Geologic Tour of New Mexico — Physiographic Provinces

Hyde Memorial State Park lies in the southwestern Sangre de Cristo Mountains in the Santa Fe Range. The north-south trending Sangre de Cristo Mountains are about 225 miles long, extending from near Salida, Colorado, at the north end to just southeast of Santa Fe at the south end (Bauer, 2008). The Sangre de Cristo Mountains are considered to be part of the Southern Rocky Mountain physiographic province. The mountains rise abruptly from the relatively topographically subdued High Plains on the east side. The Rio Grande rift, a northerly-trending zone of continental extension that runs from northern Colorado to west Texas, marks the western boundary of the range. The Santa Fe Range, which is cored by Proterozoic basement rocks, is bound on the north by the Peñasco embayment, on the south by Glorieta Pass, on the west by the Española Basin, and on the east by the Picuris-Pecos Fault just west of the Pecos River. At least four episodes of mountain building are recorded in the Sangre de Cristo Mountains.

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.

Gila Cliff Dwellings National Monument is in the Mogollon Mountains approximately 44 miles north of Silver City, New Mexico. Gila Cliff Dwellings National Monument was established in 1907 and is one of the nation’s oldest monuments. The monument lies within the Mogollon-Datil volcanic field; volcanic eruptions from this field covered 40,000 km2 of southwestern New Mexico and southeastern Arizona with lava and ash flow tuffs 40 to 24 million years ago.

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.

Clayton Lake State Park is approximately 12 mi northwest of Clayton on NM–370 in northeastern New Mexico. Unlike most lakes in New Mexico, Clayton Lake was established in 1955 specifically as a recreational site by the State Game and Fish Commission after construction of the dam. In 1967 the site became Clayton Lake State Park. The lake offers excellent fishing and is stocked with rainbow trout, walleye pike, crappie, bluegills, bullheads, large-mouth bass, and channel catfish by the State Game and Fish Department. Boating is prohibited after the fishing season ends, so from October through April the park is a refuge for waterfowl.

The most exciting geological feature at Clayton Lake State Park is the dinosaur footprints found in sandstone at the dam spillway about 1982. Approximately 500 tracks of at least three species are found at the spillway; most of them pertain to ornithopod dinosaurs (ichnogenus Caririchnium) and theropods. The dinosaurs ranged in size from a baby Iguanodont that was approximately 1 ft long to adults that were 30 ft long. Most of the tracks are of bipedal herbivores or planteaters (Iguanodonts or Hadrosaurs). The kite-shaped tracks were made by Iguanodonts walking in wet mud. Worm borrows, fossilized impressions of plants, ripple marks from waves, and mudcracks are also common.

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.

This is a virtual field trip to the classic Permian reef complex and other geologic features of the Guadalupe Mountains, including those in Carlsbad Caverns National Park and Guadalupe National Park in Texas. It contains an introduction to the geology of the Permian reef complex plus several roadlogs with diagrams and photographs, as well as an extensive bibliography in order to provide a balanced presentation for a geology student audience.

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.

A spectacular, eroded anticline and syncline pair lies between the Ojito Wilderness and the village of San Ysidro in north-central New Mexico. The San Ysidro area lies near the intersection of four significant geologic features, including the mildly deformed Colorado Plateau to the west, the Laramide-age (75 to 55 million years old) Sierra Nacimiento uplift to the north, and the late Oligocene to Miocene Rio Grande rift to east. The northeast-trending Jemez lineament, characterized by young volcanism, cuts across all three geologic provinces. The <15 million year old Jemez volcanic field is visible to the northeast, the 2 to 3 million year old Puerco Necks, including Cabezon Peak, are located just to the west, and the 1.5 to 3.3 million year old Mount Taylor volcano can be seen on the skyline to the west.

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.