Geologic Tour of New Mexico

Bluewater Lake State Park lies at an elevation of 7,400 ft in Las Tuces Valley near the Continental Divide in the Zuni Mountains. The park is between Gallup and Grants along I–40, 7 mi southwest of Prewitt via NM-412. A forest of cottonwoods, piñon, and juniper surrounds the lake. The Navajos knew the area as “large cottonwood trees where water flows out” (Julyan, 1996). It became a state park in 1955. Bluewater and Cottonwood (Azul) Creeks feed the lake. The lake itself is formed by an arched dam 90 ft high and 500 ft long (Robinson, 1994) that impounds 38,500 acre-ft of water. The last time water spilled over the dam was in 1941. The dam is convex in the upstream direction for increased strength, and it is at the mouth of Bluewater Creek in a steep-walled canyon. An overlook at the end of the road through the park facilities offers an excellent view of the dam and canyon. A primitive hiking trail leads down into the canyon below the dam.

The New Mexico Department of Game and Fish maintains a permanent pool of water for fish and periodically stocks the lake with rainbow trout and channel catfish. Indeed, the lake is blue, as the name implies. It is well known to ice-fishermen during the winter. Power and sail boating, hiking, water skiing, wind surfing, and swimming are possible recreational activities in addition to fishing, camping, picnicking. Care should be taken driving in wet weather along the north side of the lake because of muddy conditions. Not all 25 mi of shoreline belong to the state park; some land surrounding the lake belongs to private individuals, Indian tribes, and U.S. National Forest. All water, however, is open to the public.

Kilbourne Hole in south-central New Mexico is a classic example of a maar crater that formed as a result of the explosive interaction of hot basaltic magma with groundwater during a volcanic eruption. When the steam-saturated eruption column that forms during an explosive event gravitationally collapses, a ring-shaped surge travels radially outward along the ground away from the vent. The stratified, cross-bedded pyroclastic surge deposits around the crater at Kilbourne Hole are spectacular. The surge deposits may have formed as a consequence of a series of steam explosions during the emplacement of the basalt.

Kilbourne Hole is unique because of the remarkable abundance of both crustal and mantle (peridotite/olivine-bearing) xenoliths that are in basalt bombs ejected during the eruption. Xenoliths are inclusions of pre-existing rock derived from country rocks, in this case, pieces of mantle and crust, that were incorporated into the mafic magma as it moved from a depth of about 40 miles (60 km) to the surface.

Monument Rock is located west of Socorro and north of U.S. Highway 60 in the eastern Sawtooth Mountains of Catron County, New Mexico. The area can be reached from Datil by traveling west along Highway 60, 12.3 miles to Forest Road 6A. Turn right on Forest Road 6A and drive north 3.7 miles to the prominent spire of Monument Rock.

The area can also be accessed from Pie Town by driving east along U.S. Highway 60 to Forest Road 316. Turn left onto Forest Road 316 and drive northeast 3.5 miles to Forest Road 6A. Turn left and drive 1.1 miles to Monument Rock.

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.

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.

Pancho Villa State Park in Columbus, New Mexico, was established in 1959 “in interest of preservation of the memory of the unique, historical occasion of the last hostile action by foreign troops within the continental United States”. It became the only park in the United States to be named after a foreign invader. The creation of the 60-acre park was a gesture of good will between the United States and Mexico. The town of Columbus has been designated a National Historic Site. Across the street from the park is the privately owned Pancho Villa Museum.

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.

Carlsbad Caverns National Park (CCNP) is located in southeastern New Mexico about 20 miles south of Carlsbad. It was initially designated a national monument in 1923, was elevated to a national park in 1930, and was recognized by United Nations Educational, Scientific and Cultural Organization as a World Heritage Site in 1995. Its 46,766 acres include 120 known caves, the two largest of which are Carlsbad Cavern and Lechuguilla Cave, with total passage lengths of 32 miles and 143 miles, respectively, which places them among the world’s longest. Lechuguilla (open only to experienced researchers) is the second deepest limestone cave in the United States at 1,604 feet. More importantly than cave size is the great variety and beauty of the formations and the complexity of the processes that formed them.

Morphy Lake State Park offers fishermen, campers, hikers, and other visitors a rustic alpine setting in the Sangre de Cristo Mountains. Spectacular views are the result of complex geologic processes active since Proterozoic time (1,700 m.y. ago): two major periods of mountain building (called orogenies) and most recently erosion and sedimentation by glaciers and rivers.The state park is 7 miles southwest of Mora and 3 miles northwest of Ledoux in the eastern Sangre de Cristo Mountains in northern New Mexico. It is the least accessible of the New Mexico state parks.

Fort Union was established in 1851 to provide a much-needed military presence to travelers on the Santa Fe Trail. The trail had been active since 1821, when much of what is now New Mexico became U.S. territory in 1848, at the end of the Mexican War. Fort Union’s spectacular location on the western edge of the Great Plains was a strategic one, sited as it was near the junction of the Mountain Branch of the Santa Fe Trail with the Cimarron Cutoff. Between 1851 and 1891 Fort Union contained the largest American military presence in the Southwest; over 1,600 troops were stationed there in 1861. In 1878 the railroad came to New Mexico over Raton Pass, and by 1891 Fort Union had been abandoned. Visitors to the national monument can see some impressive historic ruins, including the foundations and adobe walls of many of the original buildings, and remnants of the deeply-rutted Santa Fe Trail.