San Antonio Mountain is a free-standing volcanic peak in

Rio Arriba County, New Mexico Rio Arriba County is a county in the U.S. state of New Mexico. As of the 2010 census, the population was 40,246. Its county seat is Tierra Amarilla. Its northern border is the Colorado state line. Rio Arriba County comprises the Española, N ...

. With an elevation of 10,908 feet, San Antonio Mountain is the highest peak within the Taos Plateau volcanic field, the largest volcanic field within the

Rio Grande Rift The Rio Grande rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. The rift extends from central Colorado in the north to the state of Chihuahu ...

valley. The mountain lies just outside a northwest boundary of the Rio Grande del Norte National Monument. It lies within the Carson National Forest and is administered by the U.S. Forest Service rather than the Bureau of Land Management. It is called "Bear Mountain" by

Tewa The Tewa are a linguistic group of Pueblo Native Americans who speak the Tewa language and share the Pueblo culture. Their homelands are on or near the Rio Grande in New Mexico north of Santa Fe. They comprise the following communities: * ...

-speaking peoples in the Rio Grande valley, and is known as the mountain of the north in their

cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

Geography

San Antonio Mountain is one of several volcanic peaks within the 7000 square kilometer Taos Plateau volcanic field, a region of volcanic activity within the

Rio Grande rift The Rio Grande rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. The rift extends from central Colorado in the north to the state of Chihuahu ...

valley. Other nearby peaks include

Ute Mountain Ute Mountain, also known as Ute Peak or Sleeping Ute Mountain (; Ute: ''Wisuv Káruv'', Navajo: ''Dził Naajiní''), is a peak within the Ute Mountains, a small mountain range in the southwestern corner of Colorado. It is on the northern edge o ...

(10,082 feet), Cerro de la Olla (9,475 feet), Cerro del Aire (9,023 feet), and Cerro Montoso (8,655 feet). San Antonio Mountain is both the highest peak in the region and possesses the greatest

relief Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term '' relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that th ...

, but it is shorter than the highest peaks in the surrounding ranges: Grouse Mesa (11,403 feet) in the Tusas Mountains to the west, and Wheeler Peak (13,161 feet) in the Sangre de Cristo Mountains to the east. However, because it stands alone, San Antonio Mountain is a distinctive feature that can be seen from as far as 60 or more miles away in southern Colorado and northern New Mexico. San Antonio Mountain has a base diameter of five miles, and rises dramatically from the surrounding

sagebrush Sagebrush is the common name of several woody and herbaceous species of plants in the genus '' Artemisia''. The best known sagebrush is the shrub '' Artemisia tridentata''. Sagebrushes are native to the North American west. Following is an al ...

plains of the lower San Luis Valley. Forest Road 418 goes to the top, where there are radio and television towers. However it may not be open to motorized travel by the general public, as there is a locked gate where the road crosses private property. Hikers may walk around the private property.

Geology

The mountain is a

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite ...

dome, built up of

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

high in

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...

and mildly elevated in

alkali metal oxide The alkali metals react with oxygen to form several different compounds: suboxides, oxides, peroxides, sesquioxides, superoxides, and ozonides. They all react violently with water. Alkali metal suboxides * Hexarubidium monoxide (Rb6O) h * No ...

s that erupted between 3.36 and 2.9 million years ago. Most of the mountain consists of dacite flows up to thick. These are glassy at their bases, massive and grey in their center sections, and blocky on the upper surfaces. These are sometimes oxidized to a red color. The mountain has north and south summits separated by a shallow saddle, with

cinder Cinder is an alternate term for scoria. Cinder or Cinders may also refer to: In computing *Cinder (programming library), a C++ programming library for visualization *Cinder, OpenStack's block storage component * Cyber Insider Threat, CINDER, a ...

and spatter around the southern summit that shows this was the youngest vent area. The mountain almost buries a slightly older and much smaller

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predo ...

cone to the northwest.

Flora and fauna

The mountain features

Gambel oak ''Quercus gambelii'', with the common name Gambel oak, is a deciduous small tree or large shrub that is widespread in the foothills and lower mountains of western North America. It is also regionally called scrub oak, oak brush, and white oak. ...

and

ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...

, with Douglas fir, Engelmann spruce, and quaking aspens at higher elevations. San Antonio Mountain is an important winter habitat for migrating herds of elk, and hosts one of the largest populations of elk in New Mexico, estimated at 7,000 individuals. The mountain and its surroundings also provide habitat for

pronghorn The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American a ...

, golden eagle, hawks, bears, mountain lions, mule deer and white-tailed jackrabbits among other smaller mammals. In the fall, the Stuart Meadows wetlands on the nearby Rio San Antonio provide a stopover for migrating Sandhill cranes, mallards, American wigeon, Northern pintail, common yellowthroat, and sora.

References

External links

* {{Mountains of New Mexico Volcanoes of New Mexico Mountains of Rio Arriba County, New Mexico Carson National Forest