A Folsom projectile point, up to 11, years old, was found just west of the Park in The first to leave a distinct trace were the Anasazi and Fremont peoples, similar cultures that inhabited the Colorado Plateau from about A. Arches National Park is just outside the Fremont cultural area, so the most common vestiges of ancient society are Anasazi. Within the park are many superb examples of rock art left in hidden canyons by prehistoric artists; dwelling sites and associated artifacts are also found.
The Arches area was inhabited later by two different historic groups of Native Americans, the Ute and the Navajo. Utes lived and hunted throughout the park area, and were responsible for driving out the first white settlers in the area as late as the s. Arches was on the northern fringe of the Navajo lands, and although they passed through the area there is no evidence that Navajos lived within the park area.
The Old Spanish Trail passed through the Spanish Valley, where Moab is now located, and crossed the Colorado River just outside the park boundaries, but it is unlikely that many Spaniards ever ventured into the park.
Juan Maria de Rivera, a Spanish trader, passed nearby as early as , and by the s the trail was a well-used route from New Mexico to California. Mountain men were known to travel in the area, but the only one known to have entered the present-day park boundaries was the enigmatic Denis Julien, who left an inscription dated in the Devil's Garden area of the park.
The first Mormon explorers entered the Moab area in , and returned to found the Elk Mountain mission the following year; however, they were quickly driven out of the area by the Utes. The Arches National Park lies on top of a salt bed which underwent extreme climate changes millions of years ago. The debris from floods and ocean waters compressed into rock, pushing the earth upward into domes and down into hollow pockets. Faults also occurred such as the park's Moab Fault — one of the most highly studied geologic zones in the country.
Vertical arches resulted from these conditions, and the only rock layers that weren't eroded away with time still stand today. Petrified sand dunes can also be found here which indicate where ancient lakes covered the area. One of the most famous arches in the park is Delicate Arch. This arch has become widely recognized as a symbol of Utah, appearing on a U. Postage stamp and the state license plates. This sandstone formation stands alone, unlike most arches in the park.
The largest natural arch is Landscape Arch, which is a thin ribbon of rock spanning feet in length. Underneath Arches National Park lies a salt bed layer, which was deposited some million years ago when the area was part of an inland sea. When the sea evaporated, it left salt deposits; some areas collected over a thousand feet of these deposits. During the next millions of years, the area was filled with debris deposited from winds, floods, streams and oceans that came and went.
Over time this debris compressed into rock. Over the millennia erosion has created more than 2, arches in the park, ranging from small, three-foot spans to Landscape Arch , which measures feet from base to base. Salt under pressure is unstable, and the salt bed below Arches began to flow under the weight of the overlying sandstones. This movement caused the surface rock to buckle and shift, thrusting some sections upward into domes, dropping others into surrounding cavities, and causing vertical cracks which would later contribute to the development of arches.
As the subsurface movement of salt shaped the surface, erosion stripped away the younger rock layers. Water seeped into cracks and joints, washing away loose debris and eroding the "cement" that held the sandstone together, leaving a series of free-standing fins. During colder periods, ice formed, its expansion putting pressure on the rock, breaking off bits and pieces, and sometimes creating openings. Many damaged fins collapsed.
Others, with the right degree of hardness and balance, have survived as the world famous formations of Arches National Park. We're just the latest batch of humans to be amazed by Arches.
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