Mount Thielsen, or Big Cowhorn (
Klamath Klamath may refer to:
Ethnic groups
*Klamath people, a Native American people of California and Oregon
**Klamath Tribes, a federally recognized group of tribes in Oregon
*Klamath language, spoken by the Klamath people
Places in the United States
* ...
: hisc’akwaleeʔas), is an
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
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 ...
in the Oregon
High Cascades, near
Mount Bailey. Because eruptive activity ceased 250,000 years ago, glaciers have heavily eroded the volcano's structure, creating precipitous slopes and a
horn-like peak. The spire-like shape of Thielsen attracts lightning strikes and creates
fulgurite, an unusual mineral. The prominent horn forms a centerpiece for the
Mount Thielsen Wilderness
The Mount Thielsen Wilderness is a wilderness area located on and around Mount Thielsen in the southern Cascade Range of Oregon in the United States. It is located within the Deschutes, Umpqua, and Fremont–Winema national forests. It wa ...
, a reserve for recreational activities such as skiing and hiking. Thielson is one of
Oregon's Matterhorns
Oregon's Matterhorns is an informal group of volcanoes in the Cascade Range, in the American state of Oregon, named after the original Matterhorn. The Pacific Crest Trail passes near all of the volcanoes which constitute Oregon's Matterhorns.
O ...
.
Thielsen was produced 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 ...
of the
Juan de Fuca Plate under the
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...
.
Volcanism near the Cascades dates back to 55
million years ago
The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds.
Usage
Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...
(mya), and extends from
British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
to California. Thielsen is part of the High Cascades, a branch of the main Cascades range that includes several Oregon volcanoes less than 3.5 million years old; it is also a member of a group of extinct volcanoes
distinguished by their sharp peaks.
The area surrounding the volcano was originally inhabited by Klamath Native Americans, and was later encountered by settlers. One of the visitors was Jon Hurlburt, an early explorer of the area who named the volcano after the engineer Hans Thielsen. Later explorers discovered nearby
Crater Lake. The volcano was not analyzed until 1884, when a team from the
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
sampled its fulgurite deposits.
History
The area was originally inhabited by
Chinook Native Americans, who referred to the mountain as "Hischokwolas";
the
Klamath Klamath may refer to:
Ethnic groups
*Klamath people, a Native American people of California and Oregon
**Klamath Tribes, a federally recognized group of tribes in Oregon
*Klamath language, spoken by the Klamath people
Places in the United States
* ...
call it "hisc'akwaleeas". Jon Hurlburt, a Polish explorer, renamed the volcano after
Hans Thielsen
Hans may refer to:
__NOTOC__ People
* Hans (name), a masculine given name
* Hans Raj Hans, Indian singer and politician
** Navraj Hans, Indian singer, actor, entrepreneur, cricket player and performer, son of Hans Raj Hans
** Yuvraj Hans, Punjabi a ...
, a railroad engineer and builder who played a major role in the construction of the
California and Oregon Railroad
The Oregon and California Railroad was formed from the Oregon Central Railroad when it was the first to operate a stretch south of Portland in 1869. This qualified the railroad for land grants in California, whereupon the name of the railroad s ...
.
In 1884 a United States Geological Survey team headed by J. S. Diller began studying the mountains of the Cascade Range. Their intended destinations included Thielsen, which was climbed and sampled for its
fulgurite variant. Thielsen's spire-like top is hit by lightning so frequently that some rocks on the summit have melted into a rare
mineraloid
A mineraloid is a naturally occurring mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amor ...
known as
lechatelierite, a variety of fulgurite. The mountain has earned the nickname "the
lightning rod of the Cascades".
Apart from study, Thielsen and the rest of the Crater Lake area features heavily into 19th- and early 20th century exploration. In 1853, miners from Yreka
Yreka ( ) is the county seat of Siskiyou County, California, United States, near the Shasta River; the city has an area of about , most of it land. As of the 2020 United States Census, the population was 7,807, reflecting a meager increase fro ...
first described Crater Lake; one called it "the bluest water he had ever seen", another "deep blue lake". The first published description was written by Chauncy Nye
Chauncey Nye (1823–1900) was a pioneer of the U.S. state of Oregon who was best known as the first person to publish an account about Crater Lake.
Biography
Born in Michigan in 1823 to Nathan Nye, he accompanied his brother Nathan B. Nye (1831†...
for the ''Jacksonville Sentinel
The ''Oregon Sentinel'' was the first newspaper in southern Oregon. It was published in Jacksonville, Oregon from 1855 to 1888. The Oregon Sentinel was founded by pioneer William G. T'Vault, and was initially named the ''Table Rock Sentinel'', cha ...
'' in 1862. Nye recalled an expedition of gold prospectors where they passed a lake of a deep blue color. Native Americans lived in the area and grew irritable towards new settlers in the area. In 1865, Fort Klamath was built as a protective sanctuary. A wagon road was built to connect the Rogue Valley to the fort. In late 1865, two hunters ventured upon the lake; more explorers followed. By then, the lake became famous for its distinctive color, and crowds flocked to see it. The first known non-Native American to stand on the shore of Crater Lake was Sergeant Orsen Stearns, who climbed down into the caldera. A friend, Captain F.B. Sprague, gave it the name "Lake Majesty". Tourism continued until May 22, 1902; on that day, Theodore Roosevelt
Theodore Roosevelt Jr. ( ; October 27, 1858 – January 6, 1919), often referred to as Teddy or by his initials, T. R., was an American politician, statesman, soldier, conservationist, naturalist, historian, and writer who served as the 26t ...
designated the lake and surrounding area a national park.
Geography
Regional
The Cascade Range
The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...
was produced by convergence of the North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...
with the subducting Juan de Fuca Plate. Active volcanism has taken place for approximately 36 million years; the nearby Challis Range features complexes as old as 55 mya
Mya may refer to:
Brands and product names
* Mya (program), an intelligent personal assistant created by Motorola
* Mya (TV channel), an Italian Television channel
* Midwest Young Artists, a comprehensive youth music program
Codes
* Burmese ...
. Most geologists believe that activity in the Cascades has been relatively intermittent, producing up to 3,000 volcanic calderas at a time. Frequent volcanism within the last 10,000 years created complexes from Mount Garibaldi
Mount Garibaldi (known as Nch'kaý to the indigenous Squamish people) is a dormant stratovolcano in the Garibaldi Ranges of the Pacific Ranges in southwestern British Columbia, Canada. It has a maximum elevation of and rises above the surroundi ...
in British Columbia to north California's Lassen Peak complex. Remarkably different from state to state, the volcanism ranges from large volcanoes to zones of many smaller geologic features such as lava shield
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 vi ...
s and 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. Volcanic peaks of the Cascade Mountains are grouped into two ranges, called the ''High Cascades'' and the ''Western Cascades''; Thielsen is part of the High Cascades, which are east of the Western Cascades.[
]
Local
Diamond Lake, formed by one of Thielsen's eruptions,[Molhlenbrock.] lies to the west of Mount Thielsen and beyond lies Mount Bailey, a much less eroded and younger 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 ...
. Thielsen's sharp peak is a prominent feature of the skyline visible from Crater Lake National Park
Crater Lake National Park is an American national park located in southern Oregon. Established in 1902, Crater Lake is the fifth-oldest national park in the United States and the only national park in Oregon. The park encompasses the caldera of ...
. All three volcanoes are part of the Oregon High Cascades, a range that sections off the stratovolcanoes of Oregon that are younger than 3.5 million years. The High Cascades include Mount Jefferson, the Three Sisters, Broken Top
Broken Top is a glacially eroded complex volcano, complex stratovolcano. It lies in the Cascade Volcanic Arc, part of the extensive Cascade Range in the U.S. state of Oregon. Located southeast of the Three Sisters (Oregon), Three Sisters peaks, ...
, and other stratovolcanoes and remnants.
Rock in the area ages from the Upper Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58[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 ...](_blank)
. Basalt and basaltic andesite comprise newer volcanoes atop the High Cascades: Major volcanic centers include Mount Hood, Three Sisters / Broken Top, Mount Mazama (Crater Lake), and Mount Jefferson. All have produced diverse eruptions, including both lava flows and pyroclastic eruptions, and variability in composition between dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...
, 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 even 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 ...
(except for Mount Hood, which is not known to have produced rhyolite). Thielsen is part of a series of extinct volcanoes in Oregon termed pyramidal peak
A pyramidal peak, sometimes called a glacial horn in extreme cases, is an angular, sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point. Pyramidal peaks are often examples o ...
s or "the Matterhorns" for their steep, spire-like summits; Thielsen is the highest at . Other Matterhorns include Mount Washington
Mount Washington is the highest peak in the Northeastern United States at and the most topographically prominent mountain east of the Mississippi River.
The mountain is notorious for its erratic weather. On the afternoon of April 12, 1934, ...
, Three Fingered Jack
Three Fingered Jack is a summit of a shield volcano of the Cascade Range in the U.S. state of Oregon. Formed during the Pleistocene Epoch (geology), epoch, the mountain consists mainly of basaltic andesite lava and was heavily glacier, glaciat ...
, Mount Bailey, and Diamond Peak. Unlike other mountains in the High Cascades, all these volcanoes became extinct 250,000–100,000 years ago, and their summits endured the last few ice age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...
s, accounting for their distinct shapes.[
]
Geology
Thielsen has been so deeply eroded by 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 that there is no summit crater and the upper part of the mountain is more or less a horn
Horn most often refers to:
*Horn (acoustic), a conical or bell shaped aperture used to guide sound
** Horn (instrument), collective name for tube-shaped wind musical instruments
*Horn (anatomy), a pointed, bony projection on the head of various ...
. Thielsen is a relatively old Cascade
Cascade, Cascades or Cascading may refer to:
Science and technology Science
*Cascade waterfalls, or series of waterfalls
* Cascade, the CRISPR-associated complex for antiviral defense (a protein complex)
* Cascade (grape), a type of fruit
* Bioc ...
volcano, and cone-building eruptions stopped relatively early. Erosion caused during the last two or three ice age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...
s remains visible.[ ]Subsidence
Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope move ...
of the last material in Thielsen's crater moved its youngest lava more than above the active crater.
On the mountain past lava flows are diverse, some as thick as , others as thin as . Stack-like figures composed of breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix.
The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of di ...
and past flow deposits are as thick as . The placement of these flows suggest that they were generated by spatter emitted by fountains in the cone.[ On the sides of the mountain are bands of ]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 ...
, a clay formed from iron-rich tephra making up the body of the volcano.[ Basalt taken from the volcano contained ]pyroxene
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) ...
, hypersthene material, and feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
s.
Other notable formations in the vicinity include Howlock Mountain, Windigo Butte, and Tolo Mountain. Other than Crater Lake, little water flows on the surface, but small streams have formed in canyons excavated by glaciers.
Composition
The volcanic cone of Mount Thielsen sits atop prior shield volcanoes, and has a volume of . The cone was built from 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 ...
, a common component of other shield volcanoes in the Oregon Cascades,[ breccia, and ]tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...
, and it is intruded by dikes
Dyke (UK) or dike (US) may refer to:
General uses
* Dyke (slang), a slang word meaning "lesbian"
* Dike (geology), a subvertical sheet-like intrusion of magma or sediment
* Dike (mythology), ''Dikē'', the Greek goddess of moral justice
* Dikes, ...
.[Bishop and Allen, p. 121.] A coalesced volcanic cone, it formed as pyroclastics erupted and fountains spewed lava.[ Glaciers cut and deformed the cone, eroding its upper sector. This erosion opened the interior of Thielsen for observation. Within the cone, ]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 ...
, pyroclastic flow
A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of bu ...
deposits, and strata 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 volcanic ash, are easily visible.[ Potassium-argon dating of deposits in the cone suggests that Thielsen is at least 290,000 years old. Since its eruption stopped about 250,000–100,000 years ago, the period of eruptive activity was short in time. The eruptions of the cone came in three phases: a period where lava flows built up its cone, one where more explosive pyroclastic eruptions took place, and the final period, in which pyroclastic and material of lava-based origin were erupted together forming a weak cone encircled by long deposits.][
]
Glaciation
Glaciers were present on the volcano until the conclusion of the Little Ice Age
The Little Ice Age (LIA) was a period of regional cooling, particularly pronounced in the North Atlantic region. It was not a true ice age of global extent. The term was introduced into scientific literature by François E. Matthes in 1939. Ma ...
, at the beginning of the 20th century.[ ]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 ...
glaciers have largely eroded Thielsen's caldera, exposing its contents.[ The last glacier on the mountain, the small ]Lathrop Glacier
Lathrop Glacier was in the U.S. state of Oregon. The glacier was situated in the Cascade Range at an elevation generally above on the steep northeast slope of Mount Thielsen, an extinct shield volcano. Lathrop Glacier consisted of two small b ...
located in the northern cirque
A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landform ...
, melted at some point after 2016. Whilst the glaciation was previously extensive, volcanic ash from eruptive activity at Mount Mazama has almost certainly masked contents.[
]
Fulgurites
Fulgurites (substances that form when lightning melts rock)[Harris, pp. 157–165.] on the volcano are restricted to the very pinnacle of the mountain, and are only found between the top and of its summit. Lightning strikes the summit regularly, creating patches of "brownish black to olive-black glass"[ that resemble "greasy splotches of enamel paint".][ These range from a few centimeters in diameter to long, narrow lines up to long. Their appearance also varies: While some patches are rough and spongy, others are flat. Inspection of the fulgurite reveals a ]homogenous
Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, siz ...
glass over a layer of basalt; in between, a stratum
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...
made of materials such as feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
, pyroxene
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) ...
, and 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 ...
exists.[
]
Ecology
A grove of enormous incense cedar
''Calocedrus'', the incense cedar (alternatively spelled incense-cedar), is a genus of coniferous trees in the cypress family Cupressaceae first described as a genus in 1873. It is native to eastern Asia and western North America.
The generi ...
s exists near Diamond Lake, and there is a forest of ponderosa pine at the nearby Emile Big Tree Trail. The Umpqua National Forest
Umpqua National Forest, in southern Oregon's Cascade Range, covers an area of in Douglas County, Oregon, Douglas, Lane County, Oregon, Lane, and Jackson County, Oregon, Jackson counties, and borders Crater Lake National Park. The four ranger di ...
features swordferns and Douglas fir
The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...
s.[ Rocky Mountain elks, pronghorns, and mule deer, ]bobcat
The bobcat (''Lynx rufus''), also known as the red lynx, is a medium-sized cat native to North America. It ranges from southern Canada through most of the contiguous United States to Oaxaca in Mexico. It is listed as Least Concern on the IUC ...
s, black bears, and mountain lions live in the Fremont–Winema National Forest. The forest's rivers support populations of trout
Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salmoni ...
, and the lakes contain fish such as the largemouth bass
The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but ...
. The forest is inhabited by avian species such as mallard
The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...
s, American bald eagle
The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche as ...
s, Canada geese, and whistling swans. Peregrine falcon
The peregrine falcon (''Falco peregrinus''), also known as the peregrine, and historically as the duck hawk in North America, is a Cosmopolitan distribution, cosmopolitan bird of prey (Bird of prey, raptor) in the family (biology), family Falco ...
s and Warner sucker
The Warner sucker (''Catostomus warnerensis'') is a rare species of freshwater ray-finned fish in the family Catostomidae. Native to Oregon in the United States and found only in the Warner Lakes, Warner Basin, its distribution extends just into ...
s also infrequently enter its boundaries.
The lower slopes of Mount Thielsen are heavily forested, with low diversity of plant species. A forest of mountain hemlock and fir
Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family (biology), family Pinaceae. They are found on mountains throughout much of North America, North and Central America, Europe, Asia, and North Africa. The ...
grows up to the timberline at about . Near the peak of the volcano, whitebark pine
''Pinus albicaulis'', known by the common names whitebark pine, white bark pine, white pine, pitch pine, scrub pine, and creeping pine, is a conifer tree native to the mountains of the western United States and Canada, specifically subalpine ...
prevails.
Recreation
Mount Thielsen lies in the southern section of the Mount Thielsen Wilderness
The Mount Thielsen Wilderness is a wilderness area located on and around Mount Thielsen in the southern Cascade Range of Oregon in the United States. It is located within the Deschutes, Umpqua, and Fremont–Winema national forests. It wa ...
, which is part of the Deschutes, Umpqua and Fremont–Winema national forests. On the west, the wilderness borders the Oregon Cascades Recreation Area, a area set aside by Congress in 1984. The wilderness and forests offer several activities related to the mountain, such as hiking and skiing. The wilderness covers around the volcano, featuring lakes and alpine parks. It also contains of the Pacific Crest National Scenic Trail
The Pacific Crest Trail (PCT), officially designated as the Pacific Crest National Scenic Trail, is a long-distance hiking and equestrian trail closely aligned with the highest portion of the Cascade and Sierra Nevada mountain ranges, which lie ...
, accessible from a trailhead
A trailhead is the point at which a trail begins, where the trail is often intended for hiking, biking, horseback riding, or off-road vehicles. Modern trailheads often contain rest rooms, maps, sign posts and distribution centers for information ...
along Oregon Highway 138. In 2009 the trail was selected as Oregon's best hike. Three skiing trails exist on the mountain, all of black diamond rating. They follow several trails through the wilderness from the bowl of the mountain.[
]
References
Bibliography
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{{DEFAULTSORT:Thielsen, Mount
Cascade Range
Cascade Volcanoes
Extinct volcanoes
Fremont–Winema National Forest
Landforms of Douglas County, Oregon
Mountains of Douglas County, Oregon
Mountains of Klamath County, Oregon
Mountains of Oregon
Pleistocene shield volcanoes
Polygenetic shield volcanoes
Shield volcanoes of the United States
Subduction volcanoes
Umpqua National Forest
Volcanoes of Klamath County, Oregon
Volcanoes of Oregon
Volcanoes of the United States