Jemez Mountains in the context of "Santa Fe National Forest"

The Southern Rocky Mountains are a major subregion of the Rocky Mountains of North America located in the southeastern portion of the U.S. state of Wyoming, the central and western portions of Colorado, the northern portion of New Mexico, and extreme eastern portions of Utah. The Southern Rocky Mountains are also commonly known as the Southern Rockies, and since the highest peaks are located in the State of Colorado, they are sometimes known as the Colorado Rockies, although many important ranges and peaks rise in the other three states. The Southern Rockies include the highest mountain ranges of the Rocky Mountains and include all 30 of the highest major peaks of the Rockies.

The Southern Rocky Mountains are generally divided from the Western Rocky Mountains by the Green River and the Colorado River below the Green River. The Southern Rockies are divided from the Central Rocky Mountains by South Pass in Wyoming and the drainage running east from the pass down the Sweetwater River and the North Platte River; and the drainage running southwest from the pass down Pacific Creek and Sandy Creek to the Green River. This divide between the Southern Rockies and the Central Rockies provided the lowest elevation traverse of the Rocky Mountain region for the historic Oregon Trail, the Mormon Trail, and the California Trail. The southern end of the Rocky Mountains are considered to be the Jemez Mountains and the southern Sangre de Cristo Mountains of New Mexico. Mountains south of here in N.M. are classified as the Arizona/New Mexico Mountains ecoregion using the EPA Ecoregions System.

The Pajarito Plateau is a volcanic plateau in north central New Mexico, United States. The plateau, part of the Jemez Mountains, is bounded on the west by the Sierra de los Valles, the range forming the east rim of the Valles Caldera, and on the east by the Puye escarpment, which rises about 300 to 400 feet (90 to 100 m) above the Rio Grande valley about a mile (1.6 km) west of the river. The Rio Grande passes through White Rock Canyon to the southeast, and the Caja del Rio (Cerros del Rio) across the river is sometimes regarded as part of the plateau. The plateau is occupied by several notable entities, including Bandelier National Monument, the town of Los Alamos and its remote suburb White Rock, and Los Alamos National Laboratory. Elevations range from about 5,600 feet (1,700 meters) at the river to about 7,800 feet (2,400 meters) where the plateau merges into the mountain range.

The Pajarito Plateau is primarily composed of Bandelier Tuff, a voluminous deposit of volcanic tuff laid down in an explosive eruption — in this case, a pair of eruptions from the nearby Valles Caldera. The two ignimbrite-forming eruptions occurred about 1.6 million and 1.2 million years ago and ejected about 300 cubic kilometers of rock each. The orange-pink rock formations constituting the resulting ignimbrites are known as the Otowi and Tshirege Members of the Bandelier tuff. The tuff lies on top of a volcanic field, exposed to the east, which used to be continuous with the Caja del Rio (now across the Rio Grande).

The Bandelier Tuff is a geologic formation exposed in and around the Jemez Mountains of northern New Mexico. It has a radiometric age of 1.85 to 1.25 million years, corresponding to the Pleistocene epoch. The tuff was erupted in a series of at least three caldera eruptions in the central Jemez Mountains.

The Bandelier Tuff was one of the first ignimbrites recognized in the geologic record, and has been extensively studied by geologists seeking to understand the processes involved in volcanic supereruptions.

Bandelier National Monument is a 33,677-acre (136 km) United States National Monument near Los Alamos in Sandoval and Los Alamos counties, New Mexico. The monument preserves the homes and territory of the Ancestral Puebloans of a later era in the Southwest. Most of the pueblo structures date to two eras, dating between AD 1150 and 1600.

The monument comprises 50 square miles (130 km) of the Pajarito Plateau, on the slopes of the Jemez volcanic field in the Jemez Mountains. Over 70% of the monument is wilderness, with over one mile of elevation change, from about 5,000 feet (1,500 m) along the Rio Grande to over 10,000 feet (3,000 m) at the peak of Cerro Grande on the rim of the Valles Caldera, providing for a wide range of life zones and wildlife habitats. 3 miles (5 km) of road and more than 70 miles (110 km) of hiking trails are built. The monument protects Ancestral Pueblo archeological sites, a diverse and scenic landscape, and the country's largest National Park Service Civilian Conservation Corps National Landmark District. Two-thirds of the park, 23,267 acres (9,416 ha), is designated as the Bandelier Wilderness Area. Motorized travel and permanent structures are forbidden in the Wilderness.

The Valles Caldera (or Jemez Caldera) is a 13.7-mile-wide (22.0 km) volcanic caldera in the Jemez Mountains of northern New Mexico. Hot springs, streams, fumaroles, natural gas seeps, and volcanic domes dot the caldera landscape. The highest point in the caldera is Redondo Peak, an 11,254-foot (3,430 m) resurgent lava dome located entirely within the caldera and surrounded by moat-like flows of rhyolitic solidified lavas. Located within the caldera are several grass valleys, or valles, the largest of which is Valle Grande (locally /ˈvaɪ.eɪ ˈɡrɑːndeɪ/ VY-ay GRAHN-day), the only one accessible by a paved road. In 1975, Valles Caldera was designated as a National Natural Landmark by the National Park Service with much of the caldera being within the Valles Caldera National Preserve, a unit of the National Park System. The area has a varied history involving cultural significance, economic resources, scientific studies, and complex geological setting.

The Puye Formation is a geologic formation exposed east of the Jemez Mountains of northern New Mexico. Radiometric dating constrains its age to between 5 and 2 million years, corresponding to the Pliocene epoch.