Geologic Tour of New Mexico

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.

Percha Dam and Caballo Lake State Parks, located south of the town of Truth or Consequences, offer striking views of the Caballo Mountains and Red Hills, prominent uplifts in the southern Rio Grande rift. The Percha and Caballo dams were built for the Bureau of Reclamation’s Rio Grande Project in 1918 and 1936–38, respectively. Percha Dam, although only 18.5 feet tall, diverts water into the Rincon Valley, irrigating farmland where much of New Mexico’s famous green chile is grown, along with many other crops. Two miles upstream, the 96-foot-tall and 4,590-feet-wide earth-fill Caballo Dam stores water released from hydroelectric- power generation at Elephant Butte Dam and regulates delivery of that water to downstream users during irrigation season.

The Tyrone mining district, the second largest porphyry copper deposit in New Mexico, is located 10 miles southwest of Silver City in the Burro Mountains of southwestern New Mexico. Native Americans initially mined turquoise from the area around 600 AD. Underground mining was established in the early 1860s and the current mode of mining, open-pit stripping, began in 1968. The mine became part of Freeport-McMoRan in 2007. Parts of the pit are currently being reclaimed.

Cabezon Peak is one of the best-known and most visible landmarks in northwest New Mexico. This giant volcanic plug is visible for tens of miles in all directions, and as far away as Placitas. Cabezon means “big head” in Spanish, and it is aptly named. It is the largest of several dozen widely scattered rocky monoliths, called the Rio Puerco necks. Rising above the Rio Puerco valley floor, they are some of the best-preserved examples of volcanic necks in the world. The craggy black peaks stand in sharp contrast to the sparsely vegetated, buff-colored lowlands from which they emerge. Mt. Taylor looms majestically to the southwest, Mesa Prieta borders the valley to the east, and the Jemez Mountains are visible to the north. This starkly beautiful landscape is unique in New Mexico. At an elevation of 7,786 ft, Cabezon Peak towers more than 1,100 ft above its base, and 2,000 ft above the Rio Puerco nearby.

This small park, established in 1916 by presidential proclamation, offers a close-up view of one of the most perfectly preserved cinder cones in North America. The road to the summit provides access to the summit crater, and if you have ever wanted to walk into a volcano, Capulin Mountain is one of the few places you can do so. A 0.2-mile-long trail from the summit parking lot descends to the vent at the bottom of the crater. The view from the crater rim encompasses all of northeastern New Mexico as well as parts of Texas, Oklahoma, and Colorado.

Heron Lake State Park is located approximately 9 miles west of Tierra Amarilla. Heron Dam was built on Willow Creek near its confluence with the Rio Chama in 1971. This earth fill dam, which is 276 feet tall and 1221 feet long, is designed to create a reservoir to store and deliver San Juan-Chama Project water. The water is used to maintain the recreation pool at Cochiti Lake, some 120 miles downstream on the Rio Grande. The San Juan-Chama Project, managed by the Bureau of Reclamation, takes water from tributaries of the San Juan River, which lies to the west of the Continental Divide, to augment the natural flow of the Rio Grande, which is east of the Continental Divide. The water flows through the Azotea Tunnel under the Continental Divide to Willow Creek, then to Heron Reservoir and the Rio Chama, a tributary of the Rio Grande. The diversions began in 1970, delivering an annual average of 94,200 acre-feet of water to the Rio Grande. Water users include the City of Albuquerque, the City of Santa Fe, the Middle Rio Grande Conservancy District, and the U.S. Department of Energy. The lake can hold 399,980 acre-feet at a crest elevation of 7,192 feet. Heron Lake State Park has been designated a "quiet lake", where boats travel at "no-wake" speeds.

The Carrizozo Malpais are one of the youngest volcanic features in the state of New Mexico. The Malpais, which are the 75 km-long black feature in the satellite image, are basaltic lava flows, such as are being erupted today in Hawaii. State highway 380 traverses the Carrizozo Malpais, and this road provides good access to people who want to view, or visit the lava flows. The Valley of Fires Recreation Area is located on the Carrizozo Malpais.

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.

Bottomless Lakes State Park is located 14 mi southeast of Roswell, on the east edge of the Pecos River valley. The park is 4 mi long, and the loop drive is 9 mi long. The park consists of approximately 1,611 acres and includes eight of nine lakes; the Fin and Feather Club owns Dimmitt Lake, the southernmost lake. Vaqueros (cowboys) who could not find the bottom of the lakes reportedly gave them their name (Young, 1984). They would tie two or three ropes together and drop them into the lakes to try to reach the bottom. The ropes were not long enough, so the vaqueros thought the lakes were bottomless! The greenish-blue color created by algae and other aquatic plants also added to the illusion of great depth.

Caballo Lake State Park is located approximately 14 miles south of the town of Truth or Consequences. Caballo Reservoir is on the Rio Grande in south-central New Mexico east of Interstate 25 between Socorro and Las Cruces.

Camping, picnicing, and boating facilities are available at this state park. Caballo Lake State Park is the third largest state park in New Mexico. This park is generally quiet compared to Elephant Butte State Park to the north.