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120-804: At least four large volcanoes are grouped with the Northern Cordilleran Volcanic Province, including Hoodoo Mountain in the Boundary Ranges , the Mount Edziza volcanic complex on the Tahltan Highland , and Level Mountain and Heart Peaks on the Nahlin Plateau . These four volcanoes have volumes of more than 15 km (3.6 cu mi), the largest and oldest which is Level Mountain with an area of 1,800 km (690 sq mi) and

240-708: A maritime glacial climate that 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

360-491: 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

480-503: 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

600-480: 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

720-406: 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

840-432: 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

960-922: 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

1080-498: 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

1200-483: 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

1320-412: 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

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1440-778: 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

1560-531: A result, volcanism in the Northern Cordilleran Volcanic Province is also not related to back-arc basin volcanism. When the stored energy is suddenly released by slippage across the fault at irregular intervals, it can create very large earthquakes , such as the magnitude  8.1 Queen Charlotte Islands earthquake of 1949 . As these far-field forces stretch the North American crust, the near surface rocks fracture along steeply dipping faults parallel to

1680-502: 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

1800-514: A sequence of north-trending faults were mapped that seem to represent young rifting events parallel with the southwestern boundary of the Northern Cordilleran Volcanic Province. These rift-related faults might have been active as recently as five million years ago and they might have connections with adjacent Miocene and younger volcanic activity in the southern part of the Northern Cordilleran Volcanic Province. In addition, brittle faults with similar north-trending directions might enlarge as far north as

1920-453: A shallower depth than one from a zone with a reduced geothermal gradient that also records a temperature of 900 °C (1,650 °F). Further evidence that indicate lithospheric thickening beneath the middle portion of Stikinia include the increased profusion of cognate inclusion and plagioclase megacrysts in volcanic rocks from the southern portion of the volcanic province, which might be evidence of magma ponding and magma crystallization in

2040-574: 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

2160-493: 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

2280-516: A volume of more than 860 km (210 cu mi). Apart from the large volcanoes, several smaller volcanoes exist throughout the Northern Cordilleran Volcanic Province, including cinder cones which are widespread throughout the volcanic zone. Most of these small cones have been sites of only one volcanic eruption; this is in contrast to the larger volcanoes throughout the volcanic zone, which have had more than one volcanic eruption throughout their history. The Northern Cordilleran Volcanic Province

2400-677: 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

2520-415: 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

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2640-538: 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

2760-547: 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,

2880-572: Is a broader name, to encompass a broader geographic area, in which the most recent volcanism has a similar character (mainly alkaline, mafic volcanic rocks), a similar age range ( Miocene to Holocene ), and a similar tectonic setting (transtension). Hoodoo Mountain Hoodoo Mountain , sometimes referred to as Hoodoo Volcano , is a potentially active stratovolcano in the Northern Interior of British Columbia , Canada. It

3000-592: 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

3120-551: Is a sequence of late Paleozoic and Mesozoic aged volcanic, plutonic and sedimentary rocks interpreted to have been created in an island arc environment that were later placed along a pre-existing continental margin . The Cache Creek Terrane is believed to have formed widely in a pre-existing oceanic basin . It comprises late Paleozoic to Mesozoic aged oceanic melange and abyssal peridotites intruded by younger granitic intrusions. The Yukon–Tanana and Cassiar terranes consist of shifted sedimentary and metamorphic rocks that were derived from

3240-440: 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

3360-426: 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 the north and are the sources of two meltwater streams. These streams flow along the western and eastern sides of

3480-586: Is independent of lithosphere structure. In contrast, clear glassy plagioclase megacrysts are found largely at the southern end of the Northern Cordilleran Volcanic Province and largely within the boundaries of the Stikinia terrane. This suggests the plagioclase megacrysts have a source that is sensitive to the Earth's lithosphere, including contamination or magma ponding. Megacrysts made of plagioclase and clinopyroxene regionally show significant evidence of reaction with

3600-639: 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 is one of many prominent peaks within the Boundary Ranges of the Coast Mountains . Its flat-topped summit

3720-404: 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

Northern Cordilleran Volcanic Province - Misplaced Pages Continue

3840-786: Is part of an area of intensive earthquake and volcanic activity around the Pacific Ocean called the Pacific Ring of Fire . However, the Northern Cordilleran Volcanic Province is commonly interpreted to be part of a gap in the Pacific Ring of Fire between the Cascade Volcanic Arc further south and the Aleutian Arc further north. But the Northern Cordilleran Volcanic Province is recognized to include over 100 independent volcanoes that have been active in

3960-562: Is subdivided into three ecosections , 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

4080-539: 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

4200-412: 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

4320-534: 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

4440-496: 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

4560-628: The Cascadia subduction zone , defined by the eastward extension of the northern edge of the subducting Juan de Fuca Plate . These two zones divide the Northern Cordilleran Volcanic Province from modern volcanic zones further south, including the broad Chilcotin Plateau , the east–west trending Anahim Volcanic Belt and the monogenetic Wells Gray-Clearwater volcanic field in the British Columbia Interior . The eastern boundary of

4680-565: The Denali Fault , which ruptured a 200 km (120 mi) portion of its central segment during the 2002 Denali earthquake , the Tintina Fault is considered inactive. Despite this classification, researchers noted a magnitude 5.3 right-lateral event in 1972 and a relatively young ( Holocene ) 14 km (8.7 mi) scarp with a maximum offset of 2.5 m (8 ft 2 in). This British Columbia -related article

4800-589: The Fort Selkirk Volcanic Field in central Yukon, Prindle Volcano in easternmost Alaska and at Castle Rock and the Iskut River in northern British Columbia. Felsic intrusive xenoliths are a lot more common and usually originate from adjacent granitic intrusions, including those that form the Coast Mountains. More than 14 volcanic zones throughout the Northern Cordilleran Volcanic Province comprise xenoliths that originated from

4920-470: 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

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5040-647: 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

5160-466: The Stewart Highway . There 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

5280-459: The boundary between the Earth's crust and mantle is shallowest beneath the northern portion of the Northern Cordilleran Volcanic Province. Therefore, the temperature ranges for the northernmost xenolith series is about one-half the temperature range found in xenoliths at the southern portion of the volcanic province. Megacrysts , crystals or grains that are considerably larger than the encircling matrix , are commonly found in lava flows throughout

5400-487: The last glacial period have been eroded and overridden by glacial ice, affording a less distinctive form to these older landforms. For example, lava beds at least a million years old in central Yukon contain unconsolidated glacial deposits that were deposited when glacial ice rode on top of the lava flows comprising the lava beds. Subvolcanic intrusions in the Northern Cordilleran Volcanic Province are exposed in areas of high relief. This includes volcanic plugs found at

5520-514: 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

5640-599: The 18th century. Lava Fork at the British Columbia-Alaska border is influenced by lava flows from a recent volcanic eruption that later collapsed into underlying lava tubes after the lava solidified. Sections of these collapsed lava tubes now form volcanic pits. Extensive areas of nearly flat-lying lava flows throughout the Northern Cordilleran Volcanic Province can cover areas of at least 100 km (39 sq mi) and are generally composed of highly-fluid basaltic lava. However, lava plains that pre-date

5760-454: 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

5880-601: 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

6000-724: The Alaskan community of Wrangell by boating up the Stikine and Iskut rivers. Tintina Fault The Tintina Fault is a large right-lateral strike-slip fault in western North America , extending from Flathead Lake, Montana to the centre of the U.S. state of Alaska . It represents the Yukon continuum between the Rocky Mountain Trench in the northern United States and the Kaltag Fault in Alaska. Unlike

6120-595: 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

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6240-489: The Earth's upper mantle under the Northern Cordilleran Volcanic Province is the existence of a slab window. However, not much of a noticeable evidence linking the production of magma in the upper mantle to a possible tectonic system has been stated. The existence of a fault next to the western flank of the Mount Edziza volcanic complex is normally considered to be the prime structural evidence for continental rifting in

6360-657: The Earth's mantle and are located mainly at the Yukon–Tanana Terrane, the Cache Creek Terrane and at volcanoes occupying the Paleozoic and Mesozoic Stikinia terrane. They consist of lherzolite, harzburgite , wehrlite , dunite , websterite and garnet composed pyroxenite . The highest and lowest temperatures recorded by mantle xenoliths increase to the south and decrease to the north. Mantle xenoliths at Prindle Volcano in easternmost Alaska record

6480-520: 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

6600-751: The Geological Survey of Canada in 1991 as a group of volcanic deposits centered around the Stikine River in northwestern British Columbia. As more mapping and dating of volcanic deposits was completed in the Western Cordillera, the Stikine Volcanic Belt was expanded to include volcanic deposits further and further from the geographic area associated with the name Stikine. In part for this reason, scientists Ben Edwards and James Russell redefined this area of volcanism as

6720-484: 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

6840-569: 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

6960-924: 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

7080-631: The Lakelse Hot Springs. Hot springs are also present in Iskut River Hot Springs Provincial Park and Choquette Hot Springs Provincial Park in northwestern British Columbia. Xenoliths , rock fragments that become enveloped in a larger igneous rock , are widespread in the Northern Cordilleran Volcanic Province. Xenoliths that originated in the Earth's crust include rich metamorphic rocks and felsic intrusive rocks. Granulite xenoliths exist mainly at

7200-575: The Mount Edziza volcanic complex, Level Mountain, Hoodoo Mountain and in the Atlin and Maitland areas. Volcanic plugs in the Atlin and Maitland areas consist of olivine nephelinite and basanite magmas. Minor plugs made of gabbroic and granitic magma are associated with volcanic stratigraphy at the Mount Edziza volcanic complex and Level Mountain. The bedrock of the Northern Cordilleran Volcanic Province consists of four large terranes , known as Stikinia, Cache Creek , Yukon–Tanana and Cassiar . Stikinia

7320-474: 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

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7440-412: The North American continent. The southern boundary of the Northern Cordilleran Volcanic Province is parallel with southwestern Stikinia and is characterized by separate volcanic vents and erosional remains of lavas south of the small community of Stewart . The southern boundary of the Northern Cordilleran Volcanic Province also parallels with a gap in modern volcanism and the supposed northern boundary of

7560-414: The Northern Cordilleran Volcanic Province display trace element abundances and isotopic compositions that are logical with an asthenospheric source like those for average oceanic island basalt and for alkaline basalts younger than five million years in the rift-related Basin and Range Province of southwestern United States and northwestern Mexico . One hypothesized explanation for oceanic island basalt in

7680-668: The Northern Cordilleran Volcanic Province is being stretched at a rate of about 2 cm (1 in) per year. This incipient rifting formed as a result of the Pacific Plate sliding northward along the Queen Charlotte Fault , on its way to the Aleutian Trench , which extends along the southern coastline of Alaska and the adjacent waters off the southern coast of the Kamchatka Peninsula . As

7800-545: The Northern Cordilleran Volcanic Province is bounded by the Cassiar Terrane and is adjoined by a cluster of volcanic plugs in central British Columbia. The northern and western boundaries are adjoined by the Yukon–Tanana and Cache Creek terranes where there lies volcanics in eastern Alaska and weathered remains of lava flows just north and west of Dawson City in west-central Yukon. The Tintina and Denali faults are

7920-416: The Northern Cordilleran Volcanic Province is magmas are mainly alkaline , it includes highly alkaline and peralkaline rock types, the main spatial-temporal pattern of volcanism is in the middle of the volcanic province followed by movement to the south, north and possibly northeast, heat flow in the Northern Cordilleran Volcanic Province is high, seismic activity is largely absent in the volcanic province and

8040-440: The Northern Cordilleran Volcanic Province, indicating magmatic heat is present under the Northern Cordilleran Volcanic Province. They are formed if water percolates deeply through the crust and heats up from the primal magmatic heat under the surface. After the groundwater is heated, the heated groundwater rises to the surface as a hot spring. In some cases, the heated groundwater may rise along extensional faults related to rifting in

8160-509: The Northern Cordilleran Volcanic Province, volcanism throughout the past 1.6 million years is possibly due to repetitive upper mantle upwelling and adjacent transtension throughout the Queen Charlotte Fault, accommodated partly by numerous east–west trending fault zones that extend all through the Northern Cordilleran Volcanic Province. The volcanics comprising the Northern Cordilleran Volcanic Province are consistent with

8280-418: The Northern Cordilleran Volcanic Province, would aid the formation of high-level reservoirs of capable size and thermal activity to maintain long-lived fractionation. The variety of different temperature ranges from xenoliths throughout the Northern Cordilleran Volcanic Province indicate that a narrow lithosphere lies under the northern portion of the volcanic province and a more dense lithosphere lies under

8400-551: The Northern Cordilleran Volcanic Province. As a geographic descriptor, application of the name Stikine to volcanic rocks exposed along the Yukon River seems a bit odd and confusing. As well, a much older group of totally unrelated volcanic rocks comprise the Stikine Assemblage, which also mainly occurs within the geographic area informally referred to as Stikine Country . The Northern Cordilleran Volcanic Province

8520-414: The Northern Cordilleran Volcanic Province. However, more recent mapping and seismic studies in the Coast Mountains have documented the presence of brittle rift-related faults southwest of the small community of Stewart in northwestern British Columbia. But these faults were in a matter of dispute in 1997 by geologists, stating these faults were last active between 20 and five million years ago. In 1999,

8640-473: The Northern Cordilleran Volcanic Province. The Lakelse Hot Springs near Lakelse Lake Provincial Park in northern British Columbia is interpreted to be one such example. With a temperature of 89 °C (192 °F), the springs are the hottest in Canada. It is also possible the magma associated with the Nass Valley eruption 250 years ago to the north rose along the same north trending fault lines fueling

8760-435: The Northern Cordilleran Volcanic Province. They consist of three different groups, including kaersutitic amphibole megacrysts, clinopyroxene megacrysts and plagioclase megacrysts. Megacrysts made of kaersutite are known to be found mainly at Llangorse Mountain in northern British Columbia. Black glassy clinopyroxene megacrysts are widespread throughout the Northern Cordilleran Volcanic Province, suggesting their creation

8880-433: The Pacific Ring of Fire, the Northern Cordilleran Volcanic Province has its origins in continental rifting —an area where the Earth's crust and lithosphere is being pulled apart. This differs from other portions of the Pacific Ring of Fire as it consists largely of volcanic arcs formed by subducting oceanic crust at oceanic trenches along continental margins circling the Pacific Ocean . The continental crust at

9000-460: The Queen Charlotte Fault 10 million years ago produced consequent strain throughout the northern portion of the Western Cordillera, resulting in crustal thinning and decompression melting of oceanic island basalt-like mantle to create alkaline volcanism. Several plate motion models indicate a rebound to net compression throughout the Queen Charlotte Fault sometime after four million years ago. Although extensive rifting has not yet been recognized in

9120-591: The Tintina Fault likely occurred during two pulses in the Mid-Cretaceous and early Cenozoic periods, respectively, with the latter probably occurring during the Eocene epoch. Since the Cretaceous, the Tintina Fault has offset 450 km (280 mi) of the surface, although some evidence suggest as much as 1,200 km (750 mi) of offset. The offset caused the Northern Cordilleran Volcanic Province and

9240-581: The Tintina Fault, strike-slip movement along the Denali Fault has offset at least 370 km (230 mi) of the surface. The fault separates mountains of the Insular Belt from mountains east of the fault. Tectonic events in the Insular Belt are also related to movement along the Denali Fault. The term Stikine Volcanic Belt was originally defined by Jack Souther and Christopher Yorath of

9360-680: 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

9480-832: 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

9600-629: The associated magma, including sieve-textured cores and random, resorbed and embayed outer margins wherever they are located. Lava tubes are widespread in the Northern Cordilleran Volcanic Province, and are typically basaltic in composition. At Level Mountain, lava tubes reach diameters of 1 m (3.3 ft) to 2 m (6.6 ft). These owed their origin to highly fluid lavas with temperatures of at least 1,200 °C (2,190 °F). In Nisga'a Memorial Lava Beds Provincial Park of northwestern British Columbia, lava tubes are present that were formed during one of Canada's most recent volcanic eruptions in

9720-469: 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

9840-425: 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

9960-514: The boundaries ( half-grabens ). Grabens are indicative of tensional forces and crustal stretching. Two major north-trending faults hundreds of kilometres long extend along the Northern Cordilleran Volcanic Province. These two rock fractures, known as the Tintina and Denali fault systems, have been tectonically active since the Cretaceous period as strike-slip faults . The Denali fault to

10080-594: 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

10200-532: The fault next to the western flank of the Mount Edziza volcanic complex. These tectonic events might have helped form the structure the Northern Cordilleran Volcanic Province. Subduction beside the northern portion of the Western Cordillera deceased between 43 and 40 million years ago. This finally caused the formation of a slab window under the northern portion of the Western Cordillera 10 million years ago, supporting an entrance to relatively undepleted upper mantle. A switch in relative plate motions at

10320-403: 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

10440-635: The largest fault zones associated with the Northern Cordilleran Volcanic Province rift zone, with all volcanism occurring west of the Tintina Fault and east of the Denali Fault. Physiographically, the Tintina Fault forms the Northern Rocky Mountain Trench and the Tintina Trench , which is the northern extension of the Northern Rocky Mountain Trench. The fastest rates of strike-slip movement along

10560-535: The largest period of volcanism correlates with an interval of net extension between the Pacific and North American plates. A range of more heavily alkaline rock types not commonly found in the Western Cordillera are regionally widespread in the Northern Cordilleran Volcanic Province. These include nephelinite , basanite and peralkaline phonolite , trachyte , and comendite lavas. The most magnesium oxide -rich nephelinites, basanites and alkaline basalts all through

10680-509: 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

10800-423: The lithosphere before a volcanic eruption, and the restricted existence of petrologically evolved rock types in the southern half of the Northern Cordilleran Volcanic Province. If the developed magmas originated from fractionation of mafic magmas, fractionation associated with lithospheric contamination, or entirely from melting of the associated lithosphere, their existence suggests more dense lithosphere lies under

10920-665: 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

11040-457: 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

11160-470: 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

11280-569: The minimum temperature of 860 °C (1,580 °F) and mantle xenoliths from the Fort Selkirk Volcanic Field in central Yukon record the minimum temperature range from 960 to 1,050 °C (1,760 to 1,920 °F). At Castle Rock in northern British Columbia, mantle xenoliths record the maximum temperature of 1,260 °C (2,300 °F), as well as the maximum temperature range from 1,000 to 1,260 °C (1,830 to 2,300 °F). The minimum xenolith temperatures indicate that

11400-580: 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

11520-837: 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

11640-503: 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

11760-445: The past 1.8 million years. At least three of them have erupted in the past 360 years, making it the most active volcanic area in Canada. Nevertheless, the dispersed population within the volcanic zone has witnessed few eruptions due to remoteness and the infrequent volcanic activity. The Northern Cordilleran Volcanic Province has been a zone of active volcanism since it began to form 20 million years ago. Unlike other parts of

11880-474: 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

12000-414: 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

12120-414: The rift zone. Hot magma rises between these fractures to create passive or effusive eruptions . Volcanoes within the Northern Cordilleran Volcanic Province are located along short northerly trending segments which in the northern part of the volcanic province are unmistakenably involved with north-trending rift structures, including synvolcanic grabens and grabens with one major fault line along only one of

12240-559: The rifting environment. Alkaline basalt, lesser hawaiite and basanite magmas from effusive eruptions create the massive shield volcanoes and small cinder cones throughout the volcanic province, several of which comprise lherzolite magma. Felsic magmas from more viscous eruptions create the massive central volcanoes and largely consist of trachyte, pantellerite and comendite lavas. These felsic volcanics are understood to have been created by fractionation of mainly alkali basalt magma in crustal reservoirs. An area of continental rifting, such as

12360-408: 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

12480-538: The southern portion of the Northern Cordilleran Volcanic Province. In the Llangorse section of the Atlin Volcanic Field in northwestern British Columbia, a suite of xenoliths confines the thickness of the Northern Cordilleran Volcanic Province mantle lithosphere to as thin as 18 km (11 mi) and a thickness no more than 39 km (24 mi). Analysis of recent data related to earthquakes in

12600-402: The southern portion of the volcanic province. This indication is further provided if the geothermal gradient inside the lithosphere under the northern portion of the Northern Cordilleran Volcanic Province is greater than that in the southern portion of the province. A greater geothermal gradient would indicate that a xenolith recording a temperature of 900 °C (1,650 °F) was collected from

12720-532: The southwestern portion of the volcanic province indicates that the crust under Stikinia, which comprises the bedrock underlying a large number of volcanoes in the southern portion of the Northern Cordilleran Volcanic Province, is also more dense than the crust under the nearby Coast Plutonic Complex, which consists of a broad belt of granitic and dioritic intrusive rocks that collectively represent more than 140 million years of nearly continuous subduction-related magmatism. Hot springs are present throughout

12840-417: 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

12960-423: 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

13080-484: 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

13200-487: The terrains of which the volcanic province occupies to move northwards. In the context of plate tectonics, strip-slip movement of the Tintina Fault is also related to strike-slip movement along the San Andreas Fault and other extensional or strike-slip fault systems of western North America. To the west, the Denali Fault is the source of minor earthquakes that extend along the length of the fault. In contrast to

13320-480: 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

13440-410: 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

13560-455: 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

13680-408: 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

13800-513: The west and the Tintina fault to the east are nearly 2,000 km (1,200 mi) long, extending from northern British Columbia to central Alaska. Other mechanisms suggested for triggering volcanism in the Northern Cordilleran Volcanic Province include mantle plumes , deglaciation and slab windows , although continental rifting is the most accurate mechanism for activating volcanism in the volcanic zone. Further evidence for continental rifting in

13920-519: 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

14040-456: 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

14160-462: 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

14280-492: 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

14400-431: 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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