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139-690: Stikinia forms the bedrock of numerous volcanoes in the southern portion of the Northern Cordilleran Volcanic Province (NCVP), a Miocene to Holocene geologic province that has its origins in continental rifting . Until recently the Paleozoic rocks that form a non-continuous belt along the western margin of the NCVP (the Stikine assemblage) were only recognized in a restricted area in northern British Columbia, between

278-904: 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. The MEVC 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 complexes: Heart Peaks , Hoodoo Mountain and Level Mountain . The four complexes differ petrologically and/or volumetrically from

417-562: A few small remnants of their original surface remain. The degree of erosion becomes less pronounced on those that have more recently formed. Several cinder cones dotting the plateau surface rise up to 460 metres (1,500 feet) above the surrounding terrain , most of which occur in three lava fields. The Desolation Lava Field on the northern slope of Mount Edziza contains 10 cinder cones, namely Eve Cone , Storm Cone , Moraine Cone , Williams Cone , Sleet Cone , Twin Cone , Sidas Cone and

556-540: A long and narrow graben -like depression possibly linked to volcanism of the volcanic complex . The eastern edge of the valley is bounded by north-trending faults , one of which has been traced for more than 24 kilometres (15 miles). This fault shows signs of having been active contemporaneously with volcanism of the MEVC; it has vertically displaced Holocene basalt flows by 15 to 20 metres (50 to 70 feet) and older basalt flows by 91 to 122 metres (299 to 400 feet), such that

695-521: A nearly continuous record of activity dating from the Miocene . It covers 1,000 square kilometres (390 square miles) and comprises 665 cubic kilometres (160 cubic miles) of volcanic material, making it the second largest eruptive centre in the NCVP after Level Mountain. The MEVC is also the second most long-lived eruptive centre in the NCVP after Level Mountain, having started erupting at least 7.4 million years ago. The eruption sequence and style of

834-648: A possibility at any time of the year. The closest weather stations to the MEVC are located at Telegraph Creek and Dease Lake , which lie about 40 kilometres (25 miles) to the northwest and 85 kilometres (53 miles) to the northeast, respectively. Meteorological data from the Telegraph Creek and Dease Lake weather stations suggest that the MEVC area has a temperature gradient of around −1.5 degrees Celsius (29.3 degrees Fahrenheit) per 1,000-metre (3,300-foot) increase in elevation. The data also suggest that precipitation likely increases with altitude. At Mess Creek,

973-616: A potential hazard as they have formerly dammed the Klastline and Stikine rivers, the latter of which contains a major salmon fishery. Another potential hazard at the MEVC is the ignition of wildfires by eruptions as the surrounding area has vegetation. An eruption under the ice cap would possibly produce floods or lahars that could flow into the Stikine or Iskut rivers, potentially destroying salmon runs and threatening river bank villages. Like other volcanic complexes in Canada,

1112-532: 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

1251-516: 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

1390-454: 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

1529-543: A steep-walled pyramidal peak with active cirques on all of its sides. The Spectrum Range has an elevation of 2,430 metres (7,970 feet) and consists of a nearly circular, more than 10-kilometre-wide (6.2-mile) dome with a thickness of up to 650 metres (2,130 feet). Armadillo Peak represents the eroded remains of a small caldera whose 2,194-metre (7,198-foot) summit is capped by a 180-metre-thick (590-foot) sequence of ponded lava flows. Various stages of erosion have modified these central volcanoes; in some cases, only

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1668-486: A study of aenigmatite crystals which occur in peralkaline rocks of the MEVC. Yagi Ridge in the Spectrum Range was named in honour of Kenzō Yagi who traversed this ridge with Souther during their geological studies. During his last year of serious field work in 1992, Souther published an extensive bulletin on his work entitled The Late Cenozoic Mount Edziza Volcanic Complex, British Columbia which highlighted

1807-550: A warning for a large eruption; the system might detect activity only once the complex has started erupting. If the MEVC 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 MEVC lies within

1946-417: A wide variety of volcanic rocks that comprise 13  geological formations . The most recent eruptions took place in the last 11,000 years but none of them have been precisely dated. Current activity occurs exclusively in the form of hot springs which exist along the western side of the volcanic complex. Future eruptions are likely to impact local streams and cause wildfires. Several streams surround

2085-401: 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). Mount Edziza volcanic complex The Mount Edziza volcanic complex ( / ə d ˈ z aɪ z ə / əd-zy-zə ; abbreviated MEVC )

2224-496: Is a crescent-shaped mountain ridge east of the Kitsu Plateau and just north of Artifact Creek . Just south of Artifact Ridge and Artifact Creek is Obsidian Ridge , a mountain ridge containing high-quality obsidian . Destell Pass is a narrow rock cleft northwest of Artifact Ridge that provides access between the broad upland valleys of Artifact Creek and Raspberry Creek . It is one of two named mountain passes in

2363-509: Is a group of volcanoes and associated lava flows in northwestern British Columbia , Canada. Located on the Tahltan Highland , it is 40 kilometres (25 miles) southeast of Telegraph Creek and 85 kilometres (53 miles) southwest of Dease Lake . The complex encompasses a broad, steep-sided lava plateau that extends over 1,000 square kilometres (390 square miles). Its highest summit is 2,786 metres (9,140 feet) in elevation, making

2502-399: Is a prominent west-facing cliff while Kaia Bluff is a steep-sided hill. On the northwestern side of Raspberry Pass is an isolated, flat-topped hill with steep sides called Gnu Butte . The Mess Creek Escarpment is a long, often cliff-like feature forming the western edge of the MEVC. It runs along the eastern side of Mess Creek and exposes thick, flat-lying lava flows. Artifact Ridge

2641-554: 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

2780-487: Is drained by many outlet glaciers that spread in broad lobes onto the Big Raven Plateau whereas the eastern side is drained by distributary glaciers that drape down steep slopes to form discontinuous icefalls . Five officially named glaciers are situated at the northern and southern ends of the MEVC. Idiji Glacier lies southeast of Mount Edziza on the eastern side of the MEVC. At the head of Nagha Creek in

2919-589: 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

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3058-899: Is instead translated as "kutlves" in the Tahltan language. An explanation listed in the BC Parks brochure is that Edziza means "cinders" in the Tahltan language. Another explanation proposed by Canadian volcanologist Jack Souther is that Edziza is a corruption of Edzerza, the name of a local Tahltan family. The geomorphology of the MEVC is in some ways similar to that of the Eyjafjallajökull volcano in Iceland. This includes its overall elongated structure, its flanking basaltic lava fields and its summit ice cap surrounded by silica -rich volcanic rocks. The elongated structure of

3197-598: Is more widespread than previously thought. On the basis of similar rock types and lithologic associations, six new uranium-lead zircon dates , and the common intrusive relationship with 184–195 million year old plutons , the Stikine assemblage is correlated with the Boundary Ranges suite, a metamorphosed Paleozoic volcanic assemblage exposed in the Tagish Lake area, north of the Taku River and south of

3336-514: Is one of seven ecosections comprising the Boreal Mountains and Plateaus Ecoregion , a large ecological region of northwestern British Columbia encompassing high plateaus and rugged mountains with intervening lowlands . Boreal forests of black and white spruce occur in the lowlands and valley bottoms of this ecoregion whereas birch , spruce and willow form forests on the mid-slopes. Extensive alpine altai fescue covers

3475-469: Is the main lake bordering the northern side of the MEVC while Mess Lake is the main lake bordering the western side of the MEVC. Southeast of the MEVC is 180 Lake, so-named because it is large enough for the Cessna 180 Skywagon to safely operate. The southern end of the MEVC is flanked by Arctic Lake which gets its name from the surrounding barren and treeless landscape. Two small lakes are named on

3614-669: Is the most recently defined volcanic province in the Western Cordillera . It has formed due to extensional cracking of the North American continent—similar to other on-land extensional volcanic zones, including the Basin and Range Province and the East African Rift . Although taking its name from the Western Cordillera, this term is a geologic grouping rather than a geographic one. The southmost part of

3753-513: Is the southernmost of the three subplateaus; it consists of a nearly flat upland containing Outcast Hill , Tadekho Hill , Wetalth Ridge , Nahta Cone, Source Hill , Thaw Hill and Exile Hill . In the north fork of Tenchen Creek is Cinder Cliff , a 210-metre-high (690-foot) barrier of volcanic rocks. Koosick Bluff and Ornostay Bluff are just southwest of Mount Edziza near the head of Sezill Creek . Northwest and east of Coffee Crater are Hoia Bluff and Kaia Bluff, respectively. Hoia Bluff

3892-431: Is volcanically dormant but it still remains hydrothermally active. Four hot spring areas are found along the western flank of the MEVC at Mess Lake, Mess Creek, Elwyn Creek and Sezill Creek, the latter three of which have recorded water temperatures of 42.5 degrees Celsius (108.5 degrees Fahrenheit), 36 degrees Celsius (97 degrees Fahrenheit) and 46 degrees Celsius (115 degrees Fahrenheit), respectively. Discharge at

4031-614: The British Columbia Coast , making Edziza obsidian the most widely distributed obsidian in western North America. Edziza obsidian from the Hidden Falls archaeological site in Alaska has yielded a hydration date of 10,000 years; this suggests the MEVC was being exploited as an obsidian source soon after ice sheets of the last glacial period retreated. The MEVC continues to be an important cultural resource for

4170-630: 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

4309-650: 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

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4448-598: The Iskut River . A northerly-trending, elliptical, composite shield volcano consisting of multiple flat-lying lava flows forms the plateau. The MEVC is surrounded on the east by the Skeena Mountains and the Klastline Plateau while to the west it is flanked by the Coast Mountains . It lies on the eastern edge of the Tahltan Highland , a southeast-trending upland area extending along

4587-505: 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 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

4726-512: The Stikine River and Taku River areas. In contrast, Mesozoic Stikinia rocks form a near-continuous belt that extends much farther to the north, leading some authors to question the nature of the unexposed Paleozoic basement north of the Taku River area. The following correlations have significant implications for tectonic reconstructions of the northern Cordillera because they suggest that Stikinia's Paleozoic volcanic-sedimentary basement

4865-700: The Stikine Volcanic Belt , is a geologic province defined by the occurrence of Miocene to Holocene volcanoes in the Pacific Northwest of North America . This belt of volcanoes extends roughly north-northwest from northwestern British Columbia and the Alaska Panhandle through Yukon to the Southeast Fairbanks Census Area of far eastern Alaska , in a corridor hundreds of kilometres wide. It

5004-740: The University of Wisconsin–Milwaukee , Ian Spooner of Acadia University , J. Osborn of the University of Calgary , Kirstie Simpson of the Geological Survey of Canada and Bill McIntosh of the New Mexico Institute of Mining and Technology . Five students conducted studies at the MEVC in 2007, namely Chira Endress of Dickinson College, Jeff Hungerford of the University of Pittsburgh, Courtney Haynes of Dickinson College, Alex Floyd of Dickinson College and Kristen LaMoreaux of

5143-505: The Yukon Telegraph Trail for maintenance. One of these maintenance cabins existed at Raspberry Creek in the central portion of the MEVC. The Yukon Telegraph Line and trail were maintained until 1936 when they were abandoned with the advent of radio communication. Remnants of this telegraphy system include collapsed cabins, telegraph wire and a few telegraph poles. The MEVC is one of the best-studied volcanic centres in

5282-461: 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

5421-489: 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

5560-449: The timberline where grizzly bears are occasionally seen. The alpine and subalpine zones between Mount Edziza and the western escarpment contain small herds of Osborn caribou . The western escarpment, the Spectrum Range and the eastern, western and southern flanks of Mount Edziza contain mountain goats and stone sheep . Other mammals in the area include moose, black bears and wolves . Several species of birds are also present in

5699-602: 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

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5838-615: The 1950s, the most detailed studies having been conducted in the 1960s. A large provincial park , which can only be accessed by aircraft or by a network of footpaths , dominates the MEVC. The Mount Edziza volcanic complex is sometimes referred to as the Mount Edziza–Spectrum Range complex or the Mount Edziza Plateau. Stratigraphically , it has also been referred to as the Mount Edziza Group or

5977-514: The Canadian Cordillera. By 1970, Souther and his assistant Maurice Lambert had established that episodic eruptions of alkali basalt and silicic peralkaline lavas had taken place at the MEVC over a timespan of at least 10 million years. They had also established that volcanism of the MEVC was accompanied by east–west extension and incipient rifting of Earth's crust . In 1974, Souther and Japanese volcanologist Kenzō Yagi conducted

6116-491: 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

6255-660: 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

6394-686: The Edziza Group. A number of explanations have been made regarding the origin of the name Edziza. A 1927 report by J. Davidson of the British Columbia Land Surveyors claims that Edziza means "sand" in the Tahltan language , referring to the deep volcanic ash deposits or pumice -like sand covering large portions of the Big Raven Plateau around Mount Edziza . According to David Stevenson of University of Victoria 's Anthropology Department, "sand" or "dust"

6533-553: 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

6672-617: The Holocene. Several eruptions of the latest magmatic cycle have not been quantitatively dated. Instead, a Holocene age is inferred because their eruptive products do not show evidence of having been glaciated by the Cordilleran Ice Sheet , which retreated from the area about 11,000 years ago. Therefore, many of these inferred Holocene eruptions may have occurred as early as the time of glacial retreat. An eruption recurrence interval of 379 years has been calculated for

6811-633: 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

6950-494: The MEVC a high threat volcanic complex because it has had the highest eruption rate in Canada throughout the Holocene. However, its extremely remote location makes it less hazardous than volcanoes in southwestern British Columbia. MEVC trachyte and rhyolite have silica-rich compositions that are comparable to those associated with the most powerful eruptions around the world; parts of northwestern Canada could be affected by an ash column if an explosive eruption were to happen at

7089-580: The MEVC a potential high-temperature geothermal resource area but it does not warrant subsurface exploration due to its remote location. The Mess Lake Hot Springs are situated near the southeastern corner of Mess Lake. They lie at an elevation of 760 metres (2,490 feet) and have created massive deposits of tufa that cover more than 120 hectares (300 acres). These springs had a vigorous flow of warm water in 1965, but by 1992 they were discharging water below human body temperature. The Mess Creek Hot Springs 7 kilometres (4.3 miles) south of Mess Lake are on

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7228-557: The MEVC are drained by tributaries of the Iskut River. This includes Ball Creek which flows to the south from the southeastern side of the Spectrum Range, More Creek which flows to the southeast from the southern side of the Spectrum Range and the Little Iskut River which flows to the southeast from the southeastern side of the Spectrum Range. The only named tributary of Ball Creek is Chachani Creek which flows to

7367-444: The MEVC are mafic alkali basalts and hawaiites, which comprise about 60% of the volcanic complex. MEVC hawaiites are thought to be the product of partial fractional crystallization and the accumulation of feldspar inside rising columns of mantle -derived alkali basaltic magma. Volcanic rocks of intermediate composition such as benmoreite , trachybasalt , mugearite and tristanite are present in relatively small volumes and are

7506-405: The MEVC by dividing 11,000 years by the number of demonstrable Holocene eruptions, of which there are at least 29. This would make the MEVC the most active eruptive centre in Canada throughout the Holocene. It is also one of the most widespread areas of recent volcanism in Canada. Eruptions have occurred subaqueously , subglacially and subaerially throughout the long eruptive history of

7645-465: The MEVC is about 65 kilometres (40 miles) long and 20 kilometres (12 miles) wide. It comprises a broad, steep-sided, intermontane plateau that rises from a base elevation of 760 or 816 metres (2,500 or 2,675 feet). Its sides tower 760 metres (2,500 feet) above adjacent valleys that serve as drainageways for several streams. The edges of the plateau have been deeply incised by creeks that flow eastward and westward into Mess Creek , Kakiddi Creek and

7784-484: The MEVC is not monitored closely enough by the Geological Survey of Canada 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 complex. It may sense an increase in seismic activity if the MEVC becomes highly restless, but this may only provide

7923-677: The MEVC is the Stikinia terrane , a Paleozoic and Mesozoic suite of volcanic and sedimentary rocks that accreted to the continental margin of North America during the Jurassic . Rocks of Paleozoic age such as limestone , bedded tuff and volcanic rocks of intermediate composition underlie the western and southern portions of the MEVC. Mesozoic rocks underlie most of the MEVC and include andesite , basaltic andesite , volcanic sandstone , siltstone , shale , greywacke , limestone and chert . The youngest basement rocks are those of

8062-408: The MEVC overlooks a drainage divide that lies in a broad hummocky lowland. Its upper eastern half is drained by tributaries of Kakiddi Creek. This includes Nido Creek , Tenchen Creek and Tennaya Creek which flow to the northeast from the eastern side of Mount Edziza, Shaman Creek and Sorcery Creek which flow to the east and north from near Kaia Bluff and Tsecha Creek which flows to

8201-546: The MEVC the highest of four large complexes in an extensive north–south trending volcanic region. It is obscured by an ice cap characterized by several outlet glaciers that stretch out to lower altitudes. The MEVC consists of several types of volcanoes , including stratovolcanoes , shield volcanoes , cinder cones and lava domes . These volcanoes have formed over the last 7.5 million years during five cycles of magmatic activity which spanned four geologic epochs . Volcanic eruptions during these magmatic cycles produced

8340-781: The MEVC, along with its chemistry, mineralogy and isotopic composition, is similar to continental peralkaline volcanism at the Rainbow Range of central British Columbia, the Afar Depression of East Africa and parts of the Great Basin of the western United States. Five cycles of magmatic activity created the MEVC; one in the Miocene, one in the Plio-Pleistocene , two in the Pleistocene and one in

8479-615: The MEVC, many of which drain the flanks of the volcanic complex. They include the Little Iskut River along the southeastern flank, Kakiddi Creek along the northeastern flank, the Klastline River along the northern flank and Mess Creek along the western flank. The valleys of these streams contain several species of trees, including white spruce , trembling aspen and lodgepole pine . Animal species such as birds, rodents, bears, sheep, goats, moose and caribou inhabit

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8618-494: The MEVC, the other being Raspberry Pass between the heads of Bourgeaux Creek and Raspberry Creek. Raspberry Pass is a broad east–west valley separating the Spectrum Range in the south from the Mount Edziza area in the north. The eastern side of the MEVC is flanked by Mowdade Lake, Kakiddi Lake , Mowchilla Lake and Nuttlude Lake in Kakiddi Valley; the last three drain north into the Klastline River . Buckley Lake

8757-483: The MEVC. Ash columns can drift for thousands of kilometres downwind and often become increasingly spread out over a larger area with increasing distance from an erupting vent. The MEVC lies under a major air route from Vancouver , British Columbia to Whitehorse , Yukon, suggesting the volcanic complex poses a potential threat to air traffic. Volcanic ash reduces visibility and can cause jet engine failure, as well as damage to other aircraft systems. Lava flows are also

8896-785: The MEVC. Interactions between ice and volcanism are well-documented at the MEVC, occurring in seven of the 13 geological formations comprising the volcanic complex. This includes the Pyramid, Ice Peak, Pillow Ridge, Edziza, Arctic Lake, Klastline and Big Raven formations which have all formed within the last two million years. Volcano-ice interactions at these formations is represented by pillow lava , tuff breccia , hyaloclastite , glacial till interbedded with lava flows, and massive lava with well-developed slender columnar joints . The MEVC has been scoured by regional glaciations at least twice during its eruptive history, as well as several smaller advances of local alpine glaciers. The MEVC

9035-399: The MEVC. This rapid glacial recession is apparent from the lack of vegetation on the barren, rocky ground between the glaciers and their trim lines which are up to 2 kilometres (1.2 miles) apart. The MEVC has been extensively modified by local and regional glaciations as evidenced by the existence of drumlins and glacial striations , which record ice movement to the north-northwest across

9174-579: 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

9313-496: The NCVP has more, and larger, volcanoes than does the rest of the NCVP; further north it is less clearly delineated, describing a large arch that sways westward through central Yukon. 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

9452-611: The NCVP. It was identified by the mapping program of Operation Stikine in 1956 along with Level Mountain, the Iskut-Unuk River Cones and many smaller volcanoes in the Canadian Cordillera . Their identification played a role in the closing of Canada's gap in the Ring of Fire because it allowed them to be added on the world volcanic map. The mapping program of Operation Stikine, masterminded by Jack Souther,

9591-414: 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

9730-415: 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

9869-532: 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

10008-669: 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

10147-547: 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

10286-538: 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 the past 1.8 million years. At least three of them have erupted in

10425-416: 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

10564-440: 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

10703-510: 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

10842-419: 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

10981-552: 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

11120-417: 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,

11259-438: 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

11398-475: 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

11537-462: 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

11676-755: The Sezill Creek, Elwyn Creek and Mess Lake hot springs may be linked to shallow hydrothermal systems driven by residual magmatic heat as they are adjacent to recently active eruptive centres. In contrast, the Mess Creek Hot Springs may be discharging from a deeply circulating hydraulic system along a major fault on the western side of Mess Creek valley. Estimated subsurface temperatures, as derived from geothermometers , are 177 degrees Celsius (351 degrees Fahrenheit) based on silica concentrations and 227 degrees Celsius (441 degrees Fahrenheit) based on sodium - potassium - calcium ratios. This makes

11815-536: The Sloko Group which comprises Early Tertiary intermediate calc-alkaline volcanic rocks and related subvolcanic plutons . These rocks were tilted, cut by normal faults and heavily eroded before volcanism began at the MEVC in the Late Miocene , such that the volcanic complex was built on a mature, gently rolling Tertiary erosion surface . The MEVC lies on the eastern shoulder of Mess Creek valley,

11954-481: The Spectrum Range and the Armadillo Highlands as part of the neoglaciation . As these glaciers advanced they built up to 18-metre-high (59-foot) terminal moraines on the plateau surface which comprise the trim lines of the current mountain glaciers. The present trend towards a more moderate climate put an end to the neoglacial period in the 19th century, resulting in rapid glacial recession throughout

12093-577: The Spectrum Range in 1988. The MEVC 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

12232-452: The Spectrum Range. Walkout Creek is the only named tributary of Raspberry Creek; it flows west in a canyon west of the Armadillo Highlands and also contains only one named tributary, Flyin Creek , which flows northwest from near the west side of Cache Hill . The only named tributary of Taweh Creek is Sezill Creek which flows northwest in a canyon southwest of Mount Edziza. To the east,

12371-561: The Stikine River watershed . To the west, Mess Creek flows north along the Mess Creek Escarpment inside a broad valley paralleling the MEVC. It then flows northwest into the Stikine River near the community of Telegraph Creek . Several short tributaries of Mess Creek drain the western half of the MEVC where they have cut steep-sided canyons into the volcanic plateau. This includes Crayke Creek which flows to

12510-585: The Tahltan people. In 2021, Chad Norman Day, president of the Tahltan Central Government, said "Mount Edziza and the surrounding area has always been sacred to the Tahltan Nation. The obsidian from this portion of our territory provided us with weaponry, tools and trading goods that ensured our Tahltan people could thrive for thousands of years." Along the western side of the MEVC and through its central portion at Raspberry Pass are

12649-454: The Taku terrane in southeast Alaska, and undivided metamorphic rocks in west-central British Columbia. Differences in the isotopic signatures of these rocks may reflect along-strike changes in the character of the basement rocks of the late Paleozoic Stikinia volcanic arc. Northern Cordilleran Volcanic Province The Northern Cordilleran Volcanic Province ( NCVP ), formerly known as

12788-655: 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

12927-584: 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

13066-742: The Tracy Arm terrane in its hanging wall. This correlation also implies that the late Paleozoic basement to the Mesozoic Stikinia arc is not a continental margin assemblage, at least as far north as the British Columbia–Yukon border, and possibly farther. The Boundary Ranges suite, and therefore the Stikine assemblage, are also tentatively correlated with parts of the Yukon–Tanana Terrane in Yukon ( Aishihik Lake area), parts of

13205-402: The University of Pittsburgh. Much of the MEVC was designated as a provincial park in 1972 to showcase its geological and geothermal features. A 101,171-hectare (250,000-acre) recreation area surrounding the 132,000-hectare (330,000-acre) park was also established in 1972. In 1989, Mount Edziza Provincial Park roughly doubled in size when 96,770 hectares (239,100 acres) was annexed from

13344-599: The Yukon–British Columbia border. The recognition of the Boundary Ranges suite and the Jurassic plutons that intruded it (Tagish Lake suite) as part of Stikinia has implications for the age and character of the Stikinia–Tracy Arm terrane boundary because the Boundary Ranges and Tagish Lake suites form the footwall of a major Middle Jurassic shear zone that carried the continental margin–like rocks of

13483-467: The area, including scaup , owls , goldeneye , grebes , gyrfalcons , white-winged scoters , ravens , grouse and ptarmigans . The area between Buckley Lake and Telegraph Creek contains peat meadows , shrub fields and wet grasslands . It is characterized by long, severe winters with short growing seasons and deeply frozen soils. The Mess Creek, Kakiddi and Klastline valleys are intermixed with white spruce, trembling aspen and lodgepole pine ,

13622-414: The area. Warm summers and cold, snowy winters characterize the climate at the MEVC; snow and ice remain on the highest volcanoes year-round. Indigenous peoples have lived adjacent to the MEVC for thousands of years. Historically, the local Tahltan people used volcanic glass from the MEVC to make tools and weaponry. Intermittent geological work has been carried out at the volcanic complex since at least

13761-632: 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

13900-517: 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

14039-558: The extreme southern end of the MEVC, Kana Cone on the extreme northern flank of the MEVC and two unnamed cones in Walkout Creek valley. The MEVC contains three named subplateaus, the largest and northernmost of which is the Big Raven Plateau. Its dominant feature is Mount Edziza which rises from within the middle of the plateau. Two lava fields are present on the Big Raven Plateau; the Desolation Lava Field at

14178-536: 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

14317-431: The fault zone contain pressure ridges 10 to 40 centimetres (3.9 to 15.7 inches) high and 50 to 100 metres (160 to 330 feet) long, suggesting these faults are still active. This was confirmed by a local trapper in 1992 who noted that new pressure ridges appeared each year. The MEVC was originally subdivided into 15 geological formations , two of which are no longer used: The MEVC is a highly active volcanic system with

14456-413: The importance and size of the MEVC. The volcanic complex has since received very few geological studies. A three-year period of field studies conducted at the MEVC around 2007 focused on using volcano-ice interactions to constrain paleo-environmental conditions. The project was a collaboration between Ben Edwards of Dickinson College , Ian Skilling of the University of Pittsburgh , Barry Cameron of

14595-637: 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

14734-538: 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

14873-574: The latter two of which occur in drier areas. Balsam poplar grows on delta soils and near lakes and creeks. The MEVC plateau is characterized by alpine and subalpine vegetation zones. The MEVC was covered by a regional ice sheet during the Pleistocene which receded and advanced periodically until about 11,000 years ago when deglaciation was essentially complete in a steadily warming climate. This warming trend ceased about 2,600 years ago, causing glaciers to advance from Mount Edziza, Ice Peak,

15012-424: 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

15151-509: The low-yield strength of the highly fractured, poorly consolidated rocks comprising the MEVC. Most peaks greater than 2,130 metres (6,990 feet) in elevation have glaciers. Small separate glaciers are largely restricted to the southern half of the MEVC where they occur in the Spectrum Range, on Armadillo Peak and elsewhere. In contrast, Mount Edziza and Ice Peak are obscured by a relatively large ice cap that covers an area of 70 square kilometres (27 square miles). The western side of this ice cap

15290-469: The mean annual temperature is probably around −1 degree Celsius (30 degrees Fahrenheit) while the annual precipitation likely amounts to 400 millimetres (16 inches) of snow and rain. The mean annual temperature at an elevation of 1,390 metres (4,560 feet) is likely about −1 to −5 degrees Celsius (30 to 23 degrees Fahrenheit) where annual precipitation amounts to approximately 400 to 500 millimetres (16 to 20 inches). Arctic ground squirrels are abundant above

15429-571: 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

15568-510: The northeast from near Williams Cone. Shaman Creek contains one named tributary, Chakima Creek , which flows to the east and north. The rapidly eroding headwalls and steep spurs on the eastern side of the MEVC have deposited glacial and landslide debris into these tributaries. Transportion of this debris into Kakiddi Valley has produced several large alluvial fans behind which Kakiddi Lake, Mowchilla Lake, Mowdade Lake and Nuttlude Lake have formed. The lower eastern half and south end of

15707-554: The northern end of the plateau covers more than 150 square kilometres (58 square miles) whereas the Snowshoe Lava Field covers about 40 square kilometres (15 square miles) at the southern end of the plateau. At the northwestern end of the Spectrum Range is the Kitsu Plateau ; its dominant feature is the even smaller Mess Lake Lava Field which covers 18 square kilometres (6.9 square miles). The Arctic Lake Plateau

15846-400: 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 the Pacific Ring of Fire,

15985-652: The remains of the Yukon Telegraph Line. This was a nearly 3,000-kilometre-long (1,900-mile) telegraphy system built by the Dominion Government Telegraph Service between 1897 and 1901 to send messages between Ashcroft, British Columbia in the south to Dawson City , Yukon in the north. A trail built to serve the line extended along much of its length and provided a route to the Yukon gold fields. Log cabins housing two men were built every 32 kilometres (20 miles) along

16124-627: The rest of the NCVP. Heart Peaks, Level Mountain and the MEVC are the largest NCVP centres by volume, the latter two having experienced volcanism for a much longer timespan than any other NCVP centre. Level Mountain, Hoodoo Mountain and the MEVC are the only NCVP centres that contain volcanic rocks of both mafic and intermediate to felsic composition. The highest of the four complexes is the MEVC 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). The most voluminous rocks comprising

16263-407: The result of alkali basaltic magma having undergone fractional crystallization in magma chambers on a longer timespan. Felsic peralkaline rocks such as trachyte, comendite and pantellerite form about 40% of the MEVC; they are the product of prolonged fractional crystallization of mantle-derived basaltic magma in magma chambers and mainly comprise lava domes and central volcanoes. Underlying

16402-414: 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

16541-563: 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

16680-640: The southeast from the eastern end of the Arctic Lake Plateau. Tributaries of the Little Iskut River include Stewbomb Creek , which flows eastwards from the eastern side of the Spectrum Range, and Bourgeaux Creek which flows to the east from Raspberry Pass. The only named tributary of Stewbomb Creek is Artifact Creek which flows to the southeast between Artifact Ridge and Obsidian Ridge. Bourgeaux Creek contains one named tributary, Gerlib Creek , which flows southwards from between Tadeda Peak and Armadillo Peak. Several small, unnamed streams drain

16819-428: The southern portion of the MEVC. At the head of the Little Iskut River is Little Ball Lake , also called Kounugu Lake after the guardian of fresh water in Tahltan folklore . It lies immediately south of Kounugu Mountain in the Spectrum Range and east of Ball Creek . Little Arctic Lake lies northeast of Arctic Lake near the northeastern flank of Wetalth Ridge. The MEVC is drained on all sides by streams within

16958-540: 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

17097-404: 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

17236-497: The southwest, Elwyn Creek which flows to the west, Kitsu Creek which flows to the northwest, Raspberry Creek which flows to the northwest, Tadekho Creek which flows to the northwest and Taweh Creek which flows to the northwest. Many of these Mess Creek tributaries also contain tributaries; the only named tributary of Elwyn Creek is Kadeya Creek which flows northwest from Mount Edziza . Kitsu Creek contains one named tributary, Nagha Creek , which flows northwest from

17375-533: 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

17514-489: 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

17653-578: The three Triplex Cones. Five named cones occur in the Snowshoe Lava Field on the southwestern flank of Ice Peak: Tennena Cone , Keda Cone , Coffee Crater , Cocoa Crater and The Saucer . The Ash Pit is the only named cinder cone in the Mess Lake Lava Field which lies at the south-central end of the MEVC. Isolated cinder cones include Icefall Cone and Ridge Cone on the eastern slope of Mount Edziza, Nahta Cone at

17792-482: The traditional territory of the Tahltan people which covers an area of more than 93,500 square kilometres (36,100 square miles). Historically, the MEVC was a significant source of obsidian for the Tahltan people. This volcanic glass was used in the manufacturing of projectile points and cutting blades which were widely traded throughout the Pacific Northwest . Obsidian from the MEVC has been recovered from archaeological sites in Alaska, Yukon, western Alberta and along

17931-469: The upper slopes but barren rock is abundant at higher elevations. Four central volcanoes dominate the MEVC, Mount Edziza being the highest with an elevation of 2,786 metres (9,140 feet). It is a large ice-covered stratovolcano rising well above the general level of the Tahltan Highland. Ice Peak is a composite stratovolcano 2,500 metres (8,200 feet) in elevation that has been reduced to

18070-481: 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 is part of an area of intensive earthquake and volcanic activity around the Pacific Ocean called the Pacific Ring of Fire . However,

18209-515: 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

18348-442: The western portion of the Spectrum Range is Nagha Glacier. Tenchen Glacier is a debris-covered glacier on the eastern side of Mount Edziza at the head of Tenchen Creek. South of Mount Edziza lies Tencho Glacier , the largest glacier of the MEVC. Tennaya Glacier lies at the head of Tennaya Creek on the southeastern side of Mount Edziza. The informally named Yeda Glacier existed at the head of Ball Creek south of Yeda Peak in

18487-402: The western portion of the plateau. Evidence of ice stagnation is present in the form of outflow channels, eskers , kames , kettles and morainal ridges on the northern side of the MEVC adjacent to Buckley Lake. Deglaciation of unstable and oversteepened valley walls has caused several landslides in the geologic past, especially along the Mess Creek Escarpment. This instability is attributed to

18626-567: The western side of Mess Creek where they attain an elevation of 760 metres (2,490 feet). Along the banks of Elwyn Creek at an elevation of 1,440 metres (4,720 feet) are the Elwyn Hot Springs which have created thick tufa deposits. The Taweh Hot Springs extend 0.5 kilometres (0.31 miles) along Sezill Creek at an elevation of 1,310 metres (4,300 feet) and emit thermal waters containing carbon dioxide ; extensive tufa deposits occur at these springs. Natural Resources Canada considers

18765-747: The western side of the Stikine Plateau . This upland area lies between the Taku River in the north, the Boundary Ranges in the west and the head of the Iskut River in the east. The width of the Tahltan Highland varies from about 8 kilometres (5.0 miles) in the north to about 48 kilometres (30 miles) in the south where the Stikine River crosses the highland . The MEVC is in the Southern Boreal Plateau Ecosection which consists of several upland summits as well as wide river valleys and deeply incised plateaus. It

18904-403: The western side of the fault has moved downward. The downthrowing of this fault during the Holocene may have been due to the draining of magma chambers following eruptions at the MEVC. The existence of peralkaline rocks at the MEVC and the presence of normal faults along Mess Creek valley support the conclusion that the MEVC lies in an area of continental rifting. Many tufa terraces along

19043-545: The youthful northern side of the MEVC. They flow north into the Klastline River and contain shallowly incised channels . The surrounding area is characterized by warm summers and cold, snowy winters; Mount Edziza itself is covered by snow year-round. Temperatures are warmest in mid-summer during the day when they may hit the 30 degrees Celsius (86 degrees Fahrenheit) range. However, temperatures can drop below freezing during summer nights, making snow or freezing rain

19182-408: Was carried out over the Stikine River area using a Bell helicopter. Souther began detailed mapping of the MEVC in 1965 when he was given the job of working on the volcanic complex by the Geological Survey of Canada. Japanese volcanologist Hisashi Kuno visited the MEVC with Souther in 1966; Kuno Peak in the Spectrum Range was named in his honour. A three-month period of earthquake monitoring

19321-493: Was conducted at the MEVC in 1968 after geologists of the Geological Survey of Canada suggested that there may still be magma movement under the volcanic complex. About 20  microearthquakes potentially associated with the MEVC were recorded by seismographs installed at Buckley Lake and Nuttlude Lake, but a seismological analysis suggested that they were of non-volcanic origin. The microearthquakes had magnitudes of around 0.5 which typically occur in many areas throughout

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