Mount McLoughlin

Mount McLoughlin is a dormant steep-sided stratovolcano, or composite volcano, in the Cascade Range of southern Oregon, United States. Located in the Sky Lakes Wilderness, it is one of the volcanic peaks in the Cascade Volcanic Arc, within the High Cascades sector. A prominent landmark for the Rogue River Valley, the mountain is north of Mount Shasta, and south-southwest of Crater Lake. It was named around 1838 after John McLoughlin, a Chief Factor for the Hudson's Bay Company. Mount McLouglin's prominence has made it a landmark to Native Americans and others for thousands of years.

McLoughlin consists largely of basaltic andesite. It underwent three major eruptive periods before its last activity took place between 30,000 and 20,000 years ago. It is not currently monitored for activity or deformation. Diverse species of flora and fauna inhabit the area, which is subject to frequent snowfall and temperature variation between seasons. The Pacific Crest Trail skirts the eastern and northern sides and also accesses the only trail to the summit, the Template:Convert McLoughlin Trail 3716. The mountain can also be skied.

Geography

File:Oregon volcanoes map.gif

Location in Oregon relative to other major volcanoes

The major landmark for the Rogue River Valley,<ref name=oreenc>Template:Cite encyclopedia</ref> Mount McLoughlin reaches an elevation of Template:Convert.<ref name=ngs/>Template:Ref The tallest volcano in between Mount Shasta — located Template:Convert to the southTemplate:Sfn — and South Sister Template:Convert to the north, it lies in the Cascade Range, in the southern portion of the U.S. state of Oregon.<ref name=ngs/> Most of the volcano lies in Jackson County,<ref name=wilamxa/><ref name=maalsi/> though the eastern side of its base lies in Klamath County.<ref name=oreenc/> It is the sixth tallest peak in Oregon,Template:Sfn but despite its height, Mount McLoughlin only has a volume of Template:Convert.<ref name=oregonstate>Template:Cite web</ref>

The volcano includes the Wilámxa Tip and Máalsi Tip peaks, which occur on its flanks at elevations of Template:Convert<ref name=wilamxa>Template:Cite gnis</ref> and Template:Convert,<ref name=maalsi>Template:Cite gnis</ref> respectively. It can be seen from the Interstate 5 and U.S. Route 97 highways.Template:Sfn From the southwest and southeast, it has a symmetrical appearance, but the northeastern flank of the volcano has been eroded and transformed into a hollow amphitheater.Template:Sfn

Wilderness

McLoughlin lies within the Sky Lakes Wilderness area,<ref name="USGS"/> part of the Template:Nowrap and the Fremont–Winema National Forests.<ref name=oreenc/> The Sky Lakes Wilderness covers an area of Template:Convert, with a width of Template:Convert and a length of Template:Convert. Designated by the U.S. Congress in 1984, it stretches from Crater Lake National Park to Oregon Route 140 at the south and ranges in elevation from Template:Convert in the Middle Fork canyon of the Rogue River to the peak of McLoughlin.<ref name=skylakes>Template:Cite web</ref> The wilderness area encompasses more than 200 bodies of water including ponds and lakes, in addition to forests and mountain ridges.<ref name=skylakes/>

Physical geography

The local area has warm, dry summers during the daytime with cool nights,Template:Sfn and snowy winters that impede access to the Sky Lakes Wilderness through July.<ref name=skylakes/> Moisture is limited between June and October barring occasional thunderstorms, which accounts for a very short growing season between ice thawing and drought.<ref name=skylakes/> On average, precipitation does not exceed Template:Convert at medium elevations, reaching Template:Convert at greater heights, most of which consists of snowfall.Template:Sfn

Around the base of the mountain, there are a number of lakes, including the Lake of the Woods and Fourmile Lake. The Upper Klamath Lake, the largest body of freshwater in the state, sits to the east of Mount McLoughlin.Template:Sfn The Summit Lake is a small lake on the northern slope of the volcano between the Rogue River and the Klamath Basin.Template:Sfn The Big Butte Creek, a tributary of the Rogue River, drains the northwestern part of McLoughlin,Template:Sfn while the Little Butte Creek is fed by the southern flanks.Template:Sfn

Ecology

About 20 tree species can be found throughout Mount McLoughlin's surroundings, including Pacific yew at low elevations, mountain hemlock, whitebark pine, and subalpine fir at higher elevations, and lodgepole pine and red fir throughout.<ref name=skylakes/> Other plant species include shrubs, wildflowers, junipers, heather, columbine, kinnikinnick, huckleberry,<ref name=skylakes/> chinquapins, grouse huckleberry, and bearberry.Template:Sfn

Common fauna in the area include chipmunks, deer, elk, American black bears, coyotes, while yellow-bellied marmots, fishers, pikas, and American martens are less common.<ref name=skylakes/> More than 150 bird species live in the Big Butte Creek watershed near McLoughlin.Template:SfnTemplate:Sfn Eagles and hawks can be sighted in the vicinity,<ref name=skylakes/> as can spotted owls.Template:Sfn goshawks like to live beneath the tree canopy in the region.<ref name=skylakes/> Amphibian species like Oregon spotted frogs and Cascades frogs live in certain parts of the watershed.Template:SfnTemplate:Sfn Fish species include Chinook salmon, rainbow trout, Coho salmon, Pacific lamprey,Template:SfnTemplate:SfnTemplate:Sfn and coastal cutthroat trout.Template:SfnTemplate:Sfn

Geology

File:Distant McLoughlin from north.jpg

Mount McLoughlin from the north

Little was known about Mount McLoughlin's geology until the 1970s. Much of what is known today comes from LeRoy Maynard of the center for Volcanology at the University of Oregon. His work established that the volcano was built over three eruptive phases, each with their own eruption types.Template:Sfn James Smith from the United States Geological Survey expanded on Maynard's findings, producing a map of the McLoughlin region.Template:Sfn

McLoughlin is part of the High Cascades,Template:Sfn which trend north–south.Template:Sfn Formed towards the end of the Pleistocene Epoch, these mountains are underlain by more ancient volcanoes that subsided due to parallel north–south faulting in the surrounding region.Template:Sfn Like other Cascade volcanoes, Mount McLoughlin was fed by magma chambers produced by the subduction of the Juan de Fuca tectonic plate under the western edge of the North American tectonic plate.Template:Sfn Within Oregon, plutons, or bodies of intrusive igneous rock that crystallize from magma cooling below the surface of the Earth, lay between Template:Convert northwest of the major High Cascade axis. At McLoughlin, mean displacement rates for the past 16 million years have been Template:Convert each year.Template:Sfn

The volcano shows magnetic high points to the east of its main cone, suggesting that it has normal magnetic polarization that corresponds to an age of less than 700,000 years.<ref name="USGS"/> Other evidence that the volcano is geologically young include its symmetrical shape on the western and southern sides, its well-preserved lava flow deposits, and the absence of soil formation on many of its flow deposits.<ref name="USGS"/>

McLoughlin is a stratovolcano,<ref name="USGS"/> made up of basaltic andesite on top of underlying basaltic andesitic shield volcanoes,Template:Sfn though it is also described as a basaltic-andesite lava cone.<ref name="gvp"/> Much of its central volcanic cone formed within the last 200,000 years, including lava flows on the sides of the mountain that are between 30,000 and 20,000 years old.<ref name=oregonstate/> The volcano has a volume of Template:Convert,<ref name=oregonstate/> and its lava is predominantly basaltic andesite with silicon dioxide content between 53 and 57 percent, though it also has andesite.Template:Sfn

During the last ice age, a large ice cap buried most of the High Cascades, reaching thicknesses in the thousands of feet. Pleistocene glaciers carved out McLoughlin's major volcanic cone, excavating two solidified lava tubes that reached the summit crater. From 25,000 to 12,000 years ago, glaciers on the northern slopes of the volcano combined with an ice cap at the base of the volcano that was about Template:Convert thick. A cirque glacier occupied part of the depression until early in the 20th century.Template:Sfn The volcano displays a lack of snow during the summer season.<ref>Template:Cite news</ref>

Nearby features

File:View from Mount McLoughlin.jpg

View of Pelican Butte and Fourmile Lake from near summit

Two nearby volcanoes closely resemble Mount McLoughlin in composition. Brown Mountain, a shield volcano with a volume of Template:Convert, lies to the southeast, while Pelican Butte, the most prominent shield volcano in the southern Cascades of Oregon, lies to the east.Template:Sfn

Brown Mountain has been dated to between 60,000 and 12,000 years old. It produced basaltic andesite lava flows that have not been heavily eroded, but during Pleistocene glacial advance, ice streams on the volcano ate away at the cinder cone that formed Brown Mountain's summit. This formed a glacial cirque with a bowl shape on the northeastern flank.Template:Sfn

Pelican Butte reaches an elevation of Template:Convert, and it features gradual slopes. Adjacent to Klamath Lake, it has a greater volume than McLoughlin at Template:Convert, and it is made up of basaltic andesite. Like Brown Mountain, Pelican Butte has a cinder cone on the top of its summit, in addition to a glacial cirque and ravine that were excavated on its northeastern side.Template:Sfn These eroded areas exhibit pyroclastic rock in a matrix with lava flows, suggesting that blocky and ʻaʻā lavas formed an outer shell around Pelican Butte's fragmented interior.Template:Sfn Glaciation has also lowered the overall volcano by tens of yards.Template:Sfn

Other volcanoes can be found within the Sky Lakes Wilderness area, including lava flows and mud flows at Big Bunchgrass Butte and Imagination Peak, in addition to more recent eruptive activity at Goosenest Mountain in the northeastern sector.Template:Sfn

Eruptive history

File:UpperKlamathLake.jpg

Mount McLoughlin from the Upper Klamath Lake, showing its summit cone

Mount McLoughlin underwent at least three distinct eruptive phases.<ref name="USGS"/> Early activity at Mount McLoughlin was explosive, and it yielded tephra and pyroclastic rock that built about a third of the overall volume.Template:Sfn These eruptions also yielded lava flows, but they only occurred on the lower flanks. The northwestern flank has volcanic vents that produced lava flows responsible for inundating the Fourbit Creek valley Template:Convert from the base of McLoughlin, which extend up to the Big Butte Springs. Other lava flows from earlier eruptions reach at least Template:Convert from the base of the mountain, a number of which run along the Oregon Route 140 highway. One ʻaʻā stream that filled a river valley for Template:Convert in length moved from an elevation of Template:Convert to Template:Convert, though it was thin, with more than Template:Convert of its length being less than Template:Convert in width.Template:Sfn

A second eruptive stage was characterized by large lava flows, which covered the inner pyroclastic core with basaltic andesite. These thin lava flows formed a shell around the loosely compacted pyroclastic interior.Template:Sfn The third stage of development consisted of floods of blocky lava erupting from below the summit and more fluid lavas erupting from basal fissures, mostly confined to the south slope. Wilámxa Tip<ref name=wilamxa/> and Máalsi Tip<ref name=maalsi/> on McLoughlin's west flank now mark the site of the two major blocky flow vents. There are two smaller vents as well. The entire third stage is thought to have happened after the last Pleistocene glaciers in the area had melted, due to a general lack of weathering and fresh appearance of the solidified lava. The freshest lava flows at Mount McLoughlin occur on the southern and western flanks of the mountain, and they are thought to be between 30,000 and 20,000 years old.Template:Sfn

Future activity

Mount McLoughlin's main volcanic cone has not erupted during the Holocene,Template:Sfn with the last production of lava flows taking place between 30,000 and 20,000 years ago.<ref name=gvp>Template:Cite gvp</ref> The volcano is not currently monitored for activityTemplate:Sfn or deformation.Template:Sfn The closest seismic monitoring stations lie Template:Convert to the south near Mount Shasta and the Medicine Lake Volcano.Template:Sfn

Human history

File:John McLoughlin - Project Gutenberg etext 20110.jpg

Mount McLoughlin got its official name from John McLoughlin (pictured), a factor for the Hudson's Bay Company

McLouglin has served as a landmark to Native American populations and others for thousands of years. Indigenous peoples utilized the area to hunt and gather berries.<ref name=skylakes/> The Takelma people referred to it as "Mal-sr" or "Alwilamchaldis", one of their mythical heroes, and they considered it the home of Tasuune, or the "Acorn Woman", a being that helped their acorns grow every year.Template:Sfn In the culture of the Shasta people, McLoughlin was known as "Makayax"; the Klamath people named the volcano "Walum" and "Kesh yainatat", meaning the home of the "dwarf old woman" that controlled the west wind. McLoughlin was called "Melaiksi" by the Modoc people.Template:Sfn The Little Butte Creek which drains from McLoughlin was called "So-ytanak", translating as "corner" or "rock house", by the Upper Takelma people.Template:Sfn

First detected by an American explorer Peter Skene Ogden in 1827, McLoughlin has a complex name-place history.Template:Sfn Ogden called the volcano "Mt. Sastise" after the Shasta Native Americans that helped him reach the Rogue Valley; this name was later exchanged with Mount Shasta in northern California, then called "Pit Mountain".Template:Sfn To local residents, Mount McLoughlin's English name was Mount Pitt,Template:Sfn though it came to be referred to by other names including Mt. John Quincy Adams, Mt. Clear View, Snowy Butte,Template:Sfn and Mt. Madison,<ref>Template:Cite web</ref> also appearing in maps as Mount Pitt, Mount Simpson, and Mount Jackson.<ref name="USGS"/> Though the volcano was also known as Mount McLoughlin during the 1800s, it was officially renamed in 1905 by the Oregon Legislative Assembly<ref name=histvolcanonames>Template:Cite web</ref> after Dr. John McLoughlin, a factor for the Hudson's Bay Company noted for helping American settlers in the 1830s and 1840s.Template:Sfn An important figure in the local fur trade, McLoughlin was also known as the "Father of Oregon".<ref name=histvolcanonames/> The change from Pitt to McLoughlin was later confirmed by the United States Board on Geographic Names in 1912.<ref>Template:Cite web</ref>

The area around Mount McLoughlin was frequented by fur trappers and explorers, but they did not settle for long stays in the area.<ref name="USGS"/> Settlers living near the surrounding today’s Sky Lakes Wilderness trapped beavers and martens during the winter seasons, hunted, and grazed sheep in warmer months. Stuart Falls and Twin Ponds marked popular spots for picking huckleberries. Trails and fire lookouts were constructed for the Sky Lakes Wilderness area in the early 1900s, with the Pacific Crest Trail expanding into the region during the mid-1970s, superseding the pre-existing Oregon Skyline Trail.<ref name=skylakes/>

Mount McLoughlin's first known ascent took place in 1858, when Joseph Burpee, William Wilkinson, Dr. Greer, Henry Klippel, John S. Love, and Robert Haines, from the city of Jacksonville, reached the summit from the northeast. The event was reported in a letter published by the Jacksonville Democratic Times on May 28, 1897.Template:Sfn In 1896, members of the Mazama mountaineering club including Lottie Reed, Henry Pittock, and Leslie Scott ascended the mountain.<ref name=oreenc/>

As of 1926, Mount McLoughlin's western flank acts as the municipal watershed for Medford, its melted snow feeding the Big Butte Springs near the city. The summer melting of snow forms a shape that is referred to locally as "the angel wings" or "the diving eagle", which local fishers consider a sign of peak fishing opportunities in the mountain's lakes.<ref name=oreenc/>

Recreation

Mount McLoughlin has a Template:Convert hiking trail to its summit,<ref>Template:Cite web</ref> a six hour round-trip which gains about Template:Convert in elevation.Template:Sfn While the route receives moderate to heavy use each year, ascent to the peak is easiest from July through September, when the trailhead is accessible by vehicle and snow is minimal along the path.

The Mt. McLoughlin Trailhead is on Forest Road 3650, Template:Convert north of Oregon Route 140. After about Template:Convert, the Mt. McLoughlin Trail joins the Pacific Crest Trail for half a mile, then passes through a forested area for about Template:Convert before reaching timberline. The last mile of the route travels over blocky lava and rubble, and the trail above the tree line is less clearly delineated. From the summit, Mount Shasta and Crater Lake can be seen.Template:Sfn

During the winter, the climb requires snowshoes, crampons, and ice axes, and is far more challenging than the popular summertime route.<ref>Template:Cite news</ref> The access road from Oregon Route 140 may also be closed due to snow, requiring a longer approach on snowshoes or cross country skis. The mountain can also be skied, which has become more popular in recent years.<ref>Template:Cite news</ref>

See also

• Volcanic Legacy Scenic Byway

Notes

• [a] Template:Note Other sources list the elevation as Template:Convert.Template:Sfn

Sources

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External links

• Template:Cite summitpost