110-671: Hoodoo Mountain , sometimes referred to as Hoodoo Volcano , is a potentially active stratovolcano in the Northern Interior of British Columbia , Canada. It is located 25 kilometres (16 miles) northeast of the Alaska –British Columbia border on the north side of the Iskut River opposite of the mouth of the Craig River . With a summit elevation of 1,850 metres (6,070 feet) and a topographic prominence of 900 metres (3,000 feet), Hoodoo Mountain
220-422: A home range averaging about 14 hectares (35 acres). Each colony includes a single, dominant, adult male, up to three adult females, sometimes with a subordinate adult male, and a number of young and subadults up to two years of age. The marmots hibernate seven to eight months a year in burrows they excavate in the soil, often among or under boulders. Each colony typically maintains a single hibernaculum and
330-517: A 17 to 25 cm (6.7 to 9.8 in) tail. The species is sexually dimorphic , with males being significantly larger than females in most subspecies. Because of their long winter hibernation , during which they survive on fat reserves, the weight of the animals varies considerably over the course of the year, from an average of 3.75 kg (8.3 lb) in May to around 7 kg (15 lb) in September, for
440-747: A 4-inch thick ash layer can weigh 120-200 pounds and can get twice as heavy when wet. Wet ash also poses a risk to electronics due to its conductive nature. Dense clouds of hot volcanic ash can be expelled due to the collapse of an eruptive column , or laterally due to the partial collapse of a volcanic edifice or lava dome during explosive eruptions . These clouds are known as pyroclastic surges and in addition to ash , they contain hot lava , pumice , rock , and volcanic gas . Pyroclastic surges flow at speeds over 50 mph and are at temperatures between 200 °C – 700 °C. These surges can cause major damage to property and people in their path. Lava flows from stratovolcanoes are generally not
550-490: A J-shaped cliff called The Hook. Like The Wall to the southwest, The Hook is the front of an ice-marginal lava flow. Slide Canyon consists of a large chasm that cuts deeply into the southwestern side of Hoodoo Mountain. It is intruded by several dikes, including the one that fed The Monument. Pumice Point on the northwestern side of Hoodoo Mountain contains highly vesicular, lapilli to block -sized fragments of "woody pumice " up to 15 centimetres (5.9 inches) long. Extending from
660-492: A caldera or large crater beneath the ice cap. Instead, the underlying topography was shown to be characteristic of an inverted and very shallow saucer . The use of radars to penetrate the ice cap and to assess the subglacial topography proved to be instrumental for studying other glaciated volcanoes in the American Cordillera and elsewhere. Personnel involved in the 1997 expedition were Catherine Hickson and Mark Stasiuk of
770-474: A capping sequence of subaerial lavas typical of tuyas. It does, however, coincide with Souther's original use of the term tuya in that its overall geomorphology has been strongly influenced by interaction between ice and lava. The first detailed summary of the Quaternary stratigraphy and petrology of Hoodoo Mountain was compiled in 1997 by American geologist Ben Edwards who produced a detailed geologic map of
880-926: A depth of about 3.5 metres (11 ft). A colony may have up to 9 regular sleeping burrows, in addition to the larger hibernaculum. Many forms of social behaviour have been observed among hoary marmots, including play fighting, wrestling, social grooming, and nose-to-nose touching. Such activity becomes particularly frequent as hibernation approaches. Interactions with individuals from other colonies are less common, and usually hostile, with females chasing away intruders. Hoary marmots are also vocal animals, with at least seven distinct types of calls, including chirps, whistles, growls, and whining sounds. Many of these calls are used as alarms, alerting other animals to potential predators. They also communicate using scent, both by defecation, and by marking rocks or plants using scent glands on their cheeks. Hoary marmots frequently sun themselves on rocks, spending as much as 44% of their time in
990-403: A diameter of 3–4 kilometres (1.9–2.5 miles), attaining a minimum volume of 3.2 cubic kilometres (0.77 cubic miles). Its circular shape and higher elevation have made it relatively stable to climate change , having undergone minor retreat and thinning only at its very edges. It therefore maintains at least partial snow cover during all months of the year. At the north–central end of the ice cap lies
1100-431: A difficult struggle to maintain their channels." An ice-filled crater was speculated by Kerr to underlie the summit ice cap. In 1991, Canadian volcanologist Jack Souther provided a short account of the geomorphology of Hoodoo Mountain as well as some age-constraints from preliminary K–Ar dating . Hoodoo Mountain's relatively flat-topped geomorphology led Souther to refer to it as a tuya , even though its summit lacks
1210-474: A fast moving mudflow . Lahars are typically about 60% sediment and 40% water. Depending on the abundance of volcanic debris the lahar can be fluid or thick like concrete. Lahars have the strength and speed to flatten structures and cause great bodily harm, gaining speeds up to dozens of kilometers per hour. In the 1985 eruption of Nevado del Ruiz in Colombia , Pyroclastic surges melted snow and ice atop
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#17328525673331320-966: A few hundred years ago. The cause of volcanic activity in the Northern Cordilleran Volcanic Province is thought to be due to rifting of the North American Cordillera driven by changes in relative plate motion between the North American and Pacific plates. Hoodoo Mountain is part of a subdivision of the NCVP called the Stikine Subprovince. This subprovince, confined to the Stikine region of northwestern British Columbia, includes three other volcanic centres: Heart Peaks , Level Mountain and Mount Edziza . The four volcanic centres differ petrologically and/or volumetrically from
1430-515: A final intermediate composition . When the magma nears the top surface, it pools in a magma chamber within the crust below the stratovolcano. The processes that trigger the final eruption remain a question for further research. Possible mechanisms include: These internal triggers may be modified by external triggers such as sector collapse , earthquakes , or interactions with groundwater . Some of these triggers operate only under limited conditions. For example, sector collapse (where part of
1540-642: A fully grown adult. A few fall adult males can commonly range up to a weight of 10 kg (22 lb). The record sized autumn male specimen attained a mass of nearly 13.5 kg (30 lb), possibly the largest size known for any marmot. Going on its average size relative to other marmot species, it is slightly smaller on average than the Olympic marmot , similar in size to the Vancouver Island marmot and broadly overlaps in size with several lesser-known Asian marmot species as well. The word "hoary" refers to
1650-497: A glaciated environment. As lava travelled down slope, the lava came into contact with glacial ice that completely surrounded Hoodoo Mountain and cooled very quickly, forming a barrier around the entire volcano. This is demonstrated by the glassy texture of the lava and columnar jointing , which indicate fairly quick cooling of an erupted lava flow. The lava cooled, pooled and as the glacial ice receded, it left behind massive lava cliffs. The south–central side of Hoodoo Mountain contains
1760-482: A large depression called Long Valley. This feature, having formed by glacial erosion, contains a series of domes with adjacent lava spines . Pointer Ridge on the north–central side of Hoodoo Mountain consists of pyroclastic rocks that form a 200-metre-thick (660-foot) stratigraphic unit . The Wall, a more than 200-metre-high (660-foot) cliff at the western base of Hoodoo Mountain, forms the front of an ice-marginal lava flow that displays columnar jointing. The Monument on
1870-479: A number of smaller burrows, used for sleeping and refuge from predators. The refuge burrows are the simplest and most numerous type, consisting of a single bolt hole 1 to 2 metres (3 ft 3 in to 6 ft 7 in) deep. Each colony digs an average of five such burrows a year, and a mature colony may have over a hundred. Sleeping burrows and hibernacula are larger and more complex, with multiple entrances, deep chambers lined with plant material, and stretching to
1980-412: A period of eruptions showing no apparent evidence for ice interaction, subglacial eruptions resumed between 54,000–30,000 years ago, signalling the build-up of regional ice levels. This fifth eruptive period occurred in two stages. The first stage took place between 54,000–40,000 years ago when the overriding glacial ice was possibly more than 2 kilometres (1.2 miles) thick. Isolated vents produced
2090-758: A prominent nunatak called The Horn or Horn Nunatak which consists of pyroclastic rock surrounding a core of lava. Hoodoo Mountain is part of the Northern Cordilleran Volcanic Province (NCVP), a broad area of shield volcanoes , lava domes , cinder cones and stratovolcanoes extending from northwestern British Columbia northwards through Yukon into easternmost Alaska . The dominant rocks comprising these volcanoes are alkali basalts and hawaiites , but nephelinite , basanite and peralkaline phonolite , trachyte and comendite are locally abundant. These rocks were deposited by volcanic eruptions from 20 million years ago to as recently as
2200-739: A result of intraplate volcanism on oceanic islands far from plate boundaries. Examples are Teide in the Canary Islands , and Pico do Fogo in Cape Verde . Stratovolcanoes in the East African Rift include Ol Doinyo Lengai in Tanzania, and Longonot in Kenya. Subduction zone volcanoes form when hydrous minerals are pulled down into the mantle on the slab. These hydrous minerals, such as chlorite and serpentine , release their water into
2310-501: A roughly 30-to-50-metre-thick (98-to-164-foot) unit of lava flows, lava lobes and breccia on the north–central, northwestern and western flanks of Hoodoo Mountain. The sixth and final eruptive period began 10,000–9,000 years ago with the eruption of 5-to-10-metre-thick (16-to-33-foot) phonolitic lava flows from vents near the summit. They travelled down the north–central, northwestern, southeastern and southwestern flanks of Hoodoo Mountain without encountering any glacial ice, suggesting
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#17328525673332420-562: A significant portion of the Mesozoic basement. Intruding the basement rocks are 1.8-million-year-old trachyandesite dikes , which represent the earliest known manifestations of Quaternary magmatism in the Iskut region. Hoodoo Mountain has been described as "one of the most magnificent and interesting mountains in northern British Columbia". This is because it has a different lithological and topographical structure than most glaciated mountains in
2530-461: A significant threat to humans or animals because the highly viscous lava moves slowly enough for everyone to evacuate. Most deaths attributed to lava are due to related causes such as explosions and asphyxiation from toxic gas . Lava flows can bury homes and farms in thick volcanic rock which greatly reduces property value. However, not all stratovolcanoes erupt viscous and sticky lava . Nyiragongo , near Lake Kivu in central Africa ,
2640-490: A subglacial volcano due to much of the mountain having formed subglacially in the last 85,000 years. Its involvement with glaciation has resulted in several interactions with glacial ice as much as 2 kilometres (1.2 miles) thick, affording multiple examples of glaciovolcanic processes. This includes the formation of ice-marginal lava flows and the interlayering of glacial till with volcanic deposits. Hoodoo Mountain's constant struggle with surrounding and overlying ice
2750-671: A warning for a large eruption; the system might detect activity only once the volcano has started erupting. If Hoodoo Mountain were to erupt, mechanisms exist to orchestrate relief efforts. The Interagency Volcanic Event Notification Plan was created to outline the notification procedure of some of the main agencies that would respond to an erupting volcano in Canada, an eruption close to the Canada–United States border or any eruption that would affect Canada. The volcanic deposits at Hoodoo Mountain were briefly described in 1948 by F. A. Kerr of
2860-415: A wide variety of volcanic deposits extensively distributed around the entire summit region. This includes subglacially erupted lava lobes and domes, as well as ice-chilled breccia and hyaloclastite, which form a 400-metre-thick (1,300-foot) volcanic unit. The second stage between 40,000–30,000 years ago was characterized by fissure -fed eruptions beneath relatively thin ice cover. These eruptions produced
2970-529: Is Bob Quinn Lake about 60 kilometres (37 miles) northeast of Hoodoo Mountain along the Stewart–Cassiar Highway . From there the mountain can be reached by charter helicopter or by trekking across mountainous terrain with extreme difficulty. Alternatively, fixed-wing aircraft landings can be made on the Bronson Creek runway immediately south of Hoodoo Mountain. The mountain can also be approached from
3080-532: Is Mount Edziza at 2,786 metres (9,140 feet), followed by Level Mountain at 2,164 metres (7,100 feet), Heart Peaks at 2,012 metres (6,601 feet) and Hoodoo Mountain at 1,850 metres (6,070 feet). Hoodoo Mountain is one of ten volcanoes composing the Iskut volcanic field . This is a group of NCVP volcanoes scattered along the Iskut River and its main tributaries . They consist of both subaerial and glaciovolcanic deposits,
3190-523: Is a species of marmot that inhabits the mountains of northwest North America . Hoary marmots live near the tree line on slopes with grasses and forbs to eat and rocky areas for cover. It is the largest North American ground squirrel and is often nicknamed "the whistler" for its high-pitched warning issued to alert other members of the colony to possible danger. The animals are sometimes called "whistle pigs". Whistler, British Columbia , originally London Mountain because of its heavy fogs and rain,
3300-527: Is a passive release of gas during periods of dormancy. As per the above examples, while eruptions like Mount Unzen have caused deaths and local damage, the impact of the June 1991 eruption of Mount Pinatubo was seen globally. The eruptive columns reached heights of 40 km and dumped 17 megatons of SO 2 into the lower stratosphere . The aerosols that formed from the sulfur dioxide (SO 2 ), carbon dioxide (CO 2 ), and other gases dispersed around
3410-577: Is a roughly 350-metre-long (1,150-foot) and 100-metre-wide (330-foot) lake which may occupy a previously drained depression . The western side of the glacier contains a small possibly drained ice-marginal lake. Twin Glacier surrounds the northwestern base of Hoodoo Mountain and is the largest of the two valley glaciers. It is the source of the Twin River which also flows south into the Iskut River. Several changes have taken place at this double-lobed glacier since
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3520-437: Is attested by its nearly flat summit, which attains an elevation of 1,850 metres (6,070 feet). Lava flows from Hoodoo Mountain partially bury Little Bear Mountain, a much smaller and older basaltic volcano immediately to the north. Both volcanoes are underlain by plutonic rocks and metamorphosed volcanic and sedimentary rocks of Stikinia . These basement rocks are of Paleozoic – Mesozoic age; pyroxene syenite composes
3630-651: Is intermediate between fully coastal maritime and continental climates. Moist air from the Pacific Ocean brings intense precipitation over the region while simultaneously allowing cold Arctic air to pass down through the Portland Canal into the Dixon Entrance where it flows into British Columbia's North Coast . Therefore, the regional climate is mostly cool and wet with snowpacks and heavy precipitation. About 500 millimetres (20 inches) of precipitation falls during
3740-610: Is long, slightly flattened, and covered with dense fur. Apart from the larger size of the males, both sexes have a similar appearance. Females have five pairs of teats , running from the pectoral to the inguinal regions. The hoary marmot predominantly inhabits mountainous alpine environments to 2,500 metres (8,200 ft) elevation, although coastal population also occur at or near sea level in British Columbia and Alaska. Hoary marmots occur from southern Washington and central Idaho north, and are found through much of Alaska south of
3850-404: Is no human population within 30 kilometres (19 miles) of Hoodoo Mountain but 2,330 people live within 100 kilometres (62 miles). Forests of this ecosection grow on the lower slopes of Hoodoo Mountain except for its northeastern flank where rock and ice are dominant. Much of this forest cover lies at elevations below 900 metres (3,000 feet). Hoodoo Mountain has a maritime glacial climate that
3960-476: Is often felsic , having high to intermediate levels of silica (as in rhyolite , dacite , or andesite ), with lesser amounts of less viscous mafic magma . Extensive felsic lava flows are uncommon, but can travel as far as 8 km (5 mi). The term composite volcano is used because the strata are usually mixed and uneven instead of neat layers. They are among the most common types of volcanoes; more than 700 stratovolcanoes have erupted lava during
4070-533: Is one of many prominent peaks within the Boundary Ranges of the Coast Mountains . Its flat-topped summit is covered by an ice cap more than 100 metres (330 feet) thick and at least 3 kilometres (1.9 miles) in diameter. Two valley glaciers surrounding the northwestern and northeastern sides of the mountain have retreated significantly over the last hundred years. They both originate from a large icefield to
4180-400: Is one of the largest peralkaline volcanoes in the NCVP. It is a stratovolcano composed primarily of peralkaline phonolite and trachyte lava flows and hyaloclastites, although some pyroclastic rocks are also present. Its peralkalinity is unique among other volcanoes in the Iskut volcanic field, which range in composition from alkali basalt to hawaiite . Hoodoo Mountain has also been designated as
4290-451: Is the most famous example of a hazardous stratovolcano eruption. It completely smothered the nearby ancient cities of Pompeii and Herculaneum with thick deposits of pyroclastic surges and pumice ranging from 6–7 meters deep. Pompeii had 10,000-20,000 inhabitants at the time of eruption. Mount Vesuvius is recognized as one of the most dangerous of the world's volcanoes, due to its capacity for powerful explosive eruptions coupled with
4400-450: Is typically between 700 and 1,200 °C (1,300-2,200 °F). Volcanic bombs are masses of unconsolidated rock and lava that are ejected during an eruption. Volcanic bombs are classified as larger than 64mm (2.5 inches). Anything below 64mm is classified as a volcanic block . When erupted Bombs are still molten and partially cool and solidify on their descent. They can form ribbon or oval shapes that can also flatten on impact with
4510-534: Is unknown but its stratigraphic position suggests it is about 7,000–8,000 calendar years old. No volcanic deposits of this age are known at Hoodoo Mountain but there may be younger deposits that are completely covered by the summit ice cap. Hoodoo Mountain is a dormant but potentially active volcano, having experienced at least eight seismic events since 1985. Hazards stemming from renewed volcanism are lava flows and flooding, as well as fallout from explosive eruptions. Lava flows generated by effusive eruptions could dam
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4620-410: Is unlikely due to the lack of a caldera to fill with meltwater . Explosive eruptions could produce significant pyroclastic fall to disrupt local mining operations, as well as airborne ash which would potentially disrupt air traffic to and from the mining camps . Air traffic between Canada, Alaska and Asia would likely be disrupted by high eruption columns due to the presence of major airways near
4730-403: Is very dangerous because its magma has an unusually low silica content , making it much less viscous than other stratovolcanoes. Low viscosity lava can generate massive lava fountains , while lava of thicker viscosity can solidify within the vent, creating a volcanic plug . Volcanic plugs can trap gas and create pressure in the magma chamber, resulting in violent eruptions. Lava
4840-521: Is very easily broken. These observations have been taken to indicate a very recent origin, possibly not more than a few hundred years old. Hoodoo Mountain is a possible source of the Finlay tephras . These are two 5-to-10-millimetre-thick (0.20-to-0.39-inch) phonolitic to trachytic tephra layers in the Dease Lake and Finlay River areas. Radiocarbon dating of terrestrial plant macrofossils directly overlying
4950-480: The Canadian Cordillera . In contrast to its rugged counterparts, Hoodoo Mountain is symmetrical and circular in form. It has a basal diameter of around 6 kilometres (3.7 miles), a volume of 17.3 cubic kilometres (4.2 cubic miles) and a topographic prominence of 900 metres (3,000 feet), making it the smallest of the four volcanoes composing the Stikine Subprovince. Hoodoos , pillar-like rock formations after which
5060-461: The Geological Survey of Canada (GSC) while studying the regional geology along the southern part of the Iskut River. According to Kerr, "the volcano erupted in the centre of an old valley that must have drained to the Iskut about 3 miles above the present Hoodoo River [...] Successive outflows from the volcano repeatedly disrupted the drainage, so that the flanking streams and glaciers have had
5170-800: The Holocene Epoch (the last 11,700 years), and many older, now extinct, stratovolcanoes erupted lava as far back as Archean times. Stratovolcanoes are typically found in subduction zones but they also occur in other geological settings. Two examples of stratovolcanoes famous for catastrophic eruptions are Krakatoa in Indonesia (which erupted in 1883 claiming 36,000 lives) and Mount Vesuvius in Italy (which erupted in 79 A.D killing an estimated 2,000 people). In modern times, Mount St. Helens (1980) in Washington State , US, and Mount Pinatubo (1991) in
5280-573: The Philippines have erupted catastrophically, but with fewer deaths. Stratovolcanoes are common at subduction zones , forming chains and clusters along plate tectonic boundaries where an oceanic crust plate is drawn under a continental crust plate (continental arc volcanism, e.g. Cascade Range , Andes , Campania ) or another oceanic crust plate ( island arc volcanism, e.g. Japan , Philippines , Aleutian Islands ). Stratovolcanoes also occur in some other geological settings, for example as
5390-689: The Pleistocene . Both glaciers originate from the Andrei Icefield centered 16 kilometres (9.9 miles) northeast of Hoodoo Mountain. This large glacial field is informally named after the son of Olav Mokievsky-Zubok, a glaciologist who carried out significant glaciological work in the Coast Mountains from the 1960s to the 1970s. The summit of Hoodoo Mountain contains an ice cap that persists at elevations greater than 1,600 metres (5,200 feet). It varies from 100 to 150 metres (330 to 490 feet) thick and has
5500-565: The Yukon River . They live above the tree line , at elevations from sea level to 2,500 metres (8,200 ft), depending on latitude, in rocky terrain or alpine meadows dominated by grasses, sedges, herbs, and Krummholz forest patches. Range maps often erroneously depict hoary marmots occurring north of the Yukon River in Alaska, this region is occupied by the Alaska marmot ( M. broweri ) and not
5610-891: The magma is too viscous to allow easy escape of volcanic gases . As a consequence, the tremendous internal pressures of the trapped volcanic gases remain and intermingle in the pasty magma . Following the breaching of the vent and the opening of the crater, the magma degasses explosively. The magma and gases blast out with high speed and full force. Since 1600 CE , nearly 300,000 people have been killed by volcanic eruptions . Most deaths were caused by pyroclastic flows and lahars , deadly hazards that often accompany explosive eruptions of subduction-zone stratovolcanoes. Pyroclastic flows are swift, avalanche-like, ground-sweeping, incandescent mixtures of hot volcanic debris, fine ash , fragmented lava , and superheated gases that can travel at speeds over 150 km/h (90 mph). Around 30,000 people were killed by pyroclastic flows during
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#17328525673335720-443: The mantle which decreases its melting point by 60 to 100 °C. The release of water from hydrated minerals is termed " dewatering ", and occurs at specific pressures and temperatures for each mineral, as the plate descends to greater depths. This allows the mantle to partially melt and generate magma . This is called flux melting . The magma then rises through the crust , incorporating silica-rich crustal rock, leading to
5830-607: The 1902 eruption of Mount Pelée on the island of Martinique in the Caribbean . During March and April 1982, El Chichón in the State of Chiapas in southeastern Mexico , erupted 3 times, causing the worst volcanic disaster in that country's history and killied more than 2,000 people in pyroclastic flows . Two Decade Volcanoes that erupted in 1991 provide examples of stratovolcano hazards. On 15 June, Mount Pinatubo erupted and caused an ash cloud to shoot 40 km (25 mi) into
5940-449: The 1920s. Its terminus has retreated about 4 kilometres (2.5 miles), having formerly flowed around both sides of a north–south trending ridge. A small moraine-dammed lake lies along the southwestern margin of Twin Glacier. Hoodoo Glacier and Twin Glacier are separated by a ridgeline extending north of Hoodoo Mountain. They have cut deep valleys into the older regional bedrock and have interacted with Hoodoo Mountain intermittently since
6050-601: The 1940s; the most detailed studies occurred in the 1990s and 2000s. The area has a mostly cool and wet climate with heavy precipitation. As a result, a limited number of mammals live around Hoodoo Mountain. Trees of the pine and willow families form forests in the regional river valleys and on the lower slopes of the volcano. They compose one of many ecoregions that occur throughout British Columbia. Due to its remoteness, Hoodoo Mountain can only be accessed by air, by water or by trekking great distances on foot. The closest communities are more than 30 kilometres (19 miles) away from
6160-481: The 1982 eruption of Galunggung in Java , British Airways Flight 9 flew into the ash cloud, causing it to sustain temporary engine failure and structural damage. Although no crashes have happened due to ash, more than 60, mostly commercial aircraft , have been damaged. Some of these incidents resulted in emergency landings. Ashfalls are a threat to health when inhaled and are also a threat to property. A square yard of
6270-585: The 5,321 m (17,457 ft) high Andean volcano. The ensuing lahar killed 25,000 people and flooded the city of Armero and nearby settlements. As a volcano forms, several different gases mix with magma in the volcanic chamber. During an eruption the gases are then released into the atmosphere which can lead to toxic human exposure. The most abundant of these gases is H 2 O ( water ) followed by CO 2 ( carbon dioxide ), SO 2 ( sulfur dioxide ), H 2 S ( hydrogen sulfide ), and HF ( hydrogen fluoride ). If at concentrations of more than 3% in
6380-647: The Alaskan community of Wrangell by boating up the Stikine and Iskut rivers. Stratovolcano A stratovolcano , also known as a composite volcano , is a conical volcano built up by many alternating layers ( strata ) of hardened lava and tephra . Unlike shield volcanoes , stratovolcanoes are characterized by a steep profile with a summit crater and explosive eruptions. Some have collapsed summit craters called calderas . The lava flowing from stratovolcanoes typically cools and solidifies before spreading far, due to high viscosity . The magma forming this lava
6490-610: The Boundary Ranges Ecoregion; black cottonwood occur on their floodplains. A limited number of mammal species thrive in this ecoregion, such as hoary marmots and mountain goats , which inhabit the alpine tundra zone. The Boundary Ranges Ecoregion is part of the Coast and Mountains Ecoprovince which forms part of the Humid Maritime and Highlands Ecodivision. The Boundary Ranges Ecoregion is subdivided into three ecosections ,
6600-509: The GSC, Jim Nicholls of the University of Calgary , Jeff Schmok and Guy Cross of Golder Associates , Alison Rust, Ben Edwards and Kelly Russell of the University of British Columbia , and Trevor Page of Lancaster University . By 2002, Hoodoo Mountain was no longer the least studied volcano of the Stikine Subprovince. The Hoodoo Mountain area contains several large mining camps within the floodplain of
6710-473: The Iskut River and pose a major hazard to mining operations upstream due to rising waters. A major eruption could also significantly melt the summit ice cap or the adjacent glaciers to produce large-scale flooding of the Iskut River and the lower Stikine River . Such flooding could significantly disrupt the Stikine River salmon fishery, although it would not be as disruptive to mining operations. A jökulhlaup
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#17328525673336820-553: The Iskut River. Prospecting in Bronson Creek commenced as early as 1907, during which time several mining claims had been staked. This was followed by drifting , trenching and stripping of several gold -bearing veins between 1910 and 1920. A drilling program conducted by the Hudson Bay Mining and Smelting Company from 1954 to 1960 identified copper prospects. In 1964, Cominco optioned claims from Jodi Explorations and
6930-906: The Johnny Mountain Mine since its closure in 1993. In 1982, Cominco staked two mining claims over their Red Bluff property and adjacent ground near the junction of the Craig and Iskut rivers. A geochemical survey consisting of 26 rock and 36 soil samples was completed by Cominco in 1985. Exploration work from 1986 to 1987 included geochemical soil surveys , trenching and 15,494 metres (50,833 feet) of diamond drilling in 86 holes. The Snip Mine began as an underground exploration program in March 1988; three levels were established 180 metres (590 feet), 300 metres (980 feet) and 340 metres (1,120 feet) underground. About 41,000 metres (135,000 feet) of underground diamond drilling and 4,200 metres (13,800 feet) of underground work
7040-524: The Mount Edziza volcanic complex. A 12-millimetre-thick (0.47-inch) trachytic tephra layer of unknown origin occurs in sediments at Bob Quinn Lake 60 kilometres (37 miles) northeast of Hoodoo Mountain. The areal distribution of this tephra is poorly constrained but it may extend further to the east. Hoodoo Mountain is a possible source of this tephra due to its location along the trajectory of any ash plume from this volcano. The exact age of this tephra layer
7150-590: The Southern Boundary Ranges Ecosection being the main ecosection at Hoodoo Mountain. This ecosection is cut by several streams, including the Salmon , Bear and Unuk rivers, which drain directly into marine channels or sounds . The only settlements in the Southern Boundary Ranges Ecosection are Kincolith , Stewart and Hyder , the latter two of which are connected by the Stewart Highway . There
7260-652: The Tuksi Mining Company. A drilling program to test copper mineralization on the Red Bluff claim was completed by Cominco in 1965. Texas Gulf Sulphur examined the area for its copper and base metal content from 1973 to 1974. Exploration of the Pickaxe Vein by Skyline Gold began in 1980 to define its gold potential. This was followed by the discovery of the Discovery Vein in 1981, which led to further drilling and
7370-799: The Twin Glacier valley where they spread out into a broad terminal lobe. The Southwest Flow travelled about 3 kilometres (1.9 miles) down slope to near the Hoodoo River. These lava flows are considered by the Smithsonian Institution 's Global Volcanism Program to have been erupted in 7050 BCE. However, the Southwest Flow may be much younger as age estimates of more than 180 years have been obtained from tree-ring dating on living trees. This lava flow has also not undergone erosion and it still attains its original characteristics even though it
7480-816: The air, when breathed in CO 2 can cause dizziness and difficulty breathing. At more than 15% concentration CO 2 causes death. CO 2 can settle into depressions in the land, leading to deadly, odorless pockets of gas. SO 2 classified as a respiratory, skin, and eye irritant if come into contact with. It is known for its pungent egg smell and role in ozone depletion and has the potential to cause acid rain downwind of an eruption. H 2 S has an even stronger odor than SO 2 as well as being even more toxic. Exposure for less than an hour at concentrations of over 500 ppm causes death. HF and similar species can coat ash particles and once deposited can poison soil and water. Gases are also emitted during volcanic degassing, which
7590-741: The air. It produced large pyroclastic surges and lahar floods that caused a lot of damage to the surrounding area. Pinatubo , located in Central Luzon just 90 km (56 mi) west-northwest of Manila , had been dormant for six centuries before the 1991 eruption. This eruption was one of the 2nd largest in the 20th century. It produced a large volcanic ash cloud that affected global temperatures, lowering them in areas as much as .5 °C. The volcanic ash cloud consisted of 22 million tons of SO 2 which combined with water droplets to create sulfuric acid . In 1991 Japan's Unzen Volcano also erupted, after 200 years of inactivity. It's located on
7700-458: The base of Hoodoo Mountain, both of which are actively retreating. Hoodoo Glacier surrounding its northwestern base is the source of the Hoodoo River which flows south into the Iskut River . It has lost about 100 metres (330 feet) of its total thickness over the last 700 years and its terminus has retreated at least 2 kilometres (1.2 miles) since the 1920s. At the terminus of Hoodoo Glacier
7810-425: The base of the volcano except for its southeastern margin where they have been partially overrun by younger lava flows. These cliffs form a broad bench at an elevation of approximately 1,300 metres (4,300 feet) and are 100 to 200 metres (330 to 660 feet) high. The upper set of cliffs surround the summit and are between 50 and 100 metres (160 and 330 feet) high. Both sets of cliffs formed as a result of lava erupting in
7920-585: The discovery of a high-grade gold vein in 1982 that became known as the 16 Vein. Surveying, drilling and trenching was carried out by Skyline Gold, Placer Development and Anaconda Canada Exploration between 1982 and 1988. The Johnny Mountain Mine commenced production in November 1988 after having been engaged in pre-production since January of that year. This small underground mine operated until August 1990 when high operating costs and low gold prices forced it to shut down. This
8030-540: The flank of a volcano collapses in a massive landslide) can only trigger the eruption of a very shallow magma chamber . Magma differentiation and thermal expansion also are ineffective as triggers for eruptions from deep magma chambers . In recorded history , explosive eruptions at subduction zone ( convergent-boundary ) volcanoes have posed the greatest hazard to civilizations. Subduction-zone stratovolcanoes, such as Mount St. Helens , Mount Etna and Mount Pinatubo , typically erupt with explosive force because
8140-403: The flows were erupted subaerially after the regional ice had disappeared from lower elevations. Lava flows on the north–central flank display radially-oriented cooling joints. The Northwest Flow travelled about 3 kilometres (1.9 miles) down slope and partially covers cliffs at the base of Hoodoo Mountain. Lava flows on the southeastern flank drape down 50-metre-high (160-foot) cliffs and extend into
8250-478: The ground. Volcanic Bombs are associated with Strombolian and Vulcanian eruptions and basaltic lava . Ejection velocities ranging from 200 to 400 m/s have been recorded causing volcanic bombs to be destructive. Lahars (from a Javanese term for volcanic mudflows) are a mixture of volcanic debris and water. Lahars can result from heavy rainfall during or before the eruption or interaction with ice and snow. Meltwater mixes with volcanic debris causing
8360-458: The high population density of the surrounding Metropolitan Naples area (totaling about 3.6 million inhabitants). In addition to potentially affecting the climate, volcanic ash clouds from explosive eruptions pose a serious hazard to aviation . Volcanic ash clouds consist of ash which is made of silt or sand sized pieces of rock, mineral, volcanic glass . Ash grains are jagged, abrasive, and don't dissolve in water. For example, during
8470-522: The hoary marmot. Hoary marmots also occur on several islands in Alaska and fossils dating back to the Pleistocene , including some from islands no longer inhabited by the species. The three currently recognized subspecies are: Hoary marmots are diurnal and herbivorous , subsisting on leaves, flowers, grasses, and sedges. Predators include golden eagles , grizzly and black bears , wolverines , coyotes , red foxes , lynxes , wolves , and cougars . They live in colonies of up to 36 individuals, with
8580-500: The island of Kyushu about 40 km (25 mi) east of Nagasaki . Beginning in June, a newly formed lava dome repeatedly collapsed. This generated a pyroclastic flow that flowed down the mountain's slopes at speeds as high as 200 km/h (120 mph). The 1991 eruption of Mount Unzen was one of the worst volcanic disasters in Japan's history, once killing more than 15,000 people in 1792. The eruption of Mount Vesuvius in 79 AD
8690-501: The latter of which are in the form of pillow lavas , tuff breccias and hyaloclastite . All of these volcanoes were active in the last 150,000 years; the latest eruption occurred from The Volcano about 150 years ago. The remaining Iskut volcanoes are Cinder Mountain , Little Bear Mountain and the Cone Glacier , Iskut Canyon , Second Canyon , Snippaker Creek , King Creek and Tom MacKay Creek cones. Hoodoo Mountain
8800-507: The litter of two to five young is born between late May and mid-June. The young emerge from their birth den at three to four weeks of age, by which time they have a full coat of fur and are already beginning to be weaned . The young are initially cautious, but begin to exhibit the full range of nonreproductive adult behavior within about four weeks of emerging from the burrow. Subadults initially remain with their birth colony, but typically leave at two years of age, becoming fully sexually mature
8910-655: The mid- crust . Several tephra layers in the Bob Quinn Lake , Dease Lake and Finlay River areas of northern British Columbia may have originated from Hoodoo Mountain. The first eruptive period 85,000 years ago produced massive subglacial lava flows and associated hyaloclastite breccia. These volcanic deposits are mainly exposed on the southwestern and northwestern flanks where they are about 500 to 1,000 metres (1,600 to 3,300 feet) thick. The lava flows display small diameter columnar joints and are aphanitic in nature with low vesicularity. It remains unclear whether or not
9020-457: The mid-1980s, indicating possible future eruptions and volcanic hazards . Hoodoo Mountain lies in a remote area of Cassiar Land District that has undergone mineral exploration since at least the early 1900s. This exploration led to the discovery of copper , silver and gold within the Iskut River floodplain where two underground mines operated between 1988 and 1999. Geological studies have been conducted at Hoodoo Mountain since at least
9130-464: The mine's lifespan amounted to 249,276 kilograms (549,560 pounds) of copper, 32,093,000 grams (1,132,000 ounces) of gold, and 12,183,000 grams (429,700 ounces) of silver from 1.2 million tonnes of ore mined. Mineral exploration has occurred at the Snip Mine intermittently since its closure in 1999. Hoodoo Mountain is in a remote location with no established road access. The closest point accessible by road
9240-443: The morning doing so, although they will shelter in their burrows or otherwise seek shade in especially warm weather. They forage for the rest of the day, returning to their burrows to sleep during the night. In areas frequented by people, hoary marmots are not shy. Rather than running away at first sight, they will often go about their business while being watched. Mating occurs after hibernation, and two to four young are born in
9350-576: The mountain. Hoodoo Mountain lies within the Boundary Ranges Ecoregion, a mountainous region of the Coast Mountains in southeastern Alaska and northwestern British Columbia characterized by rugged, largely ice-capped mountains of granitic and metamorphic rocks . Mountain hemlock , western hemlock and Sitka spruce form forests on valley bottoms and lower valley slopes. They are overlooked by an extensive alpine tundra zone consisting primarily of large icefields , glaciers and barren rock. Several large river valleys with wide braided channels penetrate
9460-630: The north and are the sources of two meltwater streams. These streams flow along the western and eastern sides of the volcano before draining into the Iskut River. Much of Hoodoo Mountain was formed beneath glacial ice and it has been overlain by glaciers or an ice cap throughout much of its history. The main rock types composing the volcano are phonolite and trachyte , which were deposited during six periods of eruptive activity beginning about 85,000 years ago. Most of these eruptive periods were characterized by steady flows of lava but at least one period of explosive activity occurred as indicated by
9570-829: The northwestern side of Hoodoo Mountain is the Northwest Flow, a lava flow with well-preserved levees. Lava channels up to 20 metres (66 feet) wide occur throughout the flow. The Southwest Flow is a large lava flow on the southwestern side of Hoodoo Mountain that appears to have issued from a poorly formed cinder cone. Hoodoo Mountain has experienced at least six eruptive periods over the last 85,000 years. This includes three periods involving volcano-ice interaction and three periods with no apparent ice involvement. They were marked by pyroclastic eruptions, lava flows and subglacial eruptions of peralkaline magmas. These magmas were phonolitic and trachytic in composition, having possibly evolved from differentiation of alkali basaltic melts in
9680-502: The north–central and southwestern flanks. Individual flows vary from 10 to 30 metres (33 to 98 feet) thick and are separated by 1 to 10 metres (3.3 to 32.8 feet) of lava breccia, giving the sequence a total thickness of around 200 metres (660 feet). The lava flows do not appear to have interacted with glacial ice, suggesting at least the upper flanks of Hoodoo Mountain were ice-free at the time of their eruption. Columnar joints more than 1 metre (3.3 feet) thick characterize these flows. After
9790-474: The presence of pyroclastic rocks . The latest eruptive period began about 10,000 years ago with the eruption of extensive lava flows that cover the north–central, northwestern and southeastern mountain slopes. A lava flow covering the southwestern slope may have been produced by a more recent eruption within the last couple of hundred years. Although no historical eruptions are known at Hoodoo Mountain, there have been periods of seismic activity since at least
9900-411: The rest of the NCVP. Heart Peaks, Level Mountain and Mount Edziza are the largest NCVP centres by volume, the latter two of which have experienced volcanism for a much longer timespan than any other NCVP centre. Hoodoo Mountain, Level Mountain and Mount Edziza are the only NCVP centres that contain volcanic rocks of both mafic and intermediate to felsic composition. The highest of the four complexes
10010-407: The sequence. A 10-metre-thick (33-foot) subaerial lava flow travelled down the north–central and northeast flanks of Hoodoo Mountain during the latter stages of this eruptive period. It directly overlies the pyroclastic sequence and contains abundant fresh and devitrified glass. The fourth eruptive period 54,000 years ago produced a subaerially erupted sequence of up to five stacked lava flows on
10120-415: The silver-gray fur on their shoulders and upper back; the remainder of the upper parts have drab- or reddish-brown fur. The head is black on the upper surface, with a white patch on the muzzle, white fur on the chin and around the lips, and grizzled black or brown fur elsewhere. The feet and lower legs are black, sometimes with white patches on the fore feet. Marmots have long guard hairs that provide most of
10230-460: The size of Mount Pinatubo affected the weather for a few years; with warmer winters and cooler summers observed. A similar phenomenon occurred in the April 1815, the eruption of Mount Tambora on Sumbawa island in Indonesia . The Mount Tambora eruption is recognized as the most powerful eruption in recorded history. Its eruption cloud lowered global temperatures as much as 0.4 to 0.7 °C. In
10340-414: The southwestern side of Hoodoo Mountain is a vertical rock column that reaches more than 100 metres (330 feet) in height. It is the eroded remains of a volcanic vent that was fed by a west-trending dike. Horn Ridge, a 20-metre-high (66-foot) ridge on the north side of Hoodoo Mountain, consists of highly vesicular lava flows that are locally heavily jointed. The northeastern side of Hoodoo Mountain contains
10450-594: The spring. Males establish "harems", but may also visit females in other territories. Hoary marmots breed shortly after, or even before, their emergence from hibernation burrows in May and in some areas (such as the eastern Cascade foothills of Washington State) as early as February. Courtship consists of sniffing the genital region, followed by mounting, although mounting has also been observed between females. Females typically raise litters only in alternate years, although both greater and lesser frequencies have been reported on occasion. Gestation lasts 25 to 30 days, so
10560-422: The subglacial eruptions during this period completely melted the overlying ice. Glacial till underlying the southwestern flank indicates the area had already experienced past glaciations before the onset of volcanic activity. Subaerial eruptions from near the summit took place during the second eruptive period 80,000 years ago. Lava travelled down slope from an elevation of roughly 1,350 metres (4,430 feet) but
10670-483: The summer months of June, July and August while up to 1,300 millimetres (51 inches) of precipitation can be expected during the winter months of December, January and February. In summer the average temperature is 6.9 degrees Celsius (44.4 degrees Fahrenheit) whereas the average winter temperature sits at −6.4 degrees Celsius (20.5 degrees Fahrenheit). The annual average temperature is −0.8 degrees Celsius (30.6 degrees Fahrenheit). Two valley glaciers wrap partially around
10780-480: The third eruptive period took place between 80,000–54,000 years ago. This explosivity generated pyroclastic flows on the northern flank where they deposited a roughly 100-metre-thick (330-foot) sequence of pyroclastic material. The sequence comprises non- welded lapilli tuff within a matrix of yellow to light green ash , as well as three highly welded lenses up to about 5 metres (16 feet) thick. Volcanic glass of phonolitic or trachytic composition occurs within
10890-418: The visible colour of their pelage , and a dense, soft underfur that provides insulation. The greyish underparts of the body lack this underfur, and are more sparsely haired than the rest of the body. Hoary marmots moult in the early to mid summer. The feet have slightly curved claws, which are somewhat larger on the fore feet than on the hind feet. The feet have hairless pads, enhancing their grip. The tail
11000-409: The volcano is named, are as much as 150 metres (490 feet) in height and give the mountain a unique appearance. In 1919, a landslide removed lava rock from a 580-metre-wide (1,900-foot) section on the western side of Hoodoo Mountain. Two sets of prominent cliffs partially circumscribe Hoodoo Mountain, which give the volcano a discontinuous, step-like topographic profile. The lower set of cliffs delimit
11110-404: The volcano. An expedition consisting of university, GSC and industry scientists was organized in 1997 to assess the nature and magnitude of hazards posed by Hoodoo Mountain. This included mapping of the shape of the summit ice cap using ground-penetrating radar and ice radar, as well as the production of a preliminary hazard assessment for the Iskut area. Analysis of data indicated the absence of
11220-453: The volcano. Like other volcanoes in the NCVP, Hoodoo Mountain is not monitored closely enough by the GSC to ascertain its activity level. The Canadian National Seismograph Network has been established to monitor earthquakes throughout Canada, but it is too far away to provide an accurate indication of activity under the mountain. It may sense an increase in seismic activity if Hoodoo Mountain becomes highly restless, but this may only provide
11330-512: The western base of Hoodoo Mountain formed during this eruptive period. Subsequent glacial movements over these flows created north–south trending striations that are consistent with current movements of the Hoodoo and Twin glaciers. Both of these valley glaciers are now roughly 500 metres (1,600 feet) below the striations due to their ongoing glacial retreat. After the regional ice had disappeared from lower elevations, subaerial explosive eruptions of
11440-412: The world. The SO 2 in this cloud combined with water (both of volcanic and atmospheric origin) and formed sulfuric acid , blocking a portion of the sunlight from reaching the troposphere . This caused the global temperature to decrease by about 0.4 °C (0.72 °F) from 1992 to 1993. These aerosols caused the ozone layer to reach the lowest concentrations recorded at that time. An eruption
11550-463: The year following the eruption, most of the Northern Hemisphere experienced cooler temperatures during the summer. In the northern hemisphere , 1816 was known as the " Year Without a Summer ". The eruption caused crop failures, food shortages, and floods that killed over 100,000 people across Europe , Asia , and North America . Hoary marmot The hoary marmot ( Marmota caligata )
11660-454: The youngest tephra layer suggest an early Holocene age for this volcanic material. The glass composition of the tephras is similar to the average whole-rock chemistry of the phonolitic lava flows produced during the final eruptive period at Hoodoo Mountain. However, this eruptive period is not known to have produced any pyroclastic deposits or tephras. Therefore other possible sources have been considered, including Level Mountain, Heart Peaks and
11770-452: Was completed between August 1988 and October 1989. By mid-1990, 63,700 metres (209,000 feet) of surface and underground diamond drilling had been completed. The Snip Mine, owned jointly by Cominco and Prime Resources, began production in January 1991. An airstrip was used continuously to ship ore concentrate from the mine until May 1999 when all mining operations ceased. Production throughout
11880-435: Was followed by closure of the ore mill in September of that year. The mine remained closed until 1993 when further mining and milling took place. A total of 196,358 tonnes of ore was mined from 1988 to 1993, from which 1,008,109 kilograms (2,222,500 pounds) of copper, 4,348,814 grams (153,399.9 ounces) of silver and 2,815,393 grams (99,310.1 ounces) of gold was recovered. Intermittent mineral exploration has taken place at
11990-410: Was renamed after these animals to help make it more marketable as a resort. The closest relatives of the species are the yellow-bellied , Olympic , and Vancouver Island marmots, although the exact relationships are unclear. The hoary marmot is a large, bulky, ground squirrel, with short, heavy limbs, and a broad head. Adults range from 62 to 82 cm (24 to 32 in) in total length, including
12100-430: Was then confined by thick glacial ice at an elevation of about 700 metres (2,300 feet). Here, the lava cooled and pooled to create the lower discontinuous set of cliffs around the entire base of Hoodoo Mountain. These ice-marginal lava flows vary from about 30 metres (98 feet) to more than 200 metres (660 feet) thick and often contain horizontally oriented columnar joints, indicative of a vertical cooling surface. The Wall at
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