Markagunt Plateau 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 southern

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. Formed in a region of older volcanics, it consists of several

cinder cone 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 o ...

s 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 moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or und ...

s. Some of the lava flows feature

lava tube A lava tube, or pyroduct, is a natural conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow. If lava in the tube empties, it will leave a cave. Formation A lava tube is a type of lava ca ...

s such as

Mammoth Cave Mammoth Cave National Park is an American national park in west-central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. Since the 1972 unification of Mammoth Cave with the even-longer system under F ...

, while others have formed

lava dam A volcanic dam is a type of natural dam produced directly or indirectly by volcanism, which holds or temporarily restricts the flow of surface water in existing streams, like a man-made dam. There are two main types of volcanic dams, those creat ...

s and lakes like

Navajo Lake Navajo Lake is a reservoir located in San Juan County and Rio Arriba County in northwestern New Mexico, in the southwestern United States. Portions of the reservoir extend into Archuleta County in southern Colorado. The lake is part of the C ...

. Volcanism took place during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene 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 ...

but may have continued into the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

; legends of the

Southern Paiute The Southern Paiute people are a tribe of Native Americans who have lived in the Colorado River basin of southern Nevada, northern Arizona, and southern Utah. Bands of Southern Paiute live in scattered locations throughout this territory and ha ...

may reflect past eruptions.

Geography and geomorphology

The Markagunt Plateau is in southern

in the

counties A county is a geographic region of a country used for administrative or other purposesChambers Dictionary, L. Brookes (ed.), 2005, Chambers Harrap Publishers Ltd, Edinburgh in certain modern nations. The term is derived from the Old French ...

Iron County, Garfield County and Kane County.

Cedar City Cedar City is the largest city in Iron County, Utah, United States. It is located south of Salt Lake City, and north of Las Vegas on Interstate 15. It is the home of Southern Utah University, the Utah Shakespeare Festival, the Utah Summer Gam ...

lies west and

Kanab Kanab ( ) is a city in and the county seat of Kane County, Utah, Kane County, Utah, United States.Find a Co ...

south of the volcanic field, which is crossed by

Utah State Route 14 State Route 14 (SR-14) is a state highway in southern Utah, running for in Iron and Kane Counties from Cedar City to Long Valley Junction. The highway has been designated the Markagaunt High Plateau Scenic Byway as part of the Utah Scenic Byway ...

Utah State Route 143 State Route 143 (SR-143) is a state highway in the U.S. state of Utah. The entire highway has been designated the Brian Head-Panguitch Lake Scenic Byway as part of the Utah Scenic Byways program. This road has also been designated as Utah's Pa ...

and

Utah State Route 148 State Route 148 (SR-148) is a state highway in the U.S. state of Utah. The entire highway has been designated the Cedar Breaks Scenic Byway as part of the Utah Scenic Byways and National Forest Scenic Byway programs. Route description The ro ...

. Towns in the area include Duck Creek Village and Mammoth Creek. The volcanic field is on a plateau bordered to the south by the Pink Cliffs and to the west by the

cliff In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on co ...

s of

Cedar Breaks National Monument Cedar Breaks National Monument is a U.S. National Monument located in the U.S. state of Utah near Cedar City. Cedar Breaks is a natural amphitheater, stretching across , with a depth of over . The elevation of the rim of the amphitheater is over ...

, and features

s and over 25

s mostly between

Panguitch Lake Panguitch Lake () was originally a large natural lake (777 acres) that has now been expanded by the creation of a dam to become a reservoir with a maximum surface area of . The lake, which drains into the Sevier River is located on the Markag ...

and

although older volcanics occur south of Panguitch. Some cones such as Hancock Peak, Henrie Knolls and Strawberry Knolls are up to high, and Miller Knoll cone is surrounded by three satellite vents. Past

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...

has eroded some vents. Some recent vents formed along

lineament ''See also Line (geometry)'' A lineament is a linear feature in a landscape which is an expression of an underlying geological structure such as a fault. Typically a lineament will appear as a fault-aligned valley, a series of fault or fold-aligne ...

s and faults; this includes the chain of over 19 cinder cones that generated the Henrie Knolls flows.

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 in the Markagunt Plateau are blocky and have flow fronts which reach heights of ; many were erupted from

fissure vent A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive eruption, explosive activity. The vent is often a few metres wide an ...

s. Some of the lava flows of Markagunt Plateau are among the youngest in Utah; these are sparsely vegetated and blocky, while others are cut by streams and stream terraces. Bowers Cave and

are

s set in lava flows on the Markagunt Plateau, the long Duck Creek Lava Tube is among the longest and highest lava tubes in the United States. Perennial ice and pools of water are widespread in the tubes, which are typically accessible through collapsed portions of the tubes. Lava flows almost reach

. Lava flows have blocked surface drainages, forming

which drains underground into two watersheds and was later further

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

med by humans; another lava-dammed lake downstream from Navajo Lake is now a

meadow A meadow ( ) is an open habitat, or field, vegetated by grasses, herbs, and other non-woody plants. Trees or shrubs may sparsely populate meadows, as long as these areas maintain an open character. Meadows may be naturally occurring or artifi ...

and Blue Spring Valley also saw the development of

s. As a consequence, water on the Markagunt Plateau flows underground through

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

s developed in

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

rocks, and the burial of surface drainages by highly permeable lava flows likely aided in their development; some sinkholes have formed in basalt and other

karstic Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

features are also found in the volcanic field. Many streams and ephemeral creeks head in

spring Spring(s) may refer to: Common uses * Spring (season) Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...

s or disappear into sinkholes.

Geology

Geologically, southwestern Utah is at the margin between the geologic provinces known as the

Colorado Plateau The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province covers an area of ...

and 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 ...

, the former of which features flat lying sediments while the latter is characterized by steep horsts and

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 ...

s. After the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

and

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

, during which volcanism was characterized by

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

s and

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...

es, beginning 8 million years ago smaller volumes of mostly

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 ...

magma 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 ...

formed

lava dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's 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 v ...

es,

volcanic cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and ...

s and

volcanic plug A volcanic plug, also called a volcanic neck or lava neck, is a volcanic object created when magma hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of high gas pressure if rising volatile-charged mag ...

s. The Markagunt Plateau is part of the High Plateaus geologic province, in the

and at its margins with the Basin and Range Province. It is a wide fault-bounded block and the

basement A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ...

underneath the volcanoes is formed by various

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

sedimentary or volcanic rocks. Volcanism in the region has been ongoing for the last 5 million years. The volcanism is considered to be intraplate and unrelated to either

mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hot ...

s or

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 ...

Composition

Volcanic rocks erupted on the Markagunt Plateau range 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 ...

over

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 ...

and

basaltic andesite Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...

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 predomi ...

and

latite Latite is an igneous, volcanic rock, with aphanitic- aphyric to aphyric-porphyritic texture. Its mineral assemblage is usually alkali feldspar and plagioclase in approximately equal amounts. Quartz is less than five percent and is absent in a f ...

, and define

calc-alkaline The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic mag ...

and

tholeiitic 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 magma ...

suites which appear to become more silicic over time.

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

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) ...

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 ...

and

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 ...

, with not all minerals present in all flows. Volcanic rocks at Markagunt Plateau are unusual for the common occurrence of subalkaline volcanics; most other recent volcanic centres in the

have produced

s. Mixing between crustal melts and primitive magmas may explain this tendency, while the presence of

tholeiite 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 magma i ...

may indicate the occurrence of

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...

ing processes in western Utah.

Climate and vegetation

Annual precipitation is about per year and mostly occurs in the form of

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...

from the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

, although summer

monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...

precipitation also occurs. Most of the plateau is part of

Dixie National Forest Dixie National Forest is a United States National Forest in Utah with headquarters in Cedar City. It occupies almost two million acres (8,000 km²) and stretches for about across southern Utah. The largest national forest in Utah, it str ...

; trees include

aspen Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the ''Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (China ...

spruce A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

and fir with an understory consisting of

juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' () of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere, from the Arcti ...

, '' Mertensia arizonica'' and mountain gooseberry and the vegetation covers most surfaces except for the younger volcanoes and

canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...

walls. Additionally, in

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

es vegetation includes hydrophilic plants such as

cattail ''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrush or reedmace, in American English as reed, cattail, or punks, in A ...

s, while

grows on

s. File:Duck Lake, Duck Creek Village, Utah (3446874928).jpg, Duck Lake File:Utah State Route 14 near Navajo Lake.JPG, Utah State Route 14 near Navajo Lake File:Scenic fall colours along Utah Hwy 14 - (22419172589).jpg, Duck Lake in autumn File:Navajo Lake, UT 9-10 (15357081738).jpg, Navajo Lake

Eruption history

Volcanism in the Markagunt volcanic field occurred in three stages. The first stage saw activity mainly at the margins of the Markagunt Plateau between 5.3 and 2.8 million years ago; the cinder cones and lava flows produced during this stage are heavily eroded. The second stage occurred along the Sevier fault and in the southern part of the field between 800,000 and 500,000 years ago; its cones and lava flows are moderately eroded. The third group was emplaced during the middle

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 ...

and

. Some individual vents: * Dickinson Hill cinder cone and lava flows, 5.3 million years old. * Houston Mountain flows, vent probably buried beneath younger volcanics. 5.3 million years old. * Rock Canyon cinder cone and lava flow. Perhaps coeval with Dickinson Hill and may also be the source of the 4.98 - 4.94 million years old Red Canyon flows. * Sidney Peaks basalt, probably of

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

and include Lake Hollow, Duck Creek, Midway Creek, Horse Pasture, Henrie Knolls, Red Desert, Navajo Lake, Dry Valley and the various Miller Knoll and Panguitch Lake flows and cinder cones.

Latest Pleistocene and Holocene

The appearance and

weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ...

characteristics of many volcanic structures imply that they have a recent age. Argon-argon dating has yielded an imprecise date of 58,000 ± 35,000 years ago for the Henrie Knolls lava flows. On the Miller Knoll flows,

surface exposure dating Surface exposure dating is a collection of geochronological techniques for estimating the length of time that a rock has been exposed at or near Earth's surface. Surface exposure dating is used to date glacial advances and retreats, erosion histo ...

has yielded ages of 38,000 - 36,000 years ago for the middle member and of 34,000 ± 4,000 and 32,000 ± 3,000 for two other flows which are likely of the same age. The middle member is overlaid by the Dry Valley flow which is also younger than the other two flows. The precise date of the last eruption is not known but eight

s in the volcanic field appear to be less than 10,000 years old. The

settled into the region after 1,100 AD and their legends may contain references to

s. Aside from volcanism, landsliding, aeolian,

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but a ...

and

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

sedimentation took place in the area,

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...

s built

beaver dam A beaver dam or beaver impoundment is a dam built by beavers to create a pond which protects against predators such as coyotes, wolves and bears, and holds their food during winter. These structures modify the natural environment in such a way t ...

s on watercourses and

peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...

accumulated at several sites. During the

, the Bull Lake glaciation and the Pinedale glaciation took place on the Markagunt Plateau and eroded and buried some lava flows.

Hazards

Large volcanic eruptions in the 1980s such as

Mount St. Helens Mount St. Helens (known as Lawetlat'la to the indigenous Cowlitz people, and Loowit or Louwala-Clough to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United St ...

raised public awareness about the dangers emanating from volcanic activity. While most fatalities during volcanic eruptions occurred at

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 ...

volcanoes,

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 ...

eruptions like these that occurred in

in the past are also potential sources of danger. The Markagunt Plateau is considered to be a low-risk volcano. Renewed activity may impact the

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

and popular recreation site of

less than south of the Markagunt Plateau volcanic field as well as

and

U.S. Route 89 U.S. Route 89 (US 89) is a north–south United States Numbered Highway with two sections, and one former section. The southern section runs for from Flagstaff, Arizona, to the southern entrance of Yellowstone National Park. The northern sectio ...

which are constructed across lava flows from the volcanic field.

References

Sources

* * * * * * *

External links

{{Authority control Plateaus of Utah Colorado Plateau Volcanic fields of Utah Volcanoes of Utah Landforms of Garfield County, Utah Landforms of Iron County, Utah Landforms of Kane County, Utah Landforms of Washington County, Utah