Geologic Tour of New Mexico

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.

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.”

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.

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.

Santa Rosa, "the city of natural lakes", lies in the semiarid, upper Pecos River valley in Guadalupe County where numerous natural artesian-spring lakes abound. Blue Hole, one of these lakes located within the city limits, is well known for its crystal-clear water and attracts scuba divers. However, the largest lake in the area is man made—Santa Rosa Lake, located about seven miles north of the city on the Pecos River. The dam was completed in 1981 at a cost of $43 million for conservation of irrigation water and flood and sedimentation control. The name of the dam was changed from Los Esteros (Spanish for pond or estuary) in 1980 when the state park was authorized.

Manzano Mountains State Park, established in 1973, is located eighteen miles northwest of the town of Mountainair and is south of the village of Manzano in the foothills of the Manzano Mountains. “Manzano” is Spanish for apple and refers to old apple orchards found in the town of Manzano. The apple trees were planted after 1800 as determined by tree ring growth, although local legends claim that the apple trees were planted in the 17th century by Spanish missionaries traveling to the nearby Indian pueblos. The few remaining trees are probably the oldest apple trees in the United States. There are no apple trees at Manzano Mountains State Park, but Gambel oak, Emory oak, piñon, ponderosa pine, and alligator juniper trees are abundant. The alligator juniper is named for the checkered pattern on the bark of older trees, which resembles an alligator's hide. Nearby, Tajique, Torreon, and 4th of July Canyons in the Manzano Mountains contain some of the largest stands of Rocky Mountain and big-toothed maple trees in the Southwest; spectacular fall colors attract visitors from throughout the area. The Manzano Mountains also play an important role as a raptor flyway during spring and fall migrations. Some species of birds may fly 200 miles in a day and several thousand miles in a season. The park has a field checklist available to visitors who enjoy bird watching.

Aztec Ruins National Monument was established in 1923 to preserve the remarkable remains of an ancestral Puebloan farming community, including a twelfth-century Chacoan great house. The settlement flourished from A.D. 1050–1150, at which time it was one of the largest Puebloan settlements in the Southwest, strategically situated between Mesa Verde to the north and Chaco Canyon to the south. Culturally it is considered a Chacoan outlier, at the northern terminus of one of the prehistoric roads that emanated from Chaco. Later occupants (in the 1200s) are thought to have had closer ties to Mesa Verde.

One of the earliest written eyewitness accounts of Aztec Ruins was provided by geologist John Newberry in 1859, who reported at that time that the walls stood 25 feet high. Both the ruins and the setting are spectacular, but the park is perhaps best known for the reconstructed Great Kiva, which was excavated in 1921 and reconstructed by Earl Morris in the 1930s. It is the only restored great kiva in the Southwest and is accessible to visitors; stepping inside provides a unique glimpse of what these ceremonial structures might have been like when they were intact. The park is now a World Heritage Site.

Oliver Lee Memorial State Park, at the mouth of Dog Canyon on the western escarpment of the Sacramento Mountains, opened in 1980, but the area has attracted visitors for several thousands of years. The 180-acre state park has a flowing stream and forms an oasis on the edge of the harsh desert of the Tularosa (Spanish, "reddish willows") Valley. The park is named for Oliver Lee (1865-1941), a prominent rancher and state legislator who settled near the mouth of Dog Canyon in the late 1880s. Lee was active in developing water-control projects in the area. Oliver Lee's ranch is one of the many exhibits at the state park. The Visitor's Center houses displays of the geologic and cultural history of the canyon area. Approximately 30,000 people enjoy camping, hiking, and picnicking in the park each year. An interpretative trail along lower Dog Canyon allows visitors a glimpse of vegetation and wildlife in the oasis as well as several cultural sites. The Dog Canyon Trail starts at an elevation of about 4,500 ft in the state park and climbs the steep escarpment of the Sacramento Mountains to the Eyebrow Trail to Joplin Ridge at an elevation of 7,753 ft, for a total one-way distance of about six miles.

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.

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.