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NPS Geodiversity Atlas—Capulin Volcano National Monument, New Mexico

Geodiversity refers to the full variety of natural geologic (rocks, minerals, sediments, fossils, landforms, and physical processes) and soil resources and processes that occur in the park. A product of the Geologic Resources Inventory, the NPS Geodiversity Atlas delivers information in support of education, Geoconservation, and integrated management of living (biotic) and non-living (abiotic) components of the ecosystem.

capulin volcano gri report cover with image of cone
In-depth geologic information is contained in the baseline inventory products of the Geologic Resources Inventory, see table below.

Geologic Features and Processes

Capulin Volcano is one of the tallest and most perfectly formed cinder cones in North America. The volcano stands 2,494 m (8,182 ft) above sea level and nearly 400 m (1,300 ft) above the surrounding plain. It is the primary geologic feature at Capulin Volcano National Monument and a fundamental resource and value of the monument (National Park Service 2014c).

Capulin Volcano lies near the center of the 20,000 km2 (8,000 mi2 ) Raton-Clayton volcanic field, which extends for more than 130 km (80 mi) between the cities of Raton and Clayton from which the field received its name.

The eruption of Capulin Volcano occurred about 55,000 years ago (Pleistocene Epoch) toward the end of the most recent phase of volcanism in the RatonClayton volcanic field. Hills, peaks, and other features both younger and older than Capulin Volcano formed as a result of regional volcanic activity. These features can be seen from the Crater Rim Trail. The largest of these features is Sierra Grande, an extinct volcano rising 670 m (2,200 ft) above the surrounding plain to the southeast of Capulin Volcano. To the northwest, mesas such as Johnson Mesa are capped with some of the oldest lava in the field.

Geologic features and processes at Capulin Volcano National Monument include the following:

  • Capulin Basalt. Capulin Volcano National Monument and the surrounding area are composed entirely of a single, formally named map unit— Capulin Basalt. Analysis of rock samples from Capulin Volcano and nearby Baby Capulin, a cinder cone outside the monument, found that the rock is technically a “trachybasalt,” having more abundant alkali elements, such as sodium and potassium, than true basalt. The presence of Dakota Sandstone xenoliths (foreign rock fragments) and xenocrysts (foreign crystals) is a characteristic feature of Capulin Basalt. Silica from Dakota Sandstone quartz grains is a factor in the relatively high amount of silica (50%–55%) in Capulin Basalt.
  • Raton-Clayton Volcanic Field. Capulin Volcano National Monument is part of the 20,000-km2 (8,000-mi2 ) Raton-Clayton volcanic field, which has been active episodically for the past 9 million years in three phases: (1) Raton phase, which had two distinct episodes (9.0 million–7.3 million years ago and 5.6–3.5 million years ago); (2) Clayton phase (3.0 million–2.2 million years ago); and (3) Capulin phase (1.69 million–32,000 years ago). Capulin Volcano erupted during the Capulin phase. The volcanic field consists of an estimated 125 vents and is characterized by a low volumetric eruption rate and inverted topography
  • Capulin Volcano. Not only is Capulin Volcano a type example of a cinder cone, it is archetypal— bigger and more perfectly formed than most cinder cones. The beauty of this volcano is the reason for its inclusion in the National Park System.
  • Volcanic Features. Richman (2010)—the source for the GRI GIS data set—mapped Capulin Volcano and the complex boca, delineating two boca ramparts, 16 lava cascades, 19 lava lakes, 15 lava levees, 18 lava ridges, one pooled lava flow, one push-up, two rafted cinder cones, 24 spatter deposits, one spatter flow, 23 squeeze-ups, 18 tumuli, and seven vents.
  • Age of Capulin Volcano. Once considered less than 10,000 years old, Capulin Volcano is now known to have formed 55,000 ± 2,000 years ago.
  • View from Capulin Volcano. The view from the crater rim is probably what led Homer Farr, the custodian of Capulin Mountain National Monument (former name of the monument) from 1923 to 1955, to build a road to the summit. The “dramatic view” is one of four statements of significance identified in the monument’s general management plan; the other three are the classic cinder cone, occurrence in the geologically diverse Raton-Clayton volcanic field, and the cinder cone’s accessibility.
  • Playa Lakes. Playa lakes—ephemeral lakes in arid or semiarid regions that appear in the wet season and subsequently dry up—are one of the only nonvolcanic features in the viewshed of Capulin Volcano National Monument. Playa lakes are visible to the south and east of Capulin Volcano.
  • Aeolian Features. A notable aeolian (windblown) feature at Capulin Volcano National Monument is the asymmetrical crater rim, which is higher on the northeastern side. At the time of cone building, prevailing southwesterly winds caused more cinders to accumulate on the opposite (northeastern) side of the volcano. Loess (windblown dust) is another aeolian feature at the monument. This material fills vesicles and cracks on lava flows. Loess-infilling serves as an informal dating method of lava flows and associated landscapes. Loess also plays a role in soil formation.
  • K-T Boundary. Although Capulin Volcano National Monument does not contain the Cretaceous-Tertiary (“K-T”) boundary, the nearby exposure at Goat Hill may be of interest to visitors. This boundary marks a massive, worldwide extinction of an estimated 50% of all species, including dinosaurs, 66 million years ago.

Also see the park Geologic Resources Inventory Report for details on these and other volcanic features and process, as well as a discussion of resource management issues.

Geology Field Notes

Students and teachers of college-level (or AP) introductory geology or earth science teaching courses will find that each park's Geologic Resource Inventory report includes the Geologic History, Geologic Setting, and Geologic Features & Processes for the park which provides a useful summary of their overall geologic story. See Baseline Inventories, below.

Regional Geology

Capulin Volcano National Monument is a part of the Great Plains Physiographic Province and shares its geologic history and some characteristic geologic formations with a region that extends well beyond park boundaries.

Geologic Setting & Regional Geology

The Raton-Clayton Volcanic Field is in the Raton section of the Great Plains physiographic province. The Raton section has substantially more topographic relief than most of the rest of the Great Plains with mesas capped by resistant lava flows and volcanic edifices dominating the landscape. The volcanic rocks of the Raton-Clayton Volcanic Field are found at the surface in much of the Raton section, with Cretaceous or Cenozoic sedimentary rocks otherwise at the surface.

The Raton section extends from southern Colorado where the land surface gradually climbs in elevation from the Arkansas River to the lava-flow-capped mesas that characterize the northern and northwestern portion of the volcanic field. To the southwest, the Raton section includes the Ocate Volcanic Field near Wagon Mound, New Mexico and just north of Fort Union National Monument. The southern boundary of the Raton section is the Canadian escarpment along the Canadian River.

Raton-Clayton Volcanic Field

The Raton-Clayton Volcanic Field is the easternmost young volcanic field in North America. Volcanic fields are areas that are more or less covered by volcanic rocks. Many volcanic fields are clusters of cinder cones, sometimes with a composite cone in the middle of the field. The Raton-Clayton Volcanic Field consists of cinder cones, volcanic domes, and the large andesite shield volcano, Sierra Grande. It covers approximately 7,700 square miles in northeastern New Mexico and southeastern Colorado.

The Raton-Clayton Volcanic Field is located along the Jemez lineament, a southwest-to-northeast alignment of young volcanic centers across northern New Mexico. This alignment is not the result of a hot spot track, such as the one that created the Hawaiian Islands as there is no eruptive age progression along it. The Jemez lineament is a long-lived feature that likely resulted from an intraplate boundary in the lithosphere dating back to the Precambrian when the North American continent was being built via tectonic collisions of island chains with the larger landmass.

Two other national park sites in New Mexico with young volcanic rocks are also located along the Jemez Lineament. El Malpais National Monument features young basaltic lava flows erupted in the Zuni-Bandera Volcanic Field, and Bandelier National Monuments contains ash flow tuffs that were erupted from the Valles Caldera.

Most researchers have recognized three phases of activity in the Raton-Clayton Volcanic Field. The initial phase, generally called the Raton phase, took place between 9.2 and 3.5 million years ago when a variety of eruptive centers were active mostly in the western parts of the field, and on its northern and southern margins. The middle (Clayton) phase occurred between about 3.8 and 1.7 million years ago and took place in the eastern and central areas of the field. The most recent or Capulin phase has been active in the center of the field during the last 1.7 million years.

Raton phase volcanics consist of lava flows that were erupted into topographic lows, along with domes of “pasty” (viscous) lava. The lava flows that now hold up the mesas west of Capulin Volcano are classic examples of inverted topography. As erosion took place since the time of eruption, the previously low areas that were filled with lava became topographic highs because the volcanic rocks are more resistant to erosion than the surrounding sedimentary rocks.

Sierra Grande is the largest volcano in the Raton-Clayton Volcanic Field. This volcano stands prominently to the southeast of Capulin Volcano and rises approximately 2,200 feet above the plains. The eruptions that formed Sierra Grande took place between 3.8 and 2.8 million years ago. Sierra Grande is an unusual volcano in that it is shaped most like a shield volcano, but is made of a different type of volcanic rock (andesite) that is more “pasty” than lava flows that build more typical basaltic shield volcanoes like Kilauea in Hawaiian Volcanoes National Park.

Most of the volcanism during the Capulin phase has been located in the vicinity of Capulin Volcano. Mud Hill, located just north of Capulin Volcano, is one of the oldest volcanoes of the Capulin phase, with its eruption occurring about 1.7 million years ago. Baby Capulin, a small cinder north of Mud Hill, erupted more recently than Capulin Volcano at 44,800 years ago. The most recent eruptions in the Raton-Clayton Volcano Field took place northeast of Capulin Volcano at Twin Mountain 37,600 years ago and Purvine Hills 36,600 years ago, both located a few miles northeast of Capulin Volcano.

While there have been no eruptions in the past 36,000 years, the field’s eruption frequency along with its periods of inactivity between eruptions suggest that volcanic activity in the area has not ceased. It is likely that any future volcanism will occur at a new vent since cinder cones like Capulin Volcano are monogenetic, meaning that they typically are the product of a single eruptive episode. After a cinder cone’s eruption ends, its plumbing system, or conduit, is blocked by solidified magma.

Most volcanoes located in the Raton-Clayton Volcanic Field, including Capulin, erupted basalt or similar rock types that are low in silica, but a range of compositions are found in the field.

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Capulin Eruption

The eruption that led to the construction of Capulin Volcano began with eruption of a lava flow from a fissure or series of small vents. Cinders on top of this first lava flow provide evidence that it was erupted prior to the formation of the Capulin cinder cone.

The cone-building phase of the eruption was characterized by intermittent, discrete explosive bursts that ejected cinders a few hundred feet into the air in firework-like incandescent “rooster-tails” in a Strombolian eruption. The cone grew quickly in height early in the eruption, then more slowly as it enlarged. As the base of a cone grew, a larger volume of material was required for each measure of additional height.

The height of the eruption column decreased as the eruption waned, so that the cinders and volcanic bombs to be still molten when they landed on the rim of the crater. They welded together to form deposits called spatter.

The vents in the boca became active after the main cone-building phase had ended or nearly ended. The eruption style changed to Hawaiian with lower fire fountains, lava lakes, lava tubes and pahoehoe (ropy) lava. Lava flowed initially to the south, and then towards the north in the final stages of the eruption.

Geologic Features of Capulin Volcano

Capulin Volcano has a long reputation as one of the “most perfect specimens of extinct volcanoes in North America” as it was described in an 1890 letter to the Commissioner of the General Land Office that led to the withdrawal of Capulin from the lands available for settlement, entry, or disposition. This significance was echoed when the site was established as a national monument in 1916.

Cinder cones are the most common type of volcanoes on land, but few are as large or as symmetrical as Capulin Volcano, making Capulin an archetype of the form. Cinder cones (also known as scoria cones) are simple volcanic edifices that consist of deposits of scoria that fall down around the vent during moderately explosive eruptions of basaltic (low silica) magma. The slope of a cinder cone is determined by the angle of repose, which for ash and cinders is between 25 and 32°. Periodically during an eruption, the cinders piling up around the vent may exceed the angle of repose. When this happens, the cinders and ash avalanche down the sides of the cone and into the crater, and reestablish a slope equal to the angle of repose. These avalanches play an important role in forming the layers of cinders and ash that make up cinder cones.

The rim of the Capulin cone is higher on the east side than the west side. During the eruption, winds probably blew predominately from west to east and more material accumulated on the east flank. Additionally, eruptions from the boca on the west side of the cone may have undermined that side, lowering its height.

The crater has a bowl shape with a diameter of approximately 1450 feet and a maximum depth of 415 feet. The vent area for the cone-building eruption is located at the bottom of the crater but is plugged by solidified lava and covered by blocks produced during erosion. The spatter deposits on the rim and in the crater of the Capulin cone have slowed erosion, helping preserve the shape of volcano although its height has been slightly reduced.

The lava flow vent area, or boca, at the base of Capulin Volcano is complex, with a variety of features that were produced during the eruption. Collapsed lava tubes, lava lake deposits, and spatter deposits have been mapped in the boca, in addition to two sections of rafted cinder cone that formed when pieces of the cinder cone flank that were carried out by erupting lava as it emerged at the mountain’s base.

Four lava flows that cover 15.7 square miles were erupted at Capulin Volcano, but only small parts of them immediately adjacent to the cinder cone are within the park boundary.

Age of Capulin Volcano

Accurate measurements of the age of rocks erupted at Capulin Volcano were not available until the 1990s. Previously, a correlation of alluvium below a Capulin lava flow to the Folsom archeological site led to an estimation that Capulin Volcano erupted less than 10,000 before present, a value that was reported in the literature for decades.

Advances in dating techniques and application of a new technique in the mid-1990s led to a determination that the Capulin eruption occurred between 56,000 and 62,000 years ago, although the eruption itself probably only lasted a few years or less.

More recent refinements in the argon-argon dating technique have yielded a much more precise age determination for the eruption age of Capulin Volcano: 54,200 ±1,800 years before present.

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Paleontological Resources

No fossils have been found in Capulin Volcano NM, and fossils are not likely to be present.

The Folsom site, the type site for the Folsom tradition (Paleo-Indian), is located approximately 8 miles northwest of Capulin Volcano. The Folsom site was the first location to show that now-extinct Pleistocene mammals coexisted with humans in North America. The site has been dated at approximately 10,500 years before present.

All NPS fossil resources are protected under the Paleontological Resources Preservation Act of 2009 (Public Law 111-11, Title VI, Subtitle D; 16 U.S.C. §§ 470aaa - 470aaa-11).

Caves and Karst

Areas with basaltic lava flows and features such as the Capulin boca may contain collapsed lava tubes and other types of cave openings or overhangs. A number of collapsed lava tubes have been mapped in the Capulin boca, but no caves have been documented to date.

All NPS cave resources are protected under the Federal Cave Resources Protection Act of 1988 (FCRPA)(16 U.S.C. § 4301 et seq.).

Related link
https://www.nps.gov/subjects/caves/index.htm

Geohazards

Natural geologic processes continue to occur in and around Capulin Volcano on time scales ranging from seconds to years. Visitors should be cautious and alert to geohazards that may be present. Rock fall and slope movements along the flanks of the volcano may present a potential hazard, especially along the Volcano Road.

Because cinder cones typically only have one period of activity (e.g., they are monogenetic), potential volcanic hazards at Capulin Volcano NM itself are minimal. However, given the eruption interval and periods of interactivity of the Raton-Clayton Volcanic Field throughout its history, future eruptions may occur in the vicinity of the national monument. Relative to other types of volcanic activity, eruptions of basaltic magmas like what was erupted Capulin Volcano tend to be low explosively, although lava flows may cover large areas. The Raton-Clayton Volcanic Field is not monitored for volcanic activity as the most recent eruption occurred more than 36,000 years ago. Volcanic areas are considered active only if they have had eruptions within the last 10,000 years. However, precursors such as earthquakes, gas emissions and other signs of unrest usually occur before an eruption. For example, at Paricutin Volcano that erupted in central Mexico from 1953 to 1952 and that is considered a good modern analog for Capulin Volcano, earthquakes and subterranean noises were reported prior to the eruption.

Northeastern New Mexico has a relatively low seismic hazard. The USGS 2014 Seismic Hazard Map indicates that the Capulin area has a 2% chance that an earthquake peak ground acceleration of between 8 and 10 %g (percent of gravity) being exceeded in 50 years due to earthquakes. Peak ground acceleration between 8 and 10 %g is roughly equivalent to V to VI on the Modified Mercalli Intensity Scale. The expected number of damaging earthquake shaking in northeastern New Mexico in 10,000 years is between 2 and 4.

Related Links
USGS Earthquakes Hazard Program Information by Region-New Mexico
https://www.usgs.gov/natural-hazards/earthquake-hazards/science/information-region-new-mexico?

Geology Field Notes

Students and teachers of college-level (or AP) introductory geology or earth science teaching courses will find that each park's Geologic Resource Inventory report includes the Geologic History, Geologic Setting, and Geologic Features & Processes for the park which provides a useful summary of their overall geologic story. See Baseline Inventories, below.

Regional Geology

Capulin Volcano National Monument is a part of the Great Plains Physiographic Province and shares its geologic history and some characteristic geologic formations with a region that extends well beyond park boundaries.

Maps and Reports

Geologic Resources Inventory

The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks. The products listed below are currently available for this park, check back often for updates as many maps, reports, and posters are still in progress.
  • Scoping summaries are records of scoping meetings where NPS staff and local geologists determined the park’s geologic mapping plan and what content should be included in the report.
  • Digital geologic maps include files for viewing in GIS software, a guide to using the data, and a document with ancillary map information. Newer products also include data viewable in Google Earth and online map services.
  • Reports use the maps to discuss the park’s setting and significance, notable geologic features and processes, geologic resource management issues, and geologic history.
  • Posters are a static view of the GIS data in PDF format. Newer posters include aerial imagery or shaded relief and other park information. They are also included with the reports.
  • Projects list basic information about the program and all products available for a park.

Source: Data Store Saved Search 2767. To search for additional information, visit the Data Store.

Soil Resources inventory

NPS Soil Resources Inventory project has been completed for Capulin Volcano National Monument and can be found on the NPS Data Store.

Source: Data Store Saved Search 2749. To search for additional information, visit the Data Store.

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Capulin Volcano National Monument

National Park Service Geodiversity Atlas

The servicewide Geodiversity Atlas provides information on geoheritage and geodiversity resources and values within the National Park System. This information supports science-based geoconservation and interpretation in the NPS, as well as STEM education in schools, museums, and field camps. The NPS Geologic Resources Division and many parks work with National and International geoconservation communities to ensure that NPS abiotic resources are managed using the highest standards and best practices available.

For more information on the NPS Geodiversity Atlas, contact us.

Part of a series of articles titled National Park Service Geodiversity Atlas.

Capulin Volcano National Monument

Last updated: July 23, 2021