|Three Fingered Jack|
Southwest side of Three Fingered Jack seen from Pacific Crest Trail
|Elevation||7,844 ft (2,391 m) NAVD 88|
|Prominence||756 m (2,480 ft) |
|Location||Jefferson and Linn counties, Oregon, U.S.|
|Topo map||USGS Three Fingered Jack|
|Age of rock||older than 200,000 years|
|Mountain type||Summit, Shield volcano|
|Volcanic arc||Cascade Volcanic Arc|
|First ascent||1923 by E. McNeal and party|
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, the mountain consists mainly of basaltic andesite lava and was heavily glaciated in the past. While other Oregon volcanoes that were heavily glaciated—such as Mount Washington and Mount Thielsen—display eroded volcanic necks, Three Fingered Jack's present summit is a comparatively narrow ridge of loose tephra supported by a dike only 10 feet (3.0 m) thick on a generally north–south axis. Radiating dikes and plugs that support this summit have been exposed by glaciation. The volcano has long been inactive and has been highly eroded.
Diverse flora and fauna can be found surrounding Three Fingered Jack. The area around the volcano was historically inhabited by the Molala people, one of the indigenous groups in the northwestern United States. Not much is known about their culture, other than that the group fished for salmon and collected berries, fruits, obsidian, and dried herbs. The first person of non-indigenous descent to reach the area was David Douglas in 1825, followed by Peter Skene Ogden the following year. The first group to ascend the volcano reached its summit in September 1923. Three Fingered Jack can still be climbed, but when its face becomes foggy, climbers can become disoriented due to the low visibility conditions of climbing the mountain, requiring rescue.
Three Fingered Jack lies in the U.S. state of Oregon, in Linn 2.4 cubic miles (10 km3) and a summit elevation of 7,844 feet (2,391 m), [a] with a proximal topographic relief of 1,300 feet (400 m) and a draping relief of 4,600 feet (1,400 m). [b] Its jagged edifice rises between Mount Jefferson and the Three Sisters volcanic complex. Three Fingered Jack lies within the Mount Jefferson Wilderness and is not accessible by paved road, but can be approached by the Pacific Crest Trail. Located about 20 miles (32 km) northwest of the city of Sisters, it acts as a prominent landmark in the area.and Jefferson counties. It has a volume of
The Mount Jefferson Wilderness lies within the Willamette National Forest and Deschutes National Forest. The wilderness area covers 111,177 acres (449.92 km2), with more than 150 lakes. It also has 190 miles (310 km) of trails, including 40 miles (64 km) of the Pacific Crest National Scenic Trail. Three Fingered Jack and Mount Jefferson are both prominent features of the wilderness area.
During the last major advance of glacial ice in the area during the Wisconsin glaciation, lateral and terminal moraines formed, along with glacial striations, altered vegetation patterns, and lithologies that suggest glacial transport of material. 2.5 acres (1.0 ha), though historically it has reached estimated areas of up to 32 acres (13 ha). It is likely stagnant. During the Little Ice Age, which spanned roughly 1350 to 1850, the glacier produced moraines with heights close to 200 feet (61 m), which are dotted with 1⁄2 to 1 foot (0.15 to 0.30 m) of ash from the Sand Mountain cinder cone chain and 1 foot (0.30 m) of ash from the Blue Lake Crater cinder cone.The sole glacier remaining on the volcano is the unofficially-named Jack glacier, located in a shaded cirque on the northeast side. Because the glacier is covered by tall ridges to the south and west, it resides at an unusually low altitude for the central Oregon Cascades. Jack glacier has an area of
As of 1993, the moraine for Jack glacier dammed a lake with a volume of 940,000 cubic feet (26,500 m3), a surface area of 65,900 square feet (6,120 m2), and a maximum depth of 26 feet (8 m). Though this lake did not appear on United States Geological Survey topographic maps made during the 1920s, its presence was documented by a report in 1937. The lake sits precariously; moraines on the volcano are steep, unstable, and populated with boulders. Before September of 1960, there was a partial breach of this moraine-dammed lake that covered an area of 4,600 square miles (12,000 km2) near the moraine's base. Since 1960, there have been at least two incidents in which moraine-dammed lakes on the volcano have caused floods down the slopes. Local soil is thin, and it has been buried by a layer of weathered, Holocene tephra from Three Fingered Jack, which has a maximum thickness of 3.3 feet (1 m).
Along the volcano and its hiking trails, Douglas fir, Alpine fir, blue spruce, mountain hemlock, and bear grass can be found. 6,500 to 7,000 feet (2,000 to 2,100 m). There are also mountain goats in the surrounding wilderness area.The Cascade parsley fern can be found at Three Fingered Jack between elevations of
Carnivorous animals in the surrounding area include American black bears, coyotes, cougars,red foxes, raccoons, American martens, stoats (also known as ermines), long-tailed weasels, American minks, North American river otters, and bobcats. Deer species include Roosevelt elk, black-tailed deer, and mule deer; insectivores include vagrant shrews, American water shrews, and coast moles. Bats at Jefferson include little brown bats and silver-haired bats, and American pikas and snowshoe hares are also present. Rodents such as yellow-bellied marmots, mountain beavers, yellow-pine chipmunks, Townsend's chipmunks, golden-mantled ground squirrels, western gray squirrels, Douglas squirrels, mountain pocket gophers, North American beavers, deer mice, bushy-tailed woodrats, water voles, Pacific jumping mice, and North American porcupines are present.
Birds nearby include mallards, northern goshawks, sharp-shinned hawks, red-tailed hawks, dusky grouses, grey partridges, killdeers, spotted sandpipers, California gulls, band-tailed pigeons, great horned owls, mountain pygmy owls, common nighthawks, rufous hummingbirds, Northern flickers, pileated woodpeckers, yellow-bellied sapsuckers, hairy woodpeckers, and white-headed woodpeckers.Other bird species found in the area consist of Eurasian three-toed woodpeckers, willow flycatchers, olive-sided flycatchers, tree swallows, Canada jays, Steller's jays, common ravens, Clark's nutcrackers, black-capped chickadees, mountain chickadees, chestnut-backed chickadees, red-breasted nuthatches, pygmy nuthatches, Eurasian treecreepers, American dippers, wrens, American robins, varied thrushes, hermit thrushes, Townsend's solitaires, golden-crowned kinglets, ruby-crowned kinglets, water pipits, blue-headed vireos, western tanagers, Cassin's finches, gray-crowned rosy finches, pine siskins, red crossbills, green-tailed towhees, dark-eyed juncos, white-crowned sparrows, golden-crowned sparrows, fox sparrows, and Lincoln's sparrows. Long-toed salamanders, California giant salamanders, rough-skinned newts, tailed frogs, western toads, Pacific tree frogs, northern red-legged frogs, Oregon spotted frogs, pygmy short-horned lizards, common garter snakes, and northwestern garter snakes make up some of the amphibious and reptilian animals in the vicinity. Roughly half the lakes in the Mount Jefferson Wilderness area contain rainbow trout.
Three Fingered Jack is a shield volcano,[c] and it is part of the group of volcanoes known as Oregon's Matterhorns, whose tall, pinnacle spires resemble the Matterhorn in Switzerland. The volcano, along with Mount Thielsen, Mount Bailey, Diamond Peak, and Mount Washington, had a shorter lifespan than larger volcanoes in the Cascade Range, ceasing eruptive activity more than 100,000 years ago. Three Fingered Jack marks the northernmost point for this group. South of Mount Jefferson, the High Cascades of Oregon consist of a broad ridge produced by shield volcano activity and eruptions from cinder cones. Vents range from deeply eroded complexes to recently active volcanoes, with most of the region mantled by normally polarized rock produced within the past 730,000 years.
The mountain also forms part of a group of more than 30 large shield volcanoes and stratovolcanoes that form a segment of Pleistocene-to-Holocene-epoch volcanic vents that produced mafic lava (rich in magnesium and iron). 34 square miles (88 km2). Between Three Fingered Jack and the North Sister volcano and among recently active basalt lava fields, there is an array of cinder cones encompassing an area of 85 square miles (220 km2).Three Fingered Jack includes several, overlapping cinder cones and composite cones over underlying lava flows from shield volcano activity. These volcanic edifices and their lava flow deposits cover an area of
The major edifice, which consists of light gray, basaltic andesite lava flow deposits, sits 1,000 feet (300 m) to the west of the first tephra cone. Variegated pyroclastic rock is embedded among these flows. Element abundance analysis suggests that lava in the Three Fingered Jack area can be grouped into discrete units based on its source magma chamber, except for the Jorn Lake basalt produced by the underlying shield volcano and basaltic andesite erupted by Three Fingered Jack. Petrological analysis shows high and low pressures for the crystallization of these lava flow deposits, and that basaltic andesite was distinct from basalt due to longer fractionation times.
Though Three Fingered Jack does not have a high-level conduit-filling volcanic plug, its summit sits atop a pyroclastic cone. 350 feet (110 m) to the south of the major cone, and there are secondary craters on the sides, as well as radial dikes and volcanic plugs. Known subfeatures include two shield volcanoes, Maxwell Butte (less eroded than Three Fingered Jack) and Turpentine Peak, which have elevations of 6,230 feet (1,899 m) and 5,794 feet (1,766 m), respectively. There are six additional known volcanic cones: Duffy Butte, at an elevation of 5,837 feet (1,779 m); Hogg Rock (a tuya), at an elevation of 5,050 feet (1,540 m); Marion Mountain, at an elevation of 5,351 feet (1,631 m); Red Butte, with an elevation of 5,814 feet (1,772 m); and Marion Peak and Saddle Mountain, which do not have elevations listed. Other shield volcanoes and cinder cones that were active during the Pleistocene epoch occur to the northwest and southwest.Another cone lies
The volcano has a long ridge that trends from north to south. It is highly eroded; 10 feet (3.0 m). Erosion has been so extensive that climbers claim that the summit moves in the wind. During the Pleistocene epoch, glaciers exposed its inner contents, providing evidence for its eruptive history. Though it has not been dated by radiometric approaches, the volcano is likely between 500,000 and 250,000 years old, and has been carved out by at least three glacial periods.shaped like a sawtooth, it consists of tephra deposits supported by a vertical dike with a thickness of
Three Fingered Jack shows a similar eruptive history to many High Cascade volcanoes.Activity began with the formation of a pyroclastic cone over shield volcanoes. Later eruptions formed a main volcanic cone from lava flows and more pyroclastic rock. There are dikes that radiate from a micronorite plug, which deformed tephra in the surrounding strata. The northern and southern flanks of Three Fingered Jack feature lava flows made of olivine and augite basalt.
Three Fingered Jack is estimated to be between 500,000 and 250,000 years old. 3 feet (0.91 m). Secondary volcanic craters produced lava flows and pyroclastic material, which traveled both north and south of the volcano. Cone-building eruptions ceased before the Pleistocene epoch's glacial period, allowing the expanded glacial cover to remove most of the cone, especially on the eastern and northeastern sides.It underwent more explosive eruptions as its eruptive history progressed, generating large amounts of tephra, which created a loose, unconsolidated summit and upper cone. Lava flows near the summit have an average thickness of
During the ongoing Holocene epoch, there has been volcanic activity between the Three Sisters volcanoes and Three Fingered Jack. Such eruptive episodes have produced tephra and lava flows that cover several hundred square kilometers in the region. These eruptions occurred after the climactic eruption of Mount Mazama, which took place roughly 6,600 years ago.
The surrounding area has traditionally been inhabited by Molala people, one of the indigenous groups in the northwestern United States. The group fished for salmon, collecting berries, fruits, obsidian, and dried herbs. Their culture was not well documented.The first person of non-indigenous descent to reach the area was David Douglas in 1825, followed by Peter Skene Ogden the following year.
Sources disagree about the affiliation of the mountain's first ascenders, some calling them "the Boys from Bend," 3, 1923.others saying they were members of the Mazamas mountaineering club. Nonetheless, a source written by one of these first ascenders clearly states who was in the party and when they climbed. Ervin McNeal, Phil Philbrook, Armin Furrer, Wilbur Watkins, Leo Harryman, and Ronald Sellars were the first to ascend Three Fingered Jack on September
The origins of Three Fingered Jack's name remain unclear.One account claims that the volcano received its name from Joaquin Murrieta, a gold miner and vaquero during the California Gold Rush also known as Three Fingered Jack. Others allege that the volcano was named after a trapper with less than five fingers on one of his hands.
Three Fingered Jack's surrounding area can be hiked, offering views of the volcano. The Canyon Creek Meadows hiking trail begins at Jack Lake, progresses through the Mount Jefferson Wilderness, and runs for about 4.5 miles (7.2 km). It has an elevation gain of 400 feet (120 m), and can be hiked by children and families. An additional, connected hiking trail runs for another 3 miles (4.8 km) up the rocky glacial washout plain adjacent to the volcano, becoming steeper as it approaches Three Fingered Jack and gaining 1,400 feet (430 m) in elevation. The base can also be reached on Pacific Crest Trail 2000, which runs for 11.6 miles (18.7 km) round trip and offers views of the volcano and its summit lake. Moreover, the Three Fingered Jack loop trail runs for 20.5 miles (33.0 km) around the volcano, gaining 3,300 feet (1,000 m) in elevation.
When Three Fingered Jack's face becomes foggy, climbers have become disoriented due to the low visibility conditions of climbing the mountain, requiring rescue.
Mount Bachelor, formerly named Bachelor Butte, is a stratovolcano atop a shield volcano in the Cascade Volcanic Arc and the Cascade Range of central Oregon. Named Mount Bachelor because it "stands apart" from the nearby Three Sisters, it lies in the eastern segment of the central portion of the High Cascades, the eastern segment of the Cascade Range. The volcano lies at the northern end of the 15-mile (24 km) long Mount Bachelor Volcanic Chain, which underwent four major eruptive episodes during the Pleistocene and the Holocene. The United States Geological Survey considers Mount Bachelor a moderate threat, but Bachelor poses little threat of becoming an active volcano in the near future. It remains unclear whether the volcano is extinct or just inactive.
Lassen Peak, commonly referred to as Mount Lassen, is the southernmost active volcano in the Cascade Range of the Western United States. Located in the Shasta Cascade region of Northern California, it is part of the Cascade Volcanic Arc, which stretches from southwestern British Columbia to northern California. Lassen Peak reaches an elevation of 10,457 feet (3,187 m), standing above the northern Sacramento Valley. It supports many flora and fauna among its diverse habitats, which are subject to frequent snowfall and reach high elevations.
Mount Jefferson is a stratovolcano in the Cascade Volcanic Arc, part of the Cascade Range in the U.S. state of Oregon. The second highest mountain in Oregon, it is situated within Linn County, Jefferson County, and Marion County and forms part of the Mount Jefferson Wilderness. Due to the ruggedness of its surroundings, the mountain is one of the hardest volcanoes to reach in the Cascades. It is also a popular tourist destination despite its remoteness, with recreational activities including hiking, backpacking, mountaineering, and photography. Vegetation at Mount Jefferson is dominated by Douglas fir, silver fir, mountain hemlock, ponderosa pine, lodgepole pine, and several cedar species. Carnivores, insectivores, bats, rodents, deer, birds, and various other species inhabit the area.
Mount Thielsen, or Big Cowhorn, is an extinct shield volcano 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, a reserve for recreational activities such as skiing and hiking.
Mount Mazama is a complex volcano in the state of Oregon, United States, in a segment of the Cascade Volcanic Arc and Cascade Range. Most of the mountain collapsed following a major eruption approximately 7,700 years ago. The volcano is in Klamath County, in the southern Cascades, 60 miles (97 km) north of the Oregon-California border. Its collapse formed a caldera that holds Crater Lake. The mountain is in Crater Lake National Park. Mount Mazama originally had an elevation of 12,000 feet (3,700 m), but following its climactic eruption this was reduced to 8,157 feet (2,486 m). Crater Lake is 1,943 feet (592 m) deep, the deepest freshwater body in the US and the second deepest in North America after Great Slave Lake in Canada.
Mount Washington is a deeply eroded volcano in the Cascade Range of Oregon. It lies within Deschutes and Linn counties and is surrounded by the Mount Washington Wilderness area.
Belknap Crater is a shield volcano in the Cascade Range in the U.S. state of Oregon. Located in Linn County, it is associated with lava fields and numerous subfeatures including the Little Belknap and South Belknap volcanic cones. It lies north of McKenzie Pass and forms part of the Mount Washington Wilderness. Belknap is not forested and most of its lava flows are not vegetated, though there is some wildlife in the area around the volcano, as well as a number of tree molds formed by its eruptive activity.
Mount McLoughlin is a steep-sided stratovolcano, or composite volcano, in the Cascade Range of southern Oregon and within 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 Crater Lake lies to the north-northeast. 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 American populations for thousands of years.
Indian Heaven is a volcanic field in Skamania County in the state of Washington, in the United States. Midway between Mount St. Helens and Mount Adams, the field dates from the Pleistocene to the early Holocene epoch. It trends north to south and is dominated by six small shield volcanoes; these shields are topped by small spatter and cinder cones, and the field includes a number of subglacial volcanoes and tuyas. The northernmost peak in the field is Sawtooth Mountain and the southernmost is Red Mountain; its highest point is Lemei Rock at an elevation of 5,925 feet (1,806 m).
Broken Top is a glacially eroded 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 peaks, the volcano, residing within the Three Sisters Wilderness, is 20 miles (32 km) west of Bend, Oregon in Deschutes County. Eruptive activity stopped roughly 100,000 years ago, and currently, erosion by glaciers has reduced the volcano's cone to where its contents are exposed. There are two named glaciers on the peak, Bend and Crook Glacier.
The Three Sisters are closely spaced volcanic peaks in the U.S. state of Oregon. They are part of the Cascade Volcanic Arc, a segment of the Cascade Range in western North America extending from southern British Columbia through Washington and Oregon to Northern California. Each more than 10,000 feet (3,000 m) in elevation, they are the third-, fourth- and fifth-highest peaks in Oregon. Located in the Three Sisters Wilderness at the boundary of Lane and Deschutes counties and the Willamette and Deschutes national forests, they are about 10 miles (16 km) south of the nearest town, Sisters. Diverse species of flora and fauna inhabit the area, which is subject to frequent snowfall, occasional rain, and extreme temperature variation between seasons. The mountains, particularly South Sister, are popular destinations for climbing and scrambling.
Black Butte is an extinct stratovolcano in the U.S. state of Oregon. Located in Jefferson County, it is part of Deschutes National Forest. Black Butte forms part of the Cascade volcanic arc. The butte lies just south of the Metolius Springs, which merge to form the headwaters of the Metolius River. The Metolius River's basin sustains a wide array of plant life, large and small mammals, and more than 80 bird species.
Diamond Peak is a volcano in Klamath and Lane counties of central Oregon in the United States. It is a shield volcano, though it might also be considered a modest stratocone. Diamond Peak forms part of the Cascade Volcanic Arc, a segment of the Cascade Range in western North America extending from southern British Columbia through Oregon to Northern California. Reaching an elevation of 8,748 feet (2,666 m), the mountain is located near Willamette Pass in the Diamond Peak Wilderness within the Deschutes and Willamette national forests. Surrounded by coniferous forest and visible in the skyline from foothills near Eugene, Diamond Peak offers a few climbing routes and can be scrambled.
West Crater is a small lava dome with associated lava flows in southern Washington, United States. Located in Skamania County, it rises to an elevation of 4,131 feet (1,259 m), and forms part of the Cascade Volcanic Arc. It is also part of the Marble Mountain-Trout Creek Hill volcanic field, a little-known Quaternary volcanic field in the southern Cascades of Washington state. The area can be hiked, and can be accessed by roads in the Gifford Pinchot National Forest.
Olallie Butte is a steep-sided shield volcano in the Cascade Range of the northern part of the U.S. state of Oregon. It is the largest volcano and highest point in the 50-mile (80 km) distance between Mount Hood and Mount Jefferson. Located just outside the Olallie Scenic Area, it is surrounded by more than 200 lakes and ponds fed by runoff, precipitation, and underground seepage, which are popular spots for fishing, boating, and swimming. The butte forms a prominent feature in the Mount Jefferson region and is usually covered with snow during the winter and spring seasons.
Hoodoo Butte is a cinder cone butte in the Cascade Range of northern Oregon, located near Santiam Pass. Immediately to the east lies Hayrick Butte, a prime example of a tuya; the two mountains' names were likely mistaken for each other, but stuck with them over time. The area has been subjected to a number of historic fires. Hoodoo is sometimes considered a subfeature of the Mount Washington shield volcano, and it forms part of the Sisters Reach, which extends from South Cinder Peak to Crane Prairie Reservoir, running for 56 miles (90 km). This region has a high vent density, with many mafic volcanoes of Pleistocene to Holocene age, such as Hoodoo. While Hoodoo has an intact summit crater that was blocked from erosion by glaciers, it has an irregular topography, giving it an open appearance.
Hayrick Butte is a tuya, a type of subglacial volcano, in Linn County, Oregon. Located in the Willamette National Forest near Santiam Pass, it lies adjacent to the cinder cone Hoodoo Butte, which has a ski area. Hayrick Butte likely formed when lava erupted underneath an overlying glacier or ice sheet, producing the flat top with near-vertical walls along the ice-contact margin as the lava cooled and hardened. Hayrick Butte has a nearly flat plateau about 0.5 miles (0.80 km) across and steep walls rising about 700 feet (0.21 km) above its surroundings. A cartographer accidentally switched the names for nearby Hoodoo Butte and Hayrick Butte; the word "hoodoo" usually refers to rock piles and pinnacles like those observed at Hayrick Butte.
Hogg Rock is a tuya volcano and lava dome in the Cascade Range of northern Oregon, located close to Santiam Pass. Produced by magma with an intermediate andesite composition, it has steep slopes and thick glassy margins. Hogg Rock exhibits normal magnetic polarity and is probably about 80,000 years old.
Blue Lake Crater is a maar, or a broad, low-relief volcanic crater, in the U.S. state of Oregon. Located in Jefferson County, it consists of three overlapping craters, which hold Blue Lake. The drainage basin for Blue Lake has very steep, forested slopes and is mostly part of the explosion crater left by the volcano's eruption. The volcano lies within the Metolius River basin, which supports a wide array of plant life, large and small mammals, and more than 80 bird species. In 2009, Governor of Oregon Ted Kulongoski signed a bill designating the Metolius River basin as an area of critical concern, preventing large-scale development on the land and protecting its wildlife.
The Sand Mountain Volcanic Field is a volcanic field in the upper McKenzie River watershed, located in the United States in Oregon. Part of the Cascade Volcanic Arc, it lies southwest of Mount Jefferson and northwest of Belknap Crater and Mount Washington. Its highest elevation is 5,463 feet (1,665 m).