Geologic Tour of New Mexico — Physiographic Provinces

West of the flocks of birds and birdwatchers along the wetlands of the Rio Grande, a story of cataclysmic volcanic eruptions, ancient dune fields, and long-gone towering mountains lie quietly awaiting visitors to the Bosque del Apache National Wildlife Refuge. The Chupadera Wilderness Trail and the Canyon Trail traverse this geologic record in the contemplative solitude of a wilderness setting, affording “rockwatchers” a quick trip through millions of years of Earth history.

Villanueva State Park lies in the western portion of San Miguel County and straddles the Pecos River where it enters a narrow canyon one mile south of the village of Villanueva. At the park, reddish-yellow and tan cliffs of sandstone tower up to 300 feet above the park and the river. The rocks in these cliffs tell a geologic story of ancient landscapes and seas. Younger gravels on benches along the river and the topography of canyon itself carry this narrative to the present day.

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.

Leasburg Dam State Park is adjacent to Fort Selden State Monument 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.

Ute Lake State Park was established in 1964 at a cost of approximately $5 million and was named after Ute Creek, one of the tributaries of the Canadian River that is impounded by a dam. The small town of Logan is on the east side of the lake, and the lake extends upstream in both the Ute and Canadian Rivers. It is 25 miles northeast of Tucumcari on US–54, NM–39, and NM–540 and is approximately 20 miles west of the Texas–New Mexico state line. Most of the land surrounding Ute Lake is private. All the water is open to the public. The park is in the Pecos Valley section of the Great Plains physiographic province. It lies on the north edge of the Llano Estacado or “staked plains.”

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.

Coronado State Monument is about 15 miles north of Albuquerque in Bernallio and is named after Francisco Vasquez de Coronado, a Spanish explorer who was in New Mexico in the mid-16th century. Coronado supposedly wintered at Kuana Pueblo, the large pueblo preserved at the state monument, between late 1540 and early 1541; however, recent excavations indicate that the Spaniards camped nearby at Santiago Pueblo, located about 2 miles to the southwest of Coronado State Monument. Nonetheless, the preserved pueblo is impressive and the kivas at Kuana Pueblo are decorated with remarkable murals that can be viewed at the Visitor's Center.

The Prehistoric Trackways National Monument is located in the Robledo Mountains just northwest of Las Cruces in Dona Ana County, south-central New Mexico. It contains rocks of Permian age, from the Late Paleozoic Era. They are composed of sediments deposited about 280 million years ago, before the age of the dinosaurs. These rocks contain major deposits of fossilized footprints made by numerous amphibians, reptiles, insects, and crustaceans, as well as plants and petrified wood. Some scientists have called these features the most scientifically significant Permian tracksites in the world. These fossils provide important information about animal behavior in this ancient tropical environment on the edge of the supercontinent Pangea.

The country in northwestern New Mexico between Cuba and Farmington is a land of contrast. Flat grassy plains are cut by valleys that expose the multi-colored moonscapes that we call badlands. The largest area of badlands in the region that is readily accessible to the public is the Bisti/De-Na-Zin Wilderness, popularly known as the Bisti Badlands. The badlands are generally exposed in a series of east to west-trending valleys formed by the tributaries that feed to the south to the north-flowing Chaco River.

The many fossils preserved in this region make this one of the best places on Earth to study the fascinating story of the end of the age of dinosaurs and the beginning of the age of mammals. These fossils will not be obvious to casual visitors, but visitors will be instantly struck by the spectacular scenery of this area, which has been featured in books, magazines, calendars, and websites.

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.