Arches national park exists in Southern Utah, just north of the Arizona border. It lies atop an underground evaporate layer or salt bed, which is the main cause of the formation of the arches, spires, balanced rocks, sandstone fins, and eroded monoliths in the area. This salt bed is thousands of feet thick in places, and was deposited some 300 million years ago when a sea flowed into the region and eventually evaporated. Over millions of years, the salt bed was covered with debris eroded from the region directly to the northeast. During the Early Jurassic period, desert conditions prevailed in the region and the built up over time.
As this subsurface movement of salt shaped the landscape, erosion removed the younger rock layers from the surface. Over time, water seeped into the surface cracks, joints, and folds of these layers. Ice formed in the fissures, expanding and putting pressure on surrounding rock, breaking off bits and pieces. Winds later cleaned out the loose particles. A series of free-standing fins remained. Wind and water attacked these fins until, in some, the cementing material gave way and chunks of rock tumbled out. Many damaged fins collapsed. Others, with the right degree of hardness and balance, survived despite their missing sections. These became the famous arches.
Rocks have attracted visitors to Arches National Park for thousands of years. However, sightseeing has not been the main activity for very long. Hunter-gatherers migrated into the area about 10,000 years ago at the end of the Ice Age. As they explored Courthouse Wash and other areas in what is now Arches, they found pockets of chert and chalcedony: two forms of microcrystalline quartz perfect for making stone tools. Chipping or knapping these rocks into dart points, knives, and scrapers, they created debris piles that are still visible to the trained eye.
Then, roughly two thousand years ago, the nomadic hunters and gatherers began cultivating certain plants and settled into the Four Corners region. These early agriculturalists, known as the ancestral Puebloan and Fremont people, raised domesticated maize, beans, and squash, and lived in villages like those preserved at Mesa Verde National Park.
While no dwellings have been found in Arches, the northern edge of ancestral Puebloan territory, there are rock inscription panels. Like earlier people, the ancestral Puebloans left lithic scatters, often overlooking waterholes where someone may have shaped tools while watching for game. People living in modern-day pueblos like Acoma, Cochiti, Santa Clara, Taos, and the Hopi Mesas are descendants of the ancestral Puebloans.
Arches National Park is located just north of Moab Utah, an extremely cool town with lots of funky places to eat and outdoor climbing stores. We stayed in the Bowen Motel and escaped the 100+ degree heat and was the first place we did our laundry on the trip.