The Grand Canyon is a steep-sided canyon carved by the Colorado River in the state of Arizona in the United States in the Colorado River basin. It is contained within and managed by Grand Canyon National Park, the Hualapai Tribal Nation, the Havasupai Tribe and the Navajo Nation. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, and visited it on numerous occasions to hunt and enjoy the scenery.
The Grand Canyon is around 277 miles long, up to 18 miles wide and has a depth of over a mile (6,000 feet). For many years, the area has been continuously inhabited by Native Americans who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon (“Ongtupqa” in the Hopi language) a holy site, and made pilgrimages to it.
Temperatures on the North Rim are generally lower than those on the South Rim because of the greater elevation (averaging 8,000 ft above sea level). Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon (State Route 67) is limited during the winter season due to road closures.
The scenic grandeur of Grand Canyon stirs awe-inspired emotion in the millions of visitors who make their way every year to northwestern Arizona. Hardly anything else in the world gives such insight into the geologic timescale of the earth better than this “hole in the ground.” And no other natural wonder causes more contention either.
Layer after layer of exposed strata provide a spectacular sight for each Canyon guest. The lowest and first of the four major divisions of rock units is made up of many types of granite, including the Zoroaster Granite, and the Granite Gorge Metamorphic Suite, which includes the Vishnu Schist, forming the crystalline basement of igneous and metamorphic rocks, respectively. Directly above them is the second major division, which is called the “Grand Canyon Super Group”, it has tilted layers of strata showing evidence of tectonic activity. The third major division contains horizontally stratified layers in the walls of the Canyon made up of sedimentary deposits in nine distinct layers. The fourth major division includes very localized strata which were deposited on the erosion surface on top of the Kaibab Plateau, and consist of river gravels, lake sediments, landslide deposits, and lava flows. Throughout many of the layers exposed in the walls of Grand Canyon, one can find fossils of marine organisms such as brachiopods, corals and mollusks, as well as sometimes the fossilized footprints and track-ways of amphibians and reptiles, ferns, and other plants. Many of these show evidence of a rapid burial.
Written by Jamie Tomkins