Natural World

Natural Features & Ecosystems

Capulin Volcano National Monument preserves approximately 800 acres (324hectares) primarily the cinder cone volcano. More than 15 square miles (~39 km2) of associated lava flows are outside the monument boundaries. The volcano has been well-preserved with the greatest erosion being limited to where the cone is cut by a 2-mile road that spirals its way to the crater rim. The volcano rises to a height of 8182 feet (2495 m) above sea level, or 1300 feet (396 m) above the surrounding High Plains and at its base is 4 miles (6.4 km) in circumference. The crater is 415 feet (126 m) deep and 1450 feet (442 m) in diameter. The slopes of the volcano have been partially stabilized by the formation of soils, produced by the breakdown of the volcanic material by lichens and mosses. Once these soils formed, grasses, wildflowers, shrubs and trees took root. Chokecherry trees, which are common along the crater trails, inspired the name for this cinder cone volcano; Capulín is a Mexican-Spanish word for Chokecherry.

The monument lies in the Raton section of the Great Plains (or Interior Plains) physiographic province—an immense sweep of country that stretches north from Mexico to Canada, and east from the Rocky Mountains. This section of the Great Plains is characterized by volcanism. Capulin Volcano is just one out of many volcanoes in northeastern New Mexico. This collection of volcanoes, called the Raton-Clayton volcanic field (RCVF), is the easternmost Cenozoic—66.4 million years ago (Ma) to present—volcanic field in the United States. The RCVF covers nearly 8000 square miles, from Trinidad, Colorado to Clayton, New Mexico, and has been active during the last 9 million years. The eruption of Capulin volcano, ~ 60,000 years ago, is one of the most recent eruptions in the field. The field is presently dormant with no activity in the last 30,000 or 40,000 years. Individual volcanic centers within the field, such as Capulin Volcano, are considered extinct.

Exotic Species

While the prairie surrounding Capulin is grazed by cattle, the prairie and grasslands within the monument are preserved in their native state. Unfortunately, interspersed among the native grasses are several nonnative plant species that disrupt the ecological integrity of the mixed-grass prairie. Common Mullein, Houndstongue, Hoary Cress, Cheatgrass and Russian Thistle are just some examples of invasive nonnative plants that are competing with the native species. The monument, through its resource management efforts, renders aid to the native prairie plants and actively discourages the invasive exotics.

Nature & Science

Capulin Volcano National Monument, a well-preserved, relatively young (58,000 to 62,000 years old), symmetrical cinder cone, is one of the outstanding landmarks located in the northeast corner of New Mexico. It rises steeply from the surrounding grassland plains to an elevation of 8,182 feet above sea level, providing unobstructed, panoramic views of the volcanic field and distant snow-capped mountains. The irregular rim of the crater is about a mile in circumference and the crater about 400 feet deep.

Capulin Volcano also offers visitors excellent opportunities for observing and understanding volcanic formation. The large volcanic field surrounding the monument contains at least 100 recognizable volcanic features and provides visitors with insights into 10 million years of the geological history of Northern New Mexico.

Plants

Capulin Volcano National Monument lies within the transition from the high elevations of the Rocky Mountains to the sweeping grasslands of the Great Plains. The slopes of the volcano are primarily pinyon/juniper woodlands and the lower plains are shortgrass and mixed grass prairie.

Species lists and information are available on the forest and prairie ecosystem pages.

Prairie

Capulin Volcano National Monument lies within a transition zone, from the high elevations of the Rocky Mountains to the sweeping grasslands of the Great Plains. The prevailing wind direction in this region is westerly; therefore once precipitation reaches the grasslands, there is generally only enough water to support short- (less than 2 feet, or 0.6 am) and midsize (2-4 feet, or 0.6-0.8 am) grasses. However, as the winds travel toward Capulin, they pick up more moisture and as a result deliver enough precipitation to support a few tall grass (over 5 feet, or 1.5 am) species.

Within the monument, shortgrass prairie is dominant, with medium-sized grasses, and the three main species of tall grasses—Big Bluestem, Indiangrass, and Switchgrass—also being present. Blue grama and Sideoats grama are two dominant grasses that thrive in the monument.

Desert plants, such as cacti and yuccas, also live on the short-grass prairie within the monument.

Abundant wildflowers, such as Prickly Poppy, Indian Paintbrush, Sunflowers, and Beardlip Penstemon, are found throughout the monument.

 

 

Forest

The forested slopes of Capulin Volcano are covered in pinyon pine/juniper woodland. This short-statured forest is dominated by pinyon pine, juniper, sumac, wavyleaf oak, Gambel’s oak, and mountain mahogany.

Some ponderosa pines are found in the monument. These large pines usually occur in mountains in pure stands. They are more solitary and mixed through the other woodlands in the lower elevations of Capulin Volcano.

 

Mammals

Large mammals such as deer and bear will travel through the park, using areas for food and shelter. Because the park is small and contains no permanent water source, large animals must travel over great distances to survive. Deer and Elk grow antlers which are shed and regrown each year. Depending upon age and nutrition, antlers can have many branches and grow to spectacular size.
Pronghorn, sheep, goats, and bison grow true horns. These are bony outgrowths of the frontal bone. Horns are not branched, do not shed, and continue to grow throughout the animal's lifetime. Pronghorn do shed the sheath (made of keratin like your fingernails) on their horns each year. Tracks, scat, and other evidence indicate the presence of a variety of other mammals. Scat on trails is often that of coyote, fox or bobcat. Trees have been stripped of bark by porcupines. Mice and gopher leave piles of dirt behind as they burrow. Pine cones chewed and stripped of seeds feed the rock squirrels and least chipmunks. Full wildlife surveys have not been conducted in the park in recent years. A checklist of mammals from 1973 and a partial survey by the New Mexico Natural Heritage Program done in 2002 are the most current information we have available.

Animals

The high plains of northeastern New Mexico, including Capulin Volcano, are where shortgrass prairie and mountain forest meet. This transition between two ecosystems provides habitat for many different plants and animals.

Large mammals such as deer and bear roam the volcano. The combination of grassland and forest provides habitat for upland and woodland songbirds. Insects swarm at the high elevations and reptiles find homes in the rocky crevices.

Birds

Reptiles and Amphibians

Reptiles and amphibians are cold-blooded animals whose bodies take on the temperature of their surroundings. They may be seen basking in the sun on warm rocks that make up the mountain. Cool nights usually send them into burrows or crevices to keep warm.

Several species of snakes and lizards inhabit the monument. Amphibians are somewhat less numerous since there is no permanent water source in the park. Complete wildlife surveys have not been done in the park.

Insects

Capulin Volcano supports a wide variety of insects and particularly large populations of some that migrate to high elevations. However, mosquitos are not a problem here, most likely because the volcano lacks permanent water sources for breeding sites.

Complete invertebrate surveys have not yet been conducted in the park, but lists are available for Union County, NM. False Cinch Bugs- False Cinch bugs are less than 1/4 inch (1/2 cm) long, brownish gray, narrow bodied true bugs. While immature, they have inconspicuous red markings on their body. They feed on plants of the mustard family. As they reach maturity, they begin to cluster together in extremely high numbers in preparation for migration. They are a temporary nuisance but do little or no feeding while clustered. Wet winters result in greater mustard populations which will lead to larger populations of False Cinch Bugs.

These bugs are numerous at the top of the volcano. They are particularly attracted to light colors, especially white. While annoying, they do not bite.

Raton-Clayton Volcanic Field

The cinder cone we know as Capulin Volcano serves as the centerpiece for an amazing display of volcanic features in and around the national monument. It shares the landscape with hundreds of other cinder cones and basaltic lava flows, rhyolitic volcanic domes and a large andesitic shield volcano. This volcanic field includes lavas of wide chemical range: from rhyolite (> 68 weight % SiO2), to dacite (63-68 wt % SiO2), to basalt (< 52 wt % SiO2), as well as varieties of these end-member compositions.

Beginning in the Cretaceous Period, about 146 to 65 million years ago (Ma), prior to the volcanic eruptions in the area that would become northeastern New Mexico, this region was covered by an interior seaway that initially connected the Arctic Ocean and the Gulf of Mexico. This seaway expanded and contracted throughout the Cretaceous. When it expanded, dark-colored, fine-grained marine sediments were deposited, such as the Pierre Shale, which can be seen in outcrop along Interstate 25 between Las Vegas and Raton.

When the seaway contracted, beach, river, and delta deposits covered the marine sediments. As the Rocky Mountain Range began to rise, this seaway retreated forever. Beginning about 9 million years ago, in the western region that is bounded today by the New Mexico towns of Raton and Clayton, called the Raton-Clayton Volcanic Field (RCVF), large volumes of lava were erupted onto either the Ogallala Formation (Miocene age) or the Poison Canyon Formation (Paleocene age). The Ogallala Formation was formed from the deposition of sediment carried by rivers from the Sangre de Cristo Mountains, and today serves as a major source of groundwater for much of the Great Plains. These lavas also erupted on the northern and southern perimeters of the RCVF. Chemically the majority of the lavas erupted during this time are classified as either olivine basalts or alkali basalts. Another type of lava erupted here is the Red Mountain rhyodacite, which erupted between 6.8 and 6.3 Ma; this lava comprises Red Mountain, a rhyolitic volcanic dome, on Johnson Mesa. These lavas are grouped together in what is referred to as the "Raton Phase" of RCVF activity. The next phase of volcanic activity began approximately 3.0 Ma at Rabbit Ears, which today is an eroded vent near Clayton, New Mexico. This stage of volcanism is referred to as the "Clayton Phase" as the majority of lavas erupted during this time are found between Clayton and Sierra Grande; although, Jose Butte and Robinson Peak are located west of Capulin. The Clayton lavas typically have very low SiO2 content (42-45 wt %) and are classified as nephelinite and basanite. The Capulin Phase lavas were also erupted onto the Ogallala Formation, as well as onto the light-brown sandstone called the Dakota Sandstone (Cretaceous Age), which locally crops out near the towns of Folsom and Des Moines. Presently, there is no evidence to suggest that the volcanism in this phase has ended, and it may only be in an eruptive hiatus. However, since the last known eruption occurred more than 30,000 years ago, the RCVF is considered dormant.

Volcanic Field Features

The processes that created Capulin Volcano also created extraordinary forms around its base. The lava flows formed a resistant cap on the easily weathered sedimentary rocks, which protected this underlying rock from erosion while all the surrounding rock washed away. The result is the high, flat-topped mesas, such as Raton Mesa, Mesa de Maya, and Johnson Mesa.

At Capulin Volcano moving lava developed a crust on the surface as it cooled and in places this surface was “wrinkled” by the flowing lava beneath producing pressure ridges.

Lava cascades and levees formed as the lava flowed, while caves and lava tubes formed beneath the crust as the lava drained away. These lava tubes and caves are quite fragile, and so no intact lava tubes or caves may be found in the park today.

Partially cooled lava, pushing through cracks like toothpaste from a tube, solidified into semi-rounded squeeze-ups called tumuli.

Environmental Factors

Erosion, fire, and non-native species play an important part in shaping the monument landscape.  

Erosion on the volcano is primarily associated with the road which circles the mountain to the crater rim. Culverts under the road provide narrow paths for water run off which create erosion channels and gullies down the sides of the mountain. Heavy rain and high winds also regularly shift the ash and cinders which built the mountain.

Capulin Volcano National Monument was set aside from public use in 1891 and was designated a National Monument in 1916. Fire was considered destructive and dangerous. All fires were suppressed and the natural fire cycle of both grasslands and woodlands disrupted.

Until recently, the Monument has not experienced any form of fire management. The first prescribed fire was conducted in April, 2005. This prescribed burn, as well as others conducted in the future, will help restore a natural fire cycle to the monument ecosystems. It will also lessen the possibility for devastating wildfires, which could result from a build-up of fuel sources within the Monument.

Nonnative or exotic species are those that evolved elsewhere and have been transported and purposefully or accidentally disseminated by humans. These species “disrupt the functioning of native ecosystems” and become problematic by rapidly dispersing into communities in which they have not evolved, and by displacing native species because of evolutionary mismatches. Eventually the introduced species may dominate an ecosystem, thereby making conditions impossible for the native species to exist. At Capulin Volcano, there are several exotic species of plants present.

Geology

Between 58,000 to 62,000 years ago, just yesterday on the clock of geologic time, the scene near Capulin would have been one of fire, ash, glowing lava, and ear-shattering explosions.

Capulin Volcano formed during the most recent period of activity in the Raton-Clayton Volcanic Field. The cone rises more than 1,000 feet above the plains to 8,182 feet above sea level and consists chiefly of loose cinders, ash, and other rock debris. These materials were ejected during successive eruptions and fell back upon the vent, piling up to form the conical mountain. The symmetry of Capulin Volcano was preserved because lava did not flow from the main crater but from secondary vents located at the western base of the cone.

Evidence of the other episodes of activity can be seen in nearly 100 nearby volcanic peaks and lava capped mesas. The largest of these volcanic peaks is the Sierra Grande, an extinct volcano rising some 2,200 feet above the surrounding plain, about 10 miles to the southeast. The largest lava flow is Johnson Mesa, 14 miles long and 7 miles wide, to the west of Capulin.