Nazko Cone is a small potentially active

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 ...

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 ...

in central

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, located 75 km west of Quesnel and 150 kilometers southwest of Prince George. It is considered the easternmost volcano in the Anahim Volcanic Belt. The small

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

-covered cone rises 120 m above the Chilcotin-

Nechako Plateau The Nechako Plateau is the northernmost subdivision of the Interior Plateau, one of the main geographic regions of the Canadian province of British Columbia. It spans the basin of the Nechako River and its tributaries the Stuart River and Enda ...

and rests on glacial

till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

. It was formed in three episodes of activity, the first of which took place during the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

interglacial stage about 340,000 years ago. The second stage produced a large

hyaloclastite Hyaloclastite is a volcanoclastic accumulation or breccia consisting of glass (from the Greek ''hyalus'') fragments (clasts) formed by quench fragmentation of lava flow surfaces during submarine or subglacial extrusion. It occurs as thin marg ...

scoria Scoria or cinder is a pyroclastic, highly vesicular, dark-colored volcanic rock formed by ejection from a volcano as a molten blob and cooled in the air to form discrete grains called clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackso ...

mound erupted beneath the Cordilleran Ice Sheet during the Pleistocene. Its last eruption produced two small

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 that traveled 1 km to the west, along with a blanket of

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

that extends several km to the north and east of the cone.

Geology and history

Origins

Nazko Cone probably began erupting about 340,000 years ago and has grown steadily since then. Like all of the Anahim volcanoes, Nazko Cone has its origins in the

Anahim hotspot The Anahim hotspot is a hypothesized hotspot in the Central Interior of British Columbia, Canada. It has been proposed as the candidate source for volcanism in the Anahim Volcanic Belt, a long chain of volcanoes and other magmatic features th ...

—a plume of magma rising from deep in the Earth's mantle. The hotspot remains in a fixed position, while the North American Plate drifts over it at a rate of 2 to 3.3 centimetres per year. The upwelling of the hot magma creates volcanoes, and each individual volcano erupts for a few million years before the movement of the plate carries it away from the rising magma. The hotspot has existed for at least 13 million years, and the Anahim Volcanic Belt stretches almost 600 kilometres (400 mi) away from the hotspot. Currently, the hotspot lies under Nazko Cone, which is the youngest volcano in the Anahim Volcanic Belt.

7200 BP Eruption of Nazko Cone

The eruptive cycle of Nazko Cone 7200 years ago started with the eruption of two different progressions of fluid

s, an older grey basalt overlain by a younger, darker black basalt. The passive eruptions were followed by a period of

explosive eruption In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a Viscosity, viscous ...

s.Natural Resources Canada: Nazko Cone
This explosive activity built three overlapping cinder cones near the end of the explosive phase of activity. The last phase of explosive activity spread tephra to the north and east of the cones. The deepest deposits near the cones are over 3 m deep and thin to less than a few centimetres only a few kilometres away, which suggests that the explosive eruptions at Nazko Cone were fairly small. However, the last eruption from Nazko Cone could have started

forest fire A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a bushfire ( in Australia), dese ...

s, since there is

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, ca ...

inside the

tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...

layer.

Recent activity

The volcano has been dormant since the 7200 BP eruption. On October 10, 2007, a small swarm of earthquakes appeared 20 kilometres west of Nazko Cone.Chronology of Events in 2007 at Nazko Cone
Most of these earthquakes were magnitude 1.0 or less; some as strong as M 3.1 or 3.2 were centered 25 kilometres below the surface. The cause of this seismic activity is believed to be the upwelling of

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

because the area is not close to any faults or

tectonic plate Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

boundaries.

Hazards

Future eruptions from Nazko Cone are unlikely to cause many fatalities, due to the region's remoteness. There is active

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucksranch A ranch (from /Mexican Spanish) is an area of landscape, land, including various structures, given primarily to ranching, the practice of raising grazing livestock such as cattle and sheep. It is a subtype of farm. These terms are most often ap ...

ing in the region, and people engaged in these activities are at some risk. Lava flows are likely to flow only a few kilometres from the volcano which could possibly start

s in the dry region. Any future eruption is likely to affect low flying air traffic only, since eruptions would likely be in the form of Hawaiian eruption-

lava fountain 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 unde ...

s that create small

s and lava flows rather than voluminous ash clouds.

Monitoring

Nazko Cone has been an intensively monitored volcano by the

Geological Survey of Canada The Geological Survey of Canada (GSC; , CGC) is a Canadian federal government agency responsible for performing geological surveys of the country developing Canada's natural resources and protecting the environment. A branch of the Earth Science ...

since October 10, 2007. One of the most important tools is seismometry. About 5

seismometer A seismometer is an instrument that responds to ground displacement and shaking such as caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The out ...

s were set up around Nazko Cone to enable scientists to measure the intensities and locations of hundreds of small earthquakes every day. Since then, there have been more than 1000 small earthquakes recorded. Earthquakes can begin to increase years before an eruption actually starts. Another type of seismic activity occurs in the hours preceding an eruption. So-called harmonic tremor is a continuous "rumble" which contrasts with the normal seismic activity of sudden shocks and is believed to be caused by the rapid movement of magma underground. Volcanic tremor normally indicates an imminent eruption, although it may also be caused by shallow intrusions of magma which do not reach the surface. Another important indicator of what is happening underground is the shape of the volcano.

Tiltmeter A tiltmeter is a sensitive inclinometer designed to measure very small changes from the vertical level, either on the ground or in structures. Tiltmeters are used extensively for monitoring volcanoes, the response of dams to filling, the small ...

s measure very small changes in the profile of the volcano, and sensitive equipment measures distances between points on the volcano. As magma fills the shallow reservoirs below the summit, the mountain inflates.

Recent history

Nazko Cone was staked for

mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...

its

cinder Cinder or Cinders may refer to: In general * Ember, also called cinder * Ash, also called cinder * Scoria, or cinder, a type of volcanic rock In computing * Cinder (programming library), a C++ programming library for visualization *Cinder, Ope ...

and

in the early 1990s by the Canadian Pumice Corporation, and has since been steadily reduced to produce red industrial aggregate for landscaping. Before mining, the Nazko Cone was also a unique ecosystem. The vegetation included a complex of species. Very large old

Douglas fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is the tallest tree in the Pinaceae family. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Or ...

trees were common, growing in some of the more soil-like ash and

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 Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

White spruce White spruce is a common name for several species of spruce (''Picea'') and may refer to: * '' Picea engelmannii'', native to the Rocky Mountains and Cascade Mountains of the United States and Canada * ''Picea glauca ''Picea glauca'', the whi ...

was surprisingly common, although severely stunted, whereas

lodgepole pine ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpin ...

was not. There were some shallow

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

s and hollows below the volcano. To the west, following the lava flow mentioned above, is a unique

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

which appears to be saturated ash. What makes it unique is the fact that normally wetlands are saturated organic material such as

peat moss ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store water, since ...

. The wetland at Nazko Cone, however, is mixed organic and lava or ash, and the resultant ecosystem is quite unexpected.

Geothermal Potential

High heat flow in the Nazko Cone area is being evaluated as a potential source of geothermal heating.

References

External links

*
Volcano World description
{{Anahim Volcanic Belt Anahim Volcanic Belt Cinder cones of British Columbia VEI-3 volcanoes Pleistocene volcanoes Holocene cinder cones Polygenetic cinder cones Cariboo Land District One-thousanders of British Columbia Pleistocene British Columbia Holocene British Columbia