Colorado Plateau in the context of "Stratigraphy"

Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age (i.e., estimated age). In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another. Prior to the discovery of radiometric dating in the early 20th century, which provided a means of absolute dating, archaeologists and geologists used relative dating to determine ages of materials. Though relative dating can only determine the sequential order in which a series of events occurred, not when they occurred, it remains a useful technique. Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate. The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.

Colorado is a landlocked state in the Western United States. It is one of the Mountain states, and Southwestern region of the United States, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, and Oklahoma to the southeast. Colorado is noted for its landscape of mountains, forests, high plains, mesas, canyons, plateaus, rivers, and desert lands. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is the eighth-largest U.S. state by area and the 21st by population. The United States Census Bureau estimated the population of Colorado to be 5,957,493 as of July 1, 2024, a 3.2% increase from the 2020 United States census.

The region has been inhabited by Native Americans and their Paleo-Indian ancestors for at least 13,500 years and possibly much longer. The eastern edge of the Rocky Mountains was a major migration route for early peoples who spread throughout the Americas. In 1848, much of the Nuevo México region was annexed to the United States with the Treaty of Guadalupe Hidalgo. The Pike's Peak Gold Rush of 1858–1862 created an influx of settlers. On February 28, 1861, U.S. President James Buchanan signed an act creating the Territory of Colorado, and on August 1, 1876, President Ulysses S. Grant signed Proclamation 230, admitting Colorado to the Union as the 38th state. The Spanish adjective "colorado" means "colored red" or "ruddy". Colorado is nicknamed the "Centennial State" because it became a state 100 years (and four weeks) after the signing of the United States Declaration of Independence.

The Four Corners is a region of the Southwestern United States consisting of the southwestern corner of Colorado, southeastern corner of Utah, northeastern corner of Arizona, and northwestern corner of New Mexico. Most of the Four Corners region belongs to semi-autonomous Native American nations, the largest of which is the Navajo Nation, followed by Hopi, Ute, and Zuni tribal reserves and nations. The Four Corners region is part of a larger region known as the Colorado Plateau and is mostly rural, rugged, and arid. The largest state in the region is New Mexico, which is the fifth-largest state of the fifty states.

The Four Corners area is named after the quadripoint at the intersection of approximately 37° north latitude with 109° 03′ west longitude, where the boundaries of the four states meet, and is marked by the Four Corners Monument. It is the only location in the United States where four states meet. In addition to the monument, commonly visited areas within Four Corners include Monument Valley, Mesa Verde National Park, Chaco Canyon, Canyons of the Ancients National Monument and Canyon de Chelly National Monument. The most populous city in the Four Corners region is Farmington, New Mexico, followed by Durango, Colorado.

The Rio Grande rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. The rift extends from central Colorado in the north to the state of Chihuahua, Mexico, in the south. The rift zone consists of four basins that have an average width of 50 kilometres (31 mi). The rift can be observed on location at Rio Grande National Forest, White Sands National Park, Santa Fe National Forest, and Cibola National Forest, among other locations.

The Rio Grande rift has been an important site for humans for a long time, because it provides a north–south route that follows a major river. The Rio Grande follows the course of the rift from southern Colorado to El Paso, where it turns southeast and flows toward the Gulf of Mexico. Important cities, including Albuquerque, Santa Fe, Taos, Española, Las Cruces, El Paso, and Ciudad Juárez, lie within the rift.

The Glen Canyon Group is a geologic group of formations that is spread across the U.S. states of Nevada, Utah, northern Arizona, north west New Mexico and western Colorado. It is called the Glen Canyon Sandstone in the Green River Basin of Colorado and Utah.

There are four formations within the group. From oldest to youngest, these are the Wingate Sandstone, Moenave Formation, Kayenta Formation, and Navajo Sandstone. Part of the Colorado Plateau and the Basin and Range, this group of formations was laid down during the Late Triassic and Early Jurassic, with the Triassic-Jurassic boundary within the Wingate Sandstone. The top of the Glen Canyon Group is thought to date to the Toarcian stage of the Early Jurassic.

The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In New Mexico, it is often raised to the status of a geological group, the Chinle Group. Some authors have controversially considered the Chinle to be synonymous to the Dockum Group of eastern Colorado and New Mexico, western Texas, the Oklahoma panhandle, and southwestern Kansas. The Chinle Formation is part of the Colorado Plateau, Basin and Range, and the southern section of the Interior Plains. A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern Utah. The southern portion of the Chinle reaches a maximum thickness of a little over 520 meters (1,710 ft). Typically, the Chinle rests unconformably on the Moenkopi Formation.

The Chinle Formation was probably mostly deposited in the Norian stage, according to a plethora of chronological techniques. It is a thick and fossiliferous formation with numerous named members (subunits) throughout its area of deposition.

The Ancestral Puebloans, also known as Ancestral Pueblo peoples or the Basketmaker-Pueblo culture, were an ancient Native American culture of Pueblo peoples spanning the present-day Four Corners region of the United States, comprising southeastern Utah, northeastern Arizona, northwestern New Mexico, and southwestern Colorado. They are believed to have developed, at least in part, from the Oshara tradition, which developed from the Picosa culture.

The Ancestral Puebloans lived in a range of structures that included small family pit houses, larger structures to house clans, grand pueblos, and cliff-sited dwellings for defense. They had a complex network linking hundreds of communities and population centers across the Colorado Plateau. They held a distinct knowledge of celestial sciences that found form in their architecture. The kiva, a congregational space that was used mostly for ceremonies, was an integral part of the community structure.

Arches National Park is a national park of the United States in eastern Utah. The park is adjacent to the Colorado River, 4 mi (6 km) north of Moab, Utah. The park contains more than 2,000 natural sandstone arches, including the well-known Delicate Arch, which constitute the highest density of natural arches in the world. It also contains a variety of other unique geological resources and formations. The national park lies above an underground evaporite 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.

The park consists of 310.31 km (76,680 acres; 119.81 sq mi; 31,031 ha) of high desert located on the Colorado Plateau. The highest elevation in the park is 5,653 ft (1,723 m) at Elephant Butte, and the lowest elevation is 4,085 ft (1,245 m) at the visitor center. The park receives an average of less than 10 in (250 mm) of rain annually.