VOLCANO TYPES o f N e w M e x i c o
Volcano
Type
Simple
Drawing/Section
New Mexico
Example
How and Why It Erupts
• violent explosive and catastrophic eruption of glowing clouds of ash that flow away
from the caldera (ash-flows or pyroclastic flows), due to very high gas content and very
high silica magma in a very large magma chamber
caldera
• the roof of the extremely large, shallow magma chamber collapses during and after
eruption
(super volcano)
Valles Caldera
• uplift (rebound) of the caldera floor over a long period of time to form Redondo Peak,
and even later eruptions of high silica, low gas content lava domes around the interior
margin of the caldera
• lava intrudes earlier lava and piles up at the vent because very high silica magma
makes the lava viscous
dome
• mostly non-explosive eruptions due to low gas content magma
• near-surface intrusions are formed when continued eruptions push into the pile
Cerro La Jara, Valles Caldera, Jemez Mtns
• many intermittent eruptions of different types over a long time period caused by
changes in the magma composition
composite
• built by lava flows, ash, and domes from multiple conduits of intermediate to low
viscosity due to medium to low silica and gas content magma
Mount Taylor volcano
cinder
• intermittent mudflows and landslides are interlayered with ash, lava flows. and broken
rocks due to crumbly materials erupted on steep upper slopes
• single to multiple eruptions that extend over years to decades
• moderately explosive eruptions of mafic (basaltic) composition, including lava flows,
due to moderate gas content and low silica magma
(scoria)
cone
Cat Hills, Los Lunas
• builds a small volcano of ash, cinder, and scoria (fragmented magma) that is
commonly 0.6 to 1.2 miles (1-2 km) in diameter
• multiple eruptions of long lava flows from a central conduit over a moderately long
time period
shield
• mostly non-explosive and fluid eruptions, due to low silica and low gas content magma
• forms a low, broad volcano with some ash and cinder at the summit
Cerro Verde volcano
lav a
flow
• single eruption of a long, fluid, large volume of mafic (basaltic) lava
• mainly lava with little ash and cinder due to low gas
• lava covers large area due to low viscosity and low silica magma
• usually erupted in association with a small cinder cone source volcano
McCartys lava flow, El Malpais
• multiple violent steam-blast eruptions, due to the interaction of magma and
groundwater or surface water
maar
• forms a crater with its floor below ground level that is surrounded by a low rim of ejecta
composed of fragmented magma and surrounding rock
Zuni Salt Lake crater
volcanic
neck
• the near-surface interior of a small volcano that has experienced erosion of its exterior
flanks
• erosion leaves behind the hard crater fill (lava flows, ash, and cinder) and the
near-surface, magma-filled throat or conduit of the original volcano
Cabezon Peak, Rio Puerco
volcanic neck
• a large region over which volcanism is active over a time period from thousands to
millions of years
field of
small cones
• many new eruptions from multiple conduits, rather than many eruptions from a single
volcanic vent, due to small batches of magma that are generated and erupted from
different places within the region over time to form each individual volcano
(volcanic field)
Raton-Clayton volcanic field
• consists of a concentration of varied types of small volcanoes, dominantly cinder
cones and their associated lava flows, but also some shield volcanoes and lava domes
Poster design, graphic, and photographs by L.S. Crumpler and Jayne Aubele. These are just a few of New Mexico’s volcanoes.
For more information about the location of volcanoes in New Mexico go to poster no. 2, or go to “Volcanoes of New Mexico” at
www.nmnaturalhistory.org/sci_volcanoes.html
New Mexico Museum of Natural History and Science
Imagenés de la historia natural, No. 3