Big Pine volcanic field is a
volcanic field
A volcanic field is an area of Earth's crust that is prone to localized volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters of up to 100 volcanoes ...
in
Inyo County
Inyo County () is a county in the eastern central part of the U.S. state of California, located between the Sierra Nevada and the state of Nevada. In the 2020 census, the population was 19,016. The county seat is Independence. Inyo County is o ...
,
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
. The volcanic field covers a surface area of within the
Owens Valley
Owens Valley (Numic
Numic is a branch of the Uto-Aztecan language family. It includes seven languages spoken by Native American peoples traditionally living in the Great Basin, Colorado River basin, Snake River basin, and southern Great Pl ...
east of the
Sierra Nevada
The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...
and consists of
lava flows
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 un ...
, one
rhyolitic
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...
coulee
Coulee, or coulée ( or ) is a term applied rather loosely to different landforms, all of which refer to a kind of valley or drainage zone. The word ''coulee'' comes from the Canadian French ''coulée'', from French ''couler'' 'to flow'.
The ...
and about 40 volcanic vents including
cinder cones
A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or ...
. Some vents are simple conical cinder cones while others are irregular scoria cones.
Glaciers
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...
and
former lakes have modified lava flows.
Volcanic activity in the field commenced 1.2 million years ago and was controlled by a number of
faults which cross the valley. Activity continued into the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
with the youngest eruption generating cones and several lava flows about 17,000 years ago. A major road and the
Los Angeles Aqueduct
The Los Angeles Aqueduct system, comprising the Los Angeles Aqueduct (Owens Valley aqueduct) and the Second Los Angeles Aqueduct, is a water conveyance system, built and operated by the Los Angeles Department of Water and Power. The Owens Valley ...
would be threatened if volcanic activity restarted at Big Pine.
Geography and geomorphology
The Big Pine volcanic field (also known as Aberdeen volcanic field
) lies in the
Owens Valley
Owens Valley (Numic
Numic is a branch of the Uto-Aztecan language family. It includes seven languages spoken by Native American peoples traditionally living in the Great Basin, Colorado River basin, Snake River basin, and southern Great Pl ...
, around Aberdeen, California and between the towns of
Big Pine and
Independence
Independence is a condition of a person, nation, country, or state in which residents and population, or some portion thereof, exercise self-government, and usually sovereignty, over its territory. The opposite of independence is the statu ...
.
U.S. Route 395
U.S. Route 395 (US 395) is a U.S. Route in the western United States. The southern terminus of the route is in the Mojave Desert at Interstate 15 near Hesperia. The northern terminus is at the Canada–US border near Laurier, where the road ...
and the
Owens River
The Owens River is a river in eastern California in the United States, approximately long.U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed March 17, 2011, It drains into and through the ...
run through the field, the latter is dammed north of the field in the
Tinemaha Reservoir
Tinemaha Reservoir is a reservoir created by a dam on the Owens River in the Owens Valley. It is located in Inyo County, eastern California.
It is part of the Los Angeles Aqueduct system, operated by the Los Angeles Department of Water and Power. ...
.
The field covers and consists of 25
monogenetic volcano
A monogenetic volcanic field is a type of volcanic field consisting of a group of small monogenetic volcanoes, each of which erupts only once, as opposed to polygenetic volcanoes, which erupt repeatedly over a period of time. The small monogenetic ...
es and about 15 further vents. The field features volcanic cones on both sides of the valley, which take the form of symmetrical cones and irregular vents; the latter are found at the valley margin while the former are located on the valley floor. Crater Mountain and Red Mountain are two cones in the field.
Pyroclastic
Pyroclastic rocks (derived from the el, πῦρ, links=no, meaning fire; and , meaning broken) are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroc ...
material is usually found only close to the vents. A single
rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...
coulee
Coulee, or coulée ( or ) is a term applied rather loosely to different landforms, all of which refer to a kind of valley or drainage zone. The word ''coulee'' comes from the Canadian French ''coulée'', from French ''couler'' 'to flow'.
The ...
is also part of the field.
![Big Pine volcanic field - Crater Mountain from Fish Springs Rd](https://upload.wikimedia.org/wikipedia/commons/3/39/Big_Pine_volcanic_field_-_Crater_Mountain_from_Fish_Springs_Rd.JPG)
Around Aberdeen,
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 moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or und ...
s from diverse vents form a large field with
aa and
pahoehoe
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 und ...
forms and neatly preserved surface features. Lava flows reach lengths of
and have thicknesses of and sometimes lava flows from separate cones overlap, such as in
Papoose Canyon.
In the past,
pluvial lake
A pluvial lake is a body of water that accumulated in a basin because of a greater moisture availability resulting from changes in temperature and/or precipitation. These intervals of greater moisture availability are not always contemporaneous ...
s and
glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...
s extended over the Owens Valley. Volcanic activity occurred at the Big Pine volcanic field during that time and was influenced by these lakes and glaciers.
Owens Lake
Owens Lake is a mostly dry lake in the Owens Valley on the eastern side of the Sierra Nevada in Inyo County, California. It is about south of Lone Pine, California. Unlike most dry lakes in the Basin and Range Province that have been dry for th ...
spread through much of the valley during glacial times and cut shorelines into the lava flows. Glacial material and sediment covers some lava flows, and deep
well
A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...
s have found buried lava flows at depths of .
The basement in the region is formed by
pluton
In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
ic rocks of
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...
age,
metasedimentary
In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and er ...
and
metavolcanic
Metavolcanic rock is volcanic rock that shows signs of having experienced metamorphism. In other words, the rock was originally produced by a volcano, either as lava or tephra. The rock was then subjected to high pressure, high temperature or both ...
rocks which crop out in the
White Mountains and the
Sierra Nevada
The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...
; the valley floor is covered with
alluvium
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluv ...
. Tectonically,
Owens Valley
Owens Valley (Numic
Numic is a branch of the Uto-Aztecan language family. It includes seven languages spoken by Native American peoples traditionally living in the Great Basin, Colorado River basin, Snake River basin, and southern Great Pl ...
is a
graben
In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults.
Etymology
''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...
formed by the movement of the
Sierra Nevada-Great Valley block
Sierra (Spanish for "mountain range" and "saw", from Latin '' serra'') may refer to the following:
Places Mountains and mountain ranges
* Sierra de Juárez, a mountain range in Baja California, Mexico
* Sierra de las Nieves, a mountain range i ...
with respect to the rest of North America.
Farther south lies the
Coso volcanic field
The Coso Volcanic Field is located in Inyo County, California, at the western edge of the Basin and Range geologic province and northern region of the Mojave Desert. The Fossil Falls are part of the Coso Field, created by the prehistoric Owens ...
, which is also
geothermally active unlike Big Pine volcanic field.
Geologic context
Various processes have been proposed to explain the volcanism in the
Basin and Range province
The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating ...
. These include tectonic spreading which triggered the upwelling of
mantle material,
convection
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...
within the mantle owing to temperature and viscosity differences, the aftereffects of
Proterozoic
The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided ...
crustal boundaries, mantle currents and release of water by the
slab
Slab or SLAB may refer to:
Physical materials
* Concrete slab, a flat concrete plate used in construction
* Stone slab, a flat stone used in construction
* Slab (casting), a length of metal
* Slab (geology), that portion of a tectonic plate that i ...
of the
Farallon Plate
The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west c ...
and the
delamination
Delamination is a mode of failure where a material fractures into layers. A variety of materials including laminate composites and concrete can fail by delamination. Processing can create layers in materials such as steel formed by rolling and ...
of
crustal material. There are a number of volcanic fields in Eastern California and Big Pine is one of these.
Volcanic activity at Big Pine and Coso volcanic fields is linked to the tectonic spreading of the
Basin and Range province
The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating ...
, and vents at Big Pine are associated with
faults such as the
Owens Valley fault Owens may refer to:
Places in the United States
*Owens Station, Delaware
*Owens Township, St. Louis County, Minnesota
*Owens, Missouri
*Owens, Ohio
*Owens, Virginia
People
* Owens (surname), including a list of people with the name
* Owens Bro ...
, the
Sierra Nevada fault
The Sierra Nevada Fault is an active seismic fault along the eastern edge of the Sierra Nevada mountain block in California. It forms the eastern escarpment of the Sierra Nevada, extending roughly from just north of the Garlock Fault to the Casc ...
and the
White Mountains fault
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on ...
; faults have offset lava flows of the field. Seismic imaging of the
crust beneath the Big Pine volcanic field indicates that the
lithosphere
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust (geology), crust and the portion of the upper mantle (geology), mantle that behaves elastically on time sca ...
is thinner there than elsewhere.
Composition
The Big Pine volcanic field has erupted
basaltic
Basalt (; ) is an 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 surface of a rocky planet or moon. More than 90% of a ...
rocks spanning a range of composition from
alkali basalt
Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands, continental rifts and volcanic fields. Alkali basalt ...
to
basanite
Basanite () is an igneous, volcanic (extrusive) rock with aphanitic to porphyritic texture. It is composed mostly of feldspathoids, pyroxenes, olivine, and plagioclase and forms from magma low in silica and enriched in alkali metal oxides that s ...
, as well as one unit of
silicic
Silicic is an adjective to describe magma or igneous rock rich in silica. The amount of silica that constitutes a silicic rock is usually defined as at least 63 percent. Granite and rhyolite are the most common silicic rocks.
Silicic is the group ...
rocks.
Phenocryst
300px, feldspathic phenocrysts. This granite, from the Switzerland">Swiss side of the Mont Blanc massif, has large white plagioclase phenocrysts, triclinic minerals that give trapezoid shapes when cut through). 1 euro coins, 1 euro coin (diameter ...
s include
olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
,
plagioclase
Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more prope ...
and
clinopyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...
. The erupted rocks also contain
xenolith
A xenolith ("foreign rock") is a rock fragment (country rock) that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term ''xenolith'' is almost exclusively used to describe inclusions in igne ...
s such as
lherzolite
Lherzolite is a type of ultramafic igneous rock. It is a coarse-grained rock consisting of 40 to 90% olivine along with significant orthopyroxene and lesser amounts of calcic chromium-rich clinopyroxene. Minor minerals include chromium and alu ...
,
pyroxenite
Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite. Pyroxenites are classified into clinopyroxenites, orthopyroxenites, and the websteri ...
and
wehrlite.
The magmas erupted in the Big Pine volcanic field were generated by melting of
lithospheric
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years o ...
mantle that had been modified by
subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...
processes 1.8 billion years ago. Research conducted in 2008 suggested that the mixing and melting of two origin magmas is necessary to generate the observed rock compositions. After formation, the
magmas
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
at Big Pine quickly rose to the surface, preventing the formation of
rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...
s which would require the magmas to stall within the crust.
Climate and vegetation
Owens Valley is windy and sunny with yearly temperatures fluctuating with strong diurnal temperature fluctuations. The Owens Valley lies in the
rainshadow
A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side.
Evaporated moisture from water bodies (such as oceans and large lakes) is carri ...
of the Sierra Nevada and thus the climate of the valley is dry with about precipitation.
Vegetation in the valley is dominated by species adapted to
arid
A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ar ...
and
semiarid
A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-ar ...
climates and includes
Alkali sacaton,
big sagebrush
''Artemisia tridentata'', commonly called big sagebrush,MacKay, Pam (2013), ''Mojave Desert Wildflowers'', 2nd ed., , p. 264. Great Basin sagebrush or (locally) simply sagebrush, is an aromatic shrub from the family Asteraceae, which grows in ari ...
,
greasewood
Greasewood is a common name shared by several plants:
* ''Adenostoma fasciculatum'' is a plant with white flowers that is native to Oregon, Nevada, California, and northern Baja California. This shrub is one of the most widespread plants of the ...
,
Nevada saltbush,
rubber rabbitbrush
''Ericameria nauseosa'' (formerly ''Chrysothamnus nauseosus''), commonly known as Chamisa, rubber rabbitbrush, and gray rabbitbrush, is a shrub in the sunflower family (Aster) found in the arid regions of western North America.
Two subspeci ...
,
salt grass
''Distichlis spicata'' is a species of Poaceae, grass known by several common names, including seashore saltgrass, inland saltgrass, and desert saltgrass. This grass is native to the Americas, where it is widespread. It can be found on other con ...
and
shadscale
''Atriplex confertifolia'', the shadscale or spiny saltbush, is a species of evergreen shrub in the family Amaranthaceae, which is native to the western United States and northern Mexico
Mexico (Spanish: México), officially the United Me ...
. Plants cluster in places where water is available, such as on former stream courses, around
depressions and along
fault lines.
Eruption history
Volcanism at Big Pine occurred during the
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
and yielded a total volume of of rock. Activity lasted from 1.2 million years ago until 17,000 years ago, with the bulk of the rocks erupted between 500,000 and 100,000 years ago.
Glacial isostasy seems to influence eruption rates in the field, with eruptions suppressed during glacial times.
The oldest volcanic structures, 1.2 million years old, are found in the Oak Creek area and only erosional remnants of them are encountered. The
rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...
was erupted about 990,000 years ago, while later volcanism took place from 760,800 ± 22,800 years ago in Papoose Canyon (Papoose Canyon sequence) over 469,400 ± 9,200 years ago at Jalopy Cone, 90,500 ± 17,600 years ago at Quarry Cone, 61,600 ± 23,400 years ago at Volcanic Bomb Cone, 31,800 ± 12,100 years ago at Goodale Bee Cone (Aberdeen flow), 27,000 years ago at the Blackrock Springs lava to the about 17,000 years old Armstrong Canyon/Division Creek/Taboose Creek flows.
These (Armstrong Canyon/Division Creek/Taboose Creek) flows were erupted during the same episode, which created Armstrong Canyon cone, a series of
scoria cone
Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock that was ejected from a volcano as a molten blob and cooled in the air to form discrete grains or clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''G ...
s and the three lava flows along a long tract of the Sierra Nevada fault. This episode may have generated as much as of
tephra
Tephra is fragmental material produced by a 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, they rem ...
, and lava flows interacted with water forming
palagonite
Palagonite is an alteration product from the interaction of water with volcanic glass of chemical composition similar to basalt. Palagonite can also result from the interaction between water and basalt melt. The water flashes to steam on contact w ...
. The lavas from this event and the Blackrock Springs lava were later eroded by
Owens Lake
Owens Lake is a mostly dry lake in the Owens Valley on the eastern side of the Sierra Nevada in Inyo County, California. It is about south of Lone Pine, California. Unlike most dry lakes in the Basin and Range Province that have been dry for th ...
during its
last glacial maximum
The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent.
Ice sheets covered much of Northern North America, Northern Eur ...
highstand.
Hazards
The volcanoes in Eastern California such as
Long Valley, Coso and Big Pine are still considered hazardous. The
Los Angeles Aqueduct
The Los Angeles Aqueduct system, comprising the Los Angeles Aqueduct (Owens Valley aqueduct) and the Second Los Angeles Aqueduct, is a water conveyance system, built and operated by the Los Angeles Department of Water and Power. The Owens Valley ...
and US. Route 395 may be impacted by future eruptions at Big Pine; the former contributes of the water supply of
Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...
(from less than one quarter to more than half of the city's water consumption)
while the latter is frequently used by people travelling between
Mammoth Lakes
Mammoth Lakes is a town in Mono County, California, and is the county's only incorporated community. It is located immediately to the east of Mammoth Mountain, at an elevation of . As of the 2020 United States Census, the population was 7,191, r ...
and
Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...
.
Gallery
File:Owens Valley, California.jpg, Cinder cones in the background
File:Tinemaha Reservoir.jpg, Tinemaha Reservoir, with cinder cones in the middle and left parts of the image
File:SierraEscarpmentCA.jpg, Owens Valley, with cones visible in the centre-right part of the image
References
Sources
*
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{{refend
Volcanoes of Inyo County, California
Owens Valley
Natural history of Inyo County, California
Volcanic fields of California
Volcanoes of California