Geologic Tour of New Mexico — Physiographic Provinces

Jemez State Monument is in scenic Cañon de San Diego, which is located to the southwest of the Toledo and Valles calderas, large collapse features that formed during voluminous volcanic eruptions 1.6 and 1.25 million years ago in the Jemez Mountains. The monument lies near the mouth of Church Canyon, a tributary to the Jemez River within Cañon de San Diego. Two main rock units, the Pennsylvanian Madera Group and Permian Abo Formation, are exposed in and adjacent to the monument (Figures 3 and 4). Both limestone from the Madera Group and sandstone from the Abo Formation were incorporated into the walls of the 15th century pueblo and the 17th century Spanish mission at Jemez State Monument. Large rounded boulders of early Jemez volcanic field basalt and andesite lavas that were eroded from the high cliffs of Cañon de San Diego and carried by the Jemez River and flash floods in Church Canyon to the vicinity of the monument are also included in the walls of the structures.

Navajo Lake State Park, which includes the second largest reservoir in the state, is in the Four Corners region of northwestern New Mexico, 25–30 mi east of Bloomfield. Navajo Dam was built in 1958–1962 by the U.S. Bureau of Reclamation for flood control, recreation, sediment control, and to provide water to the Navajo Indian Irrigation Project, one of the many projects of the basin-wide Colorado River Storage Project established in 1956. The Navajo Indian Irrigation Project, founded in 1962, provides water for approximately 110,000 acres of farmland on the Navajo Indian Reservation. The dam traps water from the San Juan, Piedra, and Los Pinos Rivers and Sambrito and La Jara Creeks. The dam consists of an earth- and rock-filled structure that extends 3,648 ft across the San Juan River and is 402 ft high at an elevation of 6,085 ft. In the reservoir area, five cemeteries, 4 miles of Colorado state highway, and 6.5 miles of railroad were relocated. The city of Farmington has operated a 30-megawatt hydroelectric power plant at Navajo Dam since 1987. When full, the reservoir covers 15,590 acres.

The Zuni-Bandera volcanic field, in northwest New Mexico, has had many episodes of basaltic eruptions over the last million years. The youngest lava flow in the field is the McCartys flow, which is only 3000 years old, one of the youngest volcanic features in the 48 contiguous United States! The Zuni-Bandera volcanic field has produced many basaltic lava flows, some with a-a characteristics, and some that are paheohoe. There are also a number of well-preserved cinder cones that can be visited, as well as many lava tubes, some of which contain perennial ice. The Zuni-Bandera volcanic field is an excellent site for studying physical volcanology of basaltic magmatic systems.

The Bitter Lake National Wildlife Refuge covers about 38 square miles in central Chaves County, east and northeast of Roswell. Situated on the Pecos River where the Chihuahuan Desert meets the Great Plains, the refuge supports an amazing diversity of flora and fauna, including numerous migratory waterfowl in the winter months. Established in 1937, the refuge includes the new Joseph R. Skeen Visitor Center, which sits on the Orchard Park terrace overlooking floodplain wetlands and the redbed escarpment on the eastern skyline.

Beginning at the Visitor Center are a bike trail, a short walking trail, and an 8-mile auto-tour loop. The loop traverses a Pecos Valley terrace overlooking the floodplain for the first 4 miles. The remainder explores floodplain environments, from an abandoned Pecos River meander oxbow lake to the low-lying wetlands. The more adventuresome visitors can explore the refuge’s north tract, which includes the Salt Creek Wilderness. Here, one can hike to the mouth of Salt Creek at the Pecos River and continue onto some of the refuge’s many sinkholes, including the scenic Ink Pot.

Fort Selden State Monument is adjacent to Leasburg Dam State Park on NM–157 (Fort Selden Road) at the Radium Springs exit on I–25, north of Las Cruces. It is an area rich in both geologic and human history. The location was an ancient Indian campground and a crossing point for Spanish caravans headed across the Jornada del Muerto. Living-history demonstrations of 19th century military life at Fort Selden highlight many weekends during the summer. Wildlife viewing, especially bird watching, is popular at the state park. A bird list is available from the park office. In the winter months many species of ducks, teals, snow geese, cranes, herons, egrets, swans, and pelicans migrate through the southern Rio Grande valley and can be seen at the state park. Numerous raptors, including owls, turkey vultures, eagles, and hawks, can be seen hunting in the area. Small mammals common to the park include rabbits, squirrels, chipmunks, rodents, coyotes, and foxes.

Elephant Butte Lake State Park is located approximately 5 miles north of the town of Truth or Consequences. Elephant Butte Reservoir is on the Rio Grande in south-central New Mexico east of Interstate 25 between Socorro and Las Cruces. The 301-feet high and 1,674-feet long concrete dam across the Rio Grande that created Elephant Butte Reservoir is the largest dam in the state of New Mexico. Elephant Butte Reservoir was the largest man-made reservoir in the world when the dam was completed in 1916. The dam is considered a National Historic Civil Engineering Landmark, primarily because the construction of this dam marked the first civil engineering project designed for international distribution of water.

The Valles Caldera National Preserve is one of the most geologically unique and significant areas in North America. The preserve encompasses much of the Valles caldera, a huge volcanic crater that formed 1.2 million years ago during an enormous volcanic eruption that spread ash over large parts of New Mexico. The caldera is located near the summit of the Jemez Mountains, a large volcanic complex in north-central New Mexico. The Valles caldera exhibits world-class examples of the landforms produced by a very large, explosive volcano, and the preservation and exposure of geological features within the Valles is spectacular. Much of what geologists know about large-scale explosive volcanism began with detailed studies of the rocks in the Valles caldera and Jemez Mountains, and the area continues to draw geologists from around the world. Since the eruption 1.2 million years ago, there has been uplift of the crater floor, followed by the eruption of smaller, younger volcanoes called “domes” within the crater left by the large eruption. Since then, the caldera has from time to time been home to a series of large lakes. This dynamic geological history is responsible for the beautiful and unique landscape that we see in the region today.

The 64-mile stretch of narrow gauge railroad track between Antonito, Colorado and Chama, New Mexico was originally built in 1880 as part of the Denver and Rio Grande Western Railroad. This rail line provided much-needed transportation and freight service between Denver and mining camps in Silverton during the late nineteenth and early twentieth centuries. When the Federal Government discontinued the use of the silver and gold standard to back American currency, the "Silver Panic" in 1893 caused the closure of many of the mines in the Silverton area. The railroad continued to operate with revenues from transportation of livestock, timber, and farm produce. The oil and gas industry in the Four Corners region also utilized the railroad. Demand for rail transportation in this region waned by the mid-twentieth century. Passenger service on the Denver and Rio Grande Western Railroad ended in 1951 and freight service ended in 1968. Railroad enthusiasts and legislative bodies in New Mexico and Colorado recognized the scenic splendor of the train route between Chama and Antonito. Through a joint effort, the Cumbres and Toltec Scenic Railroad, complete with coal-powered steam engines carrying tourists in railcars on refurbished narrow gauge tracks, was created in 1970 to preserve this historic and picturesque section of railroad.

Sugarite Canyon State Park, once the site of a thriving coal-mining camp, was established as a state park in 1985, but the canyon has been a recreational attraction in northeastern New Mexico for decades. Sugarite Canyon State Park is located about 5 miles northeast of Raton via NM-72 and NM-526 (paved). The elevation in the park ranges from about 6,900 ft to 8,400 ft. This heavily wooded mountain park has something for everyone year round. Trails are maintained through the ruins of the settlement and past coal dumps and mines.

The craggy gray granodiorite spire of Cookes Peak, the highest point in the Cookes Range at 8,404 feet, is a prominent landmark in southwestern New Mexico. Cookes Spring on the southeast side of the range is one of just a few perennial springs in this part of New Mexico; consequently, this peak was an important marker of water for Native American, Spanish, and American travelers through the region during the 19th century. The peak was named for Captain Phillip St. George Cooke, who led the Mormon Battalion through southern New Mexico during the winter of 1846 while scouting an overland wagon route for the U.S. Army. Later, a Pony Express mail station was established near the spring. Fort Cummings was built nearby in 1863 to protect travelers from Apache attacks; the fort was manned by the U.S. Army off and on until Geronimo surrendered in 1886. Ruins of the Cookes Spring Station of the Butterfield Trail and Fort Cummings are located about a mile south of the present-day Hyatt Ranch.