The Taos Plateau volcanic field is an area of extensive

volcanism Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a he ...

Taos County, New Mexico Taos County is a county in the U.S. state of New Mexico. As of the 2020 census, the population was 34,489. Its county seat is Taos. The county was formed in 1852 as one of the original nine counties in New Mexico Territory. Taos County com ...

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. It is the largest volcanic field in 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 Chihuah ...

, spreading over . The total erupted volume is estimated at . The age of most of the vents and associated

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

s in the field is estimated to be between 1.8 and 4 million years, with a few 22-million-year-old vents. The composition of the lavas varies from tholeiitic

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...

. Landforms include sheet flows,

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

s, and

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava ...

es. The sheet flows of the Servilleta Basalt are well-exposed in the Rio Grande Gorge carved by the

Rio Grande The Rio Grande ( or ) in the United States or the Río Bravo (del Norte) in Mexico (), also known as Tó Ba'áadi in Navajo language, Navajo, is one of the principal rivers (along with the Colorado River) in the Southwestern United States a ...

. The highest point of the field is San Antonio Mountain at .

Notable vents

The field contains at least 35 vents, arranged in a rough concentric pattern across. The central part of the field is the most

mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...

, consisting of

tholeiitic basalt The tholeiitic magma series () is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic ...

es, with

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 predomina ...

vents further out and

rhyodacite Rhyodacite is a volcanic rock intermediate in composition between dacite and rhyolite. It is the extrusive equivalent of those plutonic rocks that are intermediate in composition between monzogranite and granodiorite. Rhyodacites form from rapid ...

vents in the outer part of the field. Two small

domes in the center of the field are exceptions to this pattern.

Origin

The field lies near the intersection of the

Jemez Lineament The Jemez Lineament is a chain of late Cenozoic volcanic fields, long, reaching from the Springerville and White Mountains volcanic fields in East-Central Arizona to the Raton-Clayton volcanic field in Northeastern New Mexico. The lineament w ...

with the Rio Grande rift. Here hot mantle rock has bulged upwards into the rift, allowing a high degree of decompressional melting to produce the tholeiitic magmas. The outer zone of andesites and rhyodacites is interpreted as a lower degree of melting, while the two rhyolite domes are interpreted as resulting from

fractional crystallization Fractional crystallization may refer to: * Fractional crystallization (chemistry), a process to separate different solutes from a solution * Fractional crystallization (geology) Fractional crystallization, or crystal fractionation, is one of the ...

of magma in the shallow crust.

Economic resources

Perlite Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the Hydrate, hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an indu ...

is mined from the rhyolite flows and domes at No Agua. The production here has contributed to making New Mexico the leading producer of perlite in the United States.

References

External links

Documentary: Sleeping Monsters, Sacred Fires: Volcanos Of New Mexico
* Volcanic fields of New Mexico Landforms of Taos County, New Mexico Miocene volcanoes Pliocene volcanoes Pleistocene volcanoes Rift volcanoes Neogene geology of New Mexico Quaternary New Mexico Miocene United States Pliocene United States Pleistocene United States Basin and Range Province {{NewMexico-geo-stub

Notable vents

Origin

Economic resources

See also

References

Further reading

External links