The Grand Canyon

The Grand Canyon is a canyon in Arizona carved out by the Colorado River over thousands of years. A canyon is a deep gorge cut between high cliffs by weathering or erosion. The Grand Canyon is 277 miles long, over a mile deep and up to 18 miles wide. The river is continuing to deepen and widen the canyon.

The Kali Ganaki Gorge in Nepal is much deeper, but the Grand Canyon has some outstanding features. Its overall size is quite awe-inspiring, and its layers are extremely colorful. Thick layers of ancient rock are well preserved and show the geologic history of the canyon. The canyon is the result of erosion and displays one of the most complete set of rock layers in the world. Scientists can study centuries of geologic history by studying these layers or strata.

The weather varies depending on the elevation, that is, how far above sea level the spot is. Along the river, temperatures are like nearby Phoenix, Arizona, or nearby deserts. Along the top rim where there are forests, snow sometimes falls. A significant amount of rain falls twice a year, although the area is usually dry. In winter, storms from the west and the Pacific Ocean bring rain and snow to the higher elevations. In the late summer, huge waves of water from the southeast cause local thunderstorms. Temperatures vary greatly throughout the year depending on the area and elevation. They can range from 100 degrees down to below freezing.

The air in the Grand Canyon area is very clean. At times, however, it is affected by forest fires or dust storms. Sulphates, soils and organic substances pollute the air sometimes. Sulphate emissions from cities in southern California are carried to the Grand Canyon by westerly winds. Emissions from Arizona copper mines come up from the South. Particles of soil arrive in the Canyon due to windy conditions and dust from the road. Organic particles come from vehicle emissions, forest fires and vegetation in the area.

Hundreds of varieties of plants, fungi, moss and lichen are found in the Grand Canyon National Park. President Theodore Roosevelt was responsible for setting aside large areas in the United States for National Parks to preserve them for future generations. Grand Canyon National Park was founded in 1919. The Mojave Desert influences the western section of the Park, as far as the types of plants which grow. The Sonoran Desert influences the eastern section. On the rims of the canyon pine forests grow. North-facing slopes do not get much sun so the plants which grow there are like those at higher elevations. South-facing slopes contain vegetation like the Sonoran Desert. They receive large amounts of sunlight.

Over five million visitors come to the Grand Canyon National Park every year. 83% are from the United States. The remaining number come from the Netherlands, Japan, the United Kingdom, Germany and Canada. Many visitors participate in helicopter tours, rafting, hiking, running and skydiving. Tourists may camp but should do so in established campgrounds. The North Rim is usually open mid-May to mid-October only due to extreme weather conditions. The South Rim is open all year.

John Wesley Powell gave the canyon the name 'Grand Canyon.' In 1869, he was the first to descend to the floor of the canyon. It had been called 'Big Canyon' or 'Great Canyon' previously. All the Grand Canyon is not within the park borders. Areas surrounding the park which include the Grand Canyon itself are the Kaibab National Forest, the Hualapai Indian Reservation, the Havasupai Indian Reservation and the Navajo Nation. Native Americans have lived in the Grand Canyon and its caves for hundreds of years. The Pueblos called it a holy site. In 1540, Garcia Lopez de Cardenas was the first European to visit.

A: Wyoming
B: California
C: Arizona
D: New Mexico

A: 1902
B: 1876
C: 1978
D: 1919

A: Thomas Jefferson
B: Theodore Roosevelt
C: Franklin Roosevelt
D: Calvin Coolidge

A: Mississippi
B: Missouri
C: Columbia
D: Colorado

A: William Blake
B: John Wesley Powell
C: John Miller
D: Juan Cardenas

A: The air in the Grand Canyon is always very pure.
B: Temperatures range from freezing to about 75 degrees.
C: No one can camp near the Grand Canyon.
D: The Grand Canyon is 277 miles long.

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