grand Canyon. [1]

[Grand Canyon] [Topography of Grand Canyon] 10

Topograpahy: It has a elevation of 9,165 feet and the lowest point is at lake Mead at 1,173 feet, It is, on average, 4,000 feet deep, but its deepest point is 6,000 feet, and there is a vertical relief of 7,992 feet. The Canyon extends 277 miles long with a width that ranges from 4 to 18 miles. 2 & 8 [Colorado River] 10 Trails: Three of the most traveled trails are the Bright Angle Trial, the Kaibab Trail, and the Grandview Trail. The Bright Angle Trail decends to the Colorado river on a 9.5 mile route. The Kaibab Trail is a 6 mile route and usually people hike down this trail and then up the Bright Angle. The Grandview Trail is a 3 miles and descends 2,600 feet. There is no water on the Grandview Trail but the sights are said to be wonderful. 3 [Bright Angle Trial] 10

The Grand Canyon is made of exposed bedrock of many different layers form the 3 geological eras of the Proterozoic, the Paleozoic and the geologic. From top to bottom it consists of Kaibab limestone, Toroweap Formation, Coconino sandstone, hermit shale, Supai Group, Redwall Limestone, Mauv limestone, Bright Angle shale, Tepeats Sandstone, and Vishnu Schist. 4 Most of these types of rock are sedimentary, the sandstone and shale most likely formed by mechanical weathering while the limestones could form by either the meachanical weathering or sometimes chemical. the sandstone is usually form dunes which form on the coast of land bodies near ocean. The shale layers are from the ocean floor where marine organism would die and compress together over time creating shale. 9 The reason some ocean layers are in the Grand canyon is because of the deposites of a series of advancing and retreating ocean coast lines. As the climate warms and cools, ice caps melt and form causing the sea level to rise and lower. Therefore, when the sea level rises it submerges the land area. This is why there are so many sedimentary layers, because each of the layers are from a different time in history where the sea level came in and submerged the land and then retreated. The theory of continental drift, that the earth is made up of plates and they are constantly moving, also means that it collected different layers from different converging plates the plate of the Canyon interacted with. Another factor that influences the layer so oceanic sediment are the different types of fossils they found in each layer. 8

[layer of the Grand Canyon] 10

How the features formed: Erosion: 4 Erosion by water: Since the soil is baked by sun it tends to become very hard and cannot absorb water when it rains. The plants in the Canyon also have shallow roots because they don’t usually get much water therefore they cant hold the soil in place. So with those two factors combined, when it rains the water is forced to go down the Colorado River causing huge chunks out of the Canyon to eroding away.

Erosion by ice: Water gets into cracks in rocks form seismic activity, as the season change from hot to cold the water is continuously frozen and thawed. When the water freezes it expand and pushed the rocks apart and widens the crack so that eventually rocks are weathered away.

Colorado River: The Colorado river consists of a lot of water because of the accumulation of melted snow and unabsorbed rain. When this large amount of water is forced through a narrow gorge it ends up carrying away a lot of the debris which scratches at the bottom and side of the river causing it to widen and cut down deeper into the lover rock layers.

Because the Canyon is made of different types of rock, some rocks erode at different times. This creates the different shaped slopes throughout the canyon, because the rocks that erode away fast create a vertical slope while other slow eroding material create a gentler slope.

SUMMER:
The south rim ranges from 50-80 degrees fahrenheit, snow showers and cool nights are common even in the summer months. The North Rim is cooler then the South Rim and snow falls there through the year. The Inner Canyon however is very hot and can exceed 100 degrees. WINTER: There is snow and ice throughout the winter. The South Rim ranges form 18-41 degrees, while the North Rim varies from 16 to 36 degrees and the inner canyon ranges from 36 to 56 degrees. 5 The change in temperature is due to the fact that as altitude decreases temperature increases because there is more pressure the further you go down because there are more air molecules and increased pressure makes it hotter. As you go up you will experience adiabatic cooling due to air molecules expanding due to the decreasing pressure.

Biome: 8
The Canyon is a Desert Biome. Although the North Rim is a cold desert due to its snow in the winter. there is different types of vegitation at the different altitudes of the Canyon. The land alone the river consists of mostlt trees and plants such as: Coyote willow, seep willow, western honey mesquite, and arrowweed. As you climb higher in elevation the majority of vegetation changes to desert scrub such as: creosote bush, brittle brush, ocotillo, big sagebrush, and mariola. At altitudes of 6,200 feet grow piñon pine, Mormon tea, banana yucca, Indian ricegrass, and Utah agave. The North and South Rim contain New Mexico locust, Gambel oak, and elderberry. Then lastly at 8,299 feet, englemann, spruce, and some types of fir are common. The higher the elevation the more desert like the vegetation becomes to withstand the harsh climate. Most of the plants are shrubs that are close to the ground and can bare the harsh heat and lack of water. Although there are more trees at the bottom because of the water source of the river and less trees and more ground plants at the top because it is colder. Two hundred fifty bird species are found in the inner canyon, come including the bald eagle, peregrine falcons, spotted owl, and swifts. In the eastern part of the part you will find the endangered California condor. The valley contains mostly mammals such as beavers, coyotes, spotted skunks, raccoons, mountain lions, mule deer, and bighorn sheep. River otters and muskrats have become extremely rare. Most of these mammals come out at night because it is cooler than the normal hot day. During the day small animals will burrow because the ground acts as an insulator from the hot out side. The birds, to accomodate for the harsh winter migrate up the river.

Human Impact:
Several animas are endangered such as Desert tortoise, great horned owl, and the California Condor. There is also a lot of mass wasting due to the many constructions near the area. There was also been changes in rapids due to the Glen Canyon dam. Damming the Colorado River caused the Glen Canon, which lies to the north of the dam, to became flooded and has subsequently created the large reservoir called Lake Powell. 7

Sources: 1. []

2. []

3. []

4. [|http://www.bobspixels.com/kaibab.org/geology/gc_geol.htm]

5. http://www.desertusa.com/gc/gc_map.html

6. http://www.nps.gov/archive/para.biology.html

7. www.sciencelog.com/community/older/ .../ 199600484.html

8. http://www.pacificnorthwestjourneys.org/year3/downloads/pdf/Biomes/biome9.pdf

9. http://geology.com/rocks/sedimentary-rocks.shtml

10. http://images.google.com/