Geologic Tour of New Mexico

Angel Peak, a 7000-foot pinnacle capped by sandstone, is a prominent landmark near Bloomfield in northwestern New Mexico. It is in the northern part of the San Juan Basin, a large structural depression that formed starting about 75 million years ago during compressional Laramide deformation. The San Juan Basin was surrounded by mountainous uplifts to the north (now buried by the 35 to 20 Ma San Juan volcanic field in southwestern Colorado) and to the east that also formed by Laramide-related compression. The sediments that can be seen at Angel Peak National Recreation area were eroded off of the old Laramide highlands and deposited in the basin 50 to 65 million years ago. More recently, over the course of the last 5 million years (or less), the westward-draining San Juan River, a tributary to the Colorado River, has eroded the rocks of the San Juan Basin. Drainages feeding into the San Juan River have carved the scenic landscape we see today.

Tsiping, also called Tsi’pin or Tsi’pinouinge, is a remarkable pueblo ruin located on Pueblo Mesa near the village of Cañones in the northern Jemez Mountains. Although the site is on Santa Fe National Forest land, the site is off limits unless you have a permit. Permits can be obtained from the Coyote Ranger Station.

Tsi’pinouinge means “village of the flaking stone”, a reference to the village’s proximity to lithic-source quarries in the Pedernal Chert on Cerro Pedernal. Based on tree-ring measurements and ceramic styles, Tsiping was occupied between 1200 AD and 1325 AD, during the Classic Period. Tsiping was the northernmost and largest of the Classic Period pueblos. The village had somewhere between 335 to 400 ground floor rooms, sixteen kivas, and a central plaza. Cavate dwellings are located on the southeastern side of the mesa.

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.

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.

El Vado (“the ford”) Lake lies upstream of a place along the Rio Chama in north central New Mexico where a resistant sandstone ledge in the upper part of the Cretaceous Dakota Sandstone crosses the river. The narrow canyon through this sandstone ledge facilitated passage across the Rio Chama prior to construction of El Vado dam. The Middle Rio Grande Conservancy District completed the construction of El Vado dam in 1935 to store irrigation water in order to honor Native American water rights of the six Middle Rio Grande Pueblos. The dam was updated in 1953-1954 and the outlets were modified in 1965-1966 to accommodate increased flows associated with San Juan-Chama Project.

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.

Ghost Ranch is located approximately 38 miles northwest of the town of Española, New Mexico, just north of U.S. Highway 84, and is run by the Presbyterian Church as a conference center. It has facilities for lodging and camping, as well as paleontology and cultural museums. It lies in the Chama Basin, a broad shallow basin along the eastern margin of the Colorado Plateau in the transition between the Plateau and the Rio Grande rift.

America's newest national park (as of December 2019), White Sands is famous for its extensive sea of white gypsum dunes—indeed, it is the largest gypsum dune field in the world. Located in the southern Tularosa Basin, the park was established as a national monument in 1933 and encompasses nearly 176,000 acres (275 square miles, including 115 square miles of gypsum sand dunes). The park not only contains the large dune field but also a saline mudflat called Alkali Flat, a smaller ephemeral salt lake (or playa) named Lake Lucero, parts of the gypsum-dust plains east of the dune field, and alluvial fans from the surrounding mountains. The dune field and Alkali Flat extend more than 12 miles to the north of the park onto the White Sands Missile Range.

Also see the White Sands National Park sample chapter from our popular field guide: The Geology of Southern New Mexico's Parks Monuments and Public Lands.

Conchas Lake State Park was established in 1955 and named after the Conchas River, one of the tributaries of the Canadian River. It is 24 mi north of Newkirk and 31 mi northwest of Tucumcari on NM–104 and NM–129. Conchas is Spanish for shells and was applied to a group of Indians living in the area when Spanish explorers arrived in the 17th century. The word conchas may be a corrupted name that is confused with the Spanish word conchos, a term also used to describe the Native American tribes in northern New Mexico.

The dam that formed Conchas Lake was the 17th dam in the country built by the U.S. Army Corp of Engineers. One of the state’s oldest dams, it was completed in 1939 to control floods, store water for irrigation and local supplies, and assist in local economic recovery from the Depression.

City of Rocks State Park is truly a geologic monument; it is formed by large sculptured rock columns (pinnacles) or boulders rising as high as 40 ft and separated by paths or lanes resembling city streets. About 34.9 million years ago a large volcano erupted, forming the rocks in an instant (geologically speaking); then erosion over millions of years slowly formed the sculptured columns that now provide a natural playground for children and adults alike. City of Rocks State Park was established in May 1952 to preserve this geologic wonder.