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153-750: Mount Edziza ( / ə d ˈ z aɪ z ə / əd-zy-zə ), known to the local Tahltan people as Tenh Dẕetle ( / ˈ t ɛ n ˌ θ ɛ t . l ʌ h / ten-thet-luh ), is a volcanic mountain in Cassiar Land District of northwestern British Columbia , Canada. It is located on the Big Raven Plateau of the Tahltan Highland which extends along the western side of the Stikine Plateau . Mount Edziza has an elevation of 2,786 metres (9,140 feet), making it

306-524: A British Airways Boeing 747-236B ( Flight 9 ) flew through the ash cloud from the eruption of Mount Galunggung , Indonesia resulting in the failure of all four engines. The plane descended 24,000 feet (7,300 m) in 16 minutes before the engines restarted, allowing the aircraft to make an emergency landing. On 15 December 1989, a KLM Boeing 747-400 ( Flight 867 ) also lost power to all four engines after flying into an ash cloud from Mount Redoubt, Alaska . After dropping 14,700 feet (4,500 m) in four minutes,

459-530: A coalbed methane mining project planned by Royal Dutch Shell . The Sacred Headwaters (Klappan Valley) is home to the headwaters of the Nass , Skeena and Stikine Rivers . Not only do these rivers provide a home to important salmon stocks, Tahltan oral history holds that these headwaters are the place where the earth was first created and where Talhtan culture began. According to the Klabona Keepers,

612-904: A hydration date of 10,000 years for Edziza obsidian , suggesting the area was being exploited as an obsidian source soon after ice sheets of the Last Glacial Period retreated. Two obsidian flows of the Pyramid Formation occur on The Pyramid and are exposed as two outcrops; they were quarried as evidenced by the occurrence of Pyramid obsidian in at least five archaeological sites outside of Tahltan territory. The Ice Peak Formation contains two obsidian flows on Sorcery Ridge that were also exploited as an obsidian source. Sorcery Ridge obsidian occurs in at least two archaeological sites outside of Tahltan territory. In or before 1974, two Tahltan men named Johnny Edzerza and Hank Williams were killed in an avalanche while they were crossing

765-485: 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 and elsewhere along the volcanic complex as a part of the neoglaciation . The present trend towards a more moderate climate put an end to

918-489: 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 the Mount Edziza Recreation Area . In doing so, the recreation area was greatly reduced in size to around 4,000 hectares (9,900 acres). This small remnant of

1071-595: A characteristically dark coloured ash containing ~45–55% silica that is generally rich in iron (Fe) and magnesium (Mg). The most explosive rhyolite eruptions produce a felsic ash that is high in silica (>69%) while other types of ash with an intermediate composition (e.g., andesite or dacite ) have a silica content between 55 and 69%. The principal gases released during volcanic activity are water , carbon dioxide , hydrogen , sulfur dioxide , hydrogen sulfide , carbon monoxide and hydrogen chloride . The sulfur and halogen gases and metals are removed from

1224-448: A clay matrix. Particle surfaces are often coated with aggregates of zeolite crystals or clay and only relict textures remain to identify pyroclast types. The morphology (shape) of volcanic ash is controlled by a plethora of different eruption and kinematic processes. Eruptions of low-viscosity magmas (e.g., basalt) typically form droplet shaped particles. This droplet shape is, in part, controlled by surface tension , acceleration of

1377-659: 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. A wide variety of volcanic rocks comprise Mount Edziza, the main mafic rock being basalt which comprises lava flows, cinder cones and ash beds on

1530-856: A few millimeters requires removal before airports can resume full operations. Ash does not disappear (unlike snowfalls) and must be disposed of in a manner that prevents it from being remobilised by wind and aircraft. Ash may disrupt transportation systems over large areas for hours to days, including roads and vehicles, railways and ports and shipping. Falling ash will reduce the visibility which can make driving difficult and dangerous. In addition, fast travelling cars will stir up ash, generating billowing clouds which perpetuate ongoing visibility hazards. Ash accumulations will decrease traction, especially when wet, and cover road markings. Fine-grained ash can infiltrate openings in cars and abrade most surfaces, especially between moving parts. Air and oil filters will become blocked requiring frequent replacement. Rail transport

1683-599: A forward-facing surface, that are tuned to detect volcanic ash. This system can detect ash concentrations of <1 mg/m to > 50 mg/m , giving pilots approximately 7–10 minutes warning. The camera was tested by the easyJet airline company, AIRBUS and Nicarnica Aviation (co-founded by Dr Fred Prata). The results showed the system could work to distances of ~60 km and up to 10,000 ft but not any higher without some significant modifications. In addition, ground and satellite based imagery, radar , and lidar can be used to detect ash clouds. This information

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1836-413: A good level of removal of suspended particles. Chlorination may have to be increased to ensure adequate disinfection. Many households, and some small communities, rely on rainwater for their drinking water supplies. Roof-fed systems are highly vulnerable to contamination by ashfall, as they have a large surface area relative to the storage tank volume. In these cases, leaching of chemical contaminants from

1989-586: A great flood. Some of these ancestors used that knowledge for the good of the people, while others used it for evil and to the disadvantage of others. Raven is considered to be the protagonist hero against these evil ancestors. Tahltan social organization is founded on matriarchy and intermarriage between two main clan designations. The two main clans of Tahltan people are Tses' Kiya (pronounced Tses-kee-ya) ( Crow ) and Chiyone (pronounced Chee-oanah) (Wolf) . These two clans are further subdivided into four parties: Contemporary Tahltan society constitutes itself as

2142-503: A lack of water for hygiene, sanitation and drinking. Municipal authorities need to monitor and manage this water demand carefully, and may need to advise the public to utilise cleanup methods that do not use water (e.g., cleaning with brooms rather than hoses). Wastewater networks may sustain damage similar to water supply networks. It is very difficult to exclude ash from the sewerage system. Systems with combined storm water/sewer lines are most at risk. Ash will enter sewer lines where there

2295-901: A minor role in the determination of grain shape in phreatomagmatic eruptions. In this sort of eruption, the rising magma is quickly cooled on contact with ground or surface water. Stresses within the "quenched" magma cause fragmentation into five dominant pyroclast shape-types: (1) blocky and equant; (2) vesicular and irregular with smooth surfaces; (3) moss-like and convoluted; (4) spherical or drop-like; and (5) plate-like. The density of individual particles varies with different eruptions. The density of volcanic ash varies between 700 and 1200 kg/m for pumice, 2350–2450 kg/m for glass shards, 2700–3300 kg/m for crystals, and 2600–3200 kg/m for lithic particles. Since coarser and denser particles are deposited close to source, fine glass and pumice shards are relatively enriched in ash fall deposits at distal locations. The high density and hardness (~5 on

2448-495: A private aircraft requires a letter of authorization from the BC Parks Stikine Senior Park Ranger. Tahltan The Tahltan cultural practices and lifeways varied widely as they were often widely separated and would have to endure varying conditions depending on their locality. In Tahltan culture it was believed that some of their ancestors had knowledge that others did not from times before

2601-478: A prominent cinder cone 2,100 metres (6,900 feet) in elevation. Eve Cone , 1,740 metres (5,710 feet) in elevation, is a symmetrical cone between Buckley Lake and Mount Edziza. The northernmost cinder cone in the Desolation Lava Field is Sidas Cone which consists of two symmetrical halves and reaches an elevation of 1,540 metres (5,050 feet). Mount Edziza is drained on all sides by streams within

2754-838: A range of different pyroclasts dependent on the eruptive process. For example, ash collected from Hawaiian lava fountains consists of sideromelane (light brown basaltic glass) pyroclasts which contain microlites (small quench crystals, not to be confused with the rare mineral microlite ) and phenocrysts . Slightly more viscous eruptions of basalt (e.g., Strombolian) form a variety of pyroclasts from irregular sideromelane droplets to blocky tachylite (black to dark brown microcrystalline pyroclasts). In contrast, most high-silica ash (e.g. rhyolite) consists of pulverised products of pumice (vitric shards), individual phenocrysts (crystal fraction) and some lithic fragments ( xenoliths ). Ash generated during phreatic eruptions primarily consists of hydrothermally altered lithic and mineral fragments, commonly in

2907-566: A regional glaciation that occurred during the Early Pleistocene . The lowermost basalt flow contains basal pillows , directly overlies hyaloclastites and is brecciated and deformed, suggesting it may have been extruded onto a glacier or an ice sheet . Its extrusion onto glacial ice is also evident due to the lack of fluvial and lacustrine sediments at the base of the basalt flow which suggests it did not extrude into lakes or streams. The steep sides and unusually large thicknesses of

3060-810: A remote location that is only accessible during summer and early autumn. There is no established road access to the mountain, although the Stewart–Cassiar Highway to the east and the Telegraph Creek Road to the northwest both extend within 40 kilometres (25 miles) of Mount Edziza. Extending from these roads are horse trails that provide access to the mountain. From Telegraph Creek, the Buckley Lake Trail extends about 15 kilometres (9.3 miles) southeast along Mess Creek and Three Mile Lake. It then traverses about 15 kilometres (9.3 miles) northeast along Dagaichess Creek and Stinking Lake to

3213-549: A separate volcanic zone called the east slope centres. The Sheep Track Member is the product of an explosive eruption that originated from the southwestern flank of Ice Peak. It was deposited on all lava flows and cinder cones in the Snowshoe Lava Field with the exception of The Saucer which likely postdates the Sheep Track eruption. The source of the Sheep Track pumice is unknown but it probably originated from

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3366-417: A sequential leaching experiment on ash from the 1980 eruption of Mount St. Helens , chloride salts were found to be the most readily soluble, followed by sulfate salts Fluoride compounds are in general only sparingly soluble (e.g., CaF 2 , MgF 2 ), with the exception of fluoride salts of alkali metals and compounds such as calcium hexafluorosilicate (CaSiF 6 ). The pH of fresh ash leachates

3519-399: A series of rhyolite and trachyte domes. Basalt flows and smaller amounts of trachyte, tristanite , trachybasalt , benmoreite and mugearite produced during the second stage about 1 million years ago comprise Ice Peak , the glacially eroded remains of a stratovolcano in the form of a pyramid-shaped horn . The third and fourth stages 0.9 million years ago created basalt ridges and

3672-403: A significant health risk to those without pre-existing respiratory conditions . The health effects of volcanic ash depend on the grain size, mineralogical composition and chemical coatings on the surface of the ash particles. Additional factors related to potential respiratory symptoms are the frequency and duration of exposure, the concentration of ash in the air and the respirable ash fraction;

3825-733: A vent hidden under Tencho Glacier. Holocene in age, the Big Raven Formation has yielded dates of 6520 BCE ± 200 years, 750 BCE ± 100 years, 610 CE ± 150 years and 950 CE ± 6000 years. Underlying the aforementioned geological formations is the Tenchen Member of the Nido Formation , one of many stratigraphic units forming the Big Raven Plateau. Basalt flows and pyroclastic rocks of this Pliocene geological member are exposed north of Raspberry Pass on

3978-435: Is a 210-metre-high (690-foot) barrier of volcanic rocks on the eastern side of Mount Edziza at an elevation of 1,800 metres (5,900 feet) in the north fork of Tenchen Creek. The Neck , 1,830 metres (6,000 feet) in elevation, is a circular volcanic plug on the southeastern flank of Ice Peak. The Snowshoe Lava Field on the west flank of lce Peak contains at least 12 volcanic cones, a handful of which are named. Tennena Cone

4131-409: Is a nearly symmetrical stratovolcano, its symmetry having been broken by several steep-sided lava domes. Its eastern flank has been eroded by a narrow cirque which is bounded by near-vertical headwalls that breach the eastern summit crater rim. A system of radial meltwater channels has moderately eroded the upper flanks and summit crater rim elsewhere. Lesser modification by erosion has taken place on

4284-445: Is a symmetrical volcanic cone high on the west side of Ice Peak. It has an elevation of 2,350 metres (7,710 feet) and is almost completely surrounded by ice. Cocoa Crater is the largest cone in the Snowshoe Lava Field and is 2,117 metres (6,946 feet) in elevation. To the southeast is Coffee Crater which has an elevation of 2,000 metres (6,600 feet). Keda Cone , 1,980 metres (6,500 feet) in elevation, lies just south of Coffee Crater on

4437-438: Is also often loosely used to refer to all explosive eruption products (correctly referred to as tephra ), including particles larger than 2 mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere. The force of the gases shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash

4590-641: Is also produced when magma comes into contact with water during phreatomagmatic eruptions , causing the water to explosively flash to steam leading to shattering of magma. Once in the air, ash is transported by wind up to thousands of kilometres away. Due to its wide dispersal, ash can have a number of impacts on society, including animal and human health problems, disruption to aviation, disruption to critical infrastructure (e.g., electric power supply systems, telecommunications, water and waste-water networks, transportation), primary industries (e.g., agriculture), and damage to buildings and other structures. Volcanic ash

4743-523: Is characterized by several outlet glaciers stretching out to lower altitudes. All sides of Mount Edziza are drained by tributaries of Mess Creek and Kakiddi Creek which are situated within the Stikine River watershed . Mount Edziza consists of several types of volcanic rocks and at least six geological formations that formed during six distinct stages of volcanic activity . The first stage 1.1 million years ago produced basalt flows and

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4896-511: Is classified as a human carcinogen by the International Agency for Research on Cancer . Guideline values have been created for exposure, but with unclear rationale; UK guidelines for particulates in air (PM10) are 50 μg/m and USA guidelines for exposure to crystalline silica are 50 μg/m . It is thought that the guidelines on exposure levels could be exceeded for short periods of time without significant health effects on

5049-401: Is formed during explosive volcanic eruptions and phreatomagmatic eruptions, and may also be formed during transport in pyroclastic density currents . Explosive eruptions occur when magma decompresses as it rises, allowing dissolved volatiles (dominantly water and carbon dioxide ) to exsolve into gas bubbles. As more bubbles nucleate a foam is produced, which decreases the density of

5202-416: Is generally controlled by the mechanical properties of the wall rock broken up by spalling or explosive expansion of gases in the magma as it reaches the surface. The morphology of ash particles from phreatomagmatic eruptions is controlled by stresses within the chilled magma which result in fragmentation of the glass to form small blocky or pyramidal glass ash particles. Vesicle shape and density play only

5355-416: Is good evidence that pyroclastic flows produce high proportions of fine ash by communition and it is likely that this process also occurs inside volcanic conduits and would be most efficient when the magma fragmentation surface is well below the summit crater. Ash particles are incorporated into eruption columns as they are ejected from the vent at high velocity. The initial momentum from the eruption propels

5508-486: Is highly variable, depending on the presence of an acidic gas condensate (primarily as a consequence of the gases SO 2 , HCl and HF in the eruption plume) on the ash surface. The crystalline-solid structure of the salts act more as an insulator than a conductor . However, once the salts are dissolved into a solution by a source of moisture (e.g., fog, mist, light rain, etc.), the ash may become corrosive and electrically conductive. A recent study has shown that

5661-399: Is inflow/infiltration by stormwater through illegal connections (e.g., from roof downpipes), cross connections, around manhole covers or through holes and cracks in sewer pipes. Ash-laden sewage entering a treatment plant is likely to cause failure of mechanical prescreening equipment such as step screens or rotating screens. Ash that penetrates further into the system will settle and reduce

5814-536: 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. Misspellings of Edziza include Eddziza, Eddiza, Edidza, Edzia and Etseza. Mount Edziza rises from within

5967-509: 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

6120-504: Is partially exposed above the ice cap as a discontinuous series of spires and serrated nunataks . Spires forming the southern end of the ridge are the highest and consist of greenish grey, sparsely porphyritic trachyte . They comprise well-formed, small diameter rock columns that rise nearly vertically more than 90 metres (300 feet) above the ice cap. Nunataks elsewhere on the summit ridge are more subdued, consisting of pyroclastic debris that has been glacially reworked. The eastern side of

6273-626: Is passed between meteorological agencies, volcanic observatories and airline companies through Volcanic Ash Advisory Centers (VAAC) . There is one VAAC for each of the nine regions of the world. VAACs can issue advisories describing the current and future extent of the ash cloud. Volcanic ash not only affects in-flight operations but can affect ground-based airport operations as well. Small accumulations of ash can reduce visibility, produce slippery runways and taxiways, infiltrate communication and electrical systems, interrupt ground services, damage buildings and parked aircraft. Ash accumulation of more than

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6426-499: Is physically, socially, and economically disruptive. Volcanic ash can affect both proximal areas and areas many hundreds of kilometres from the source, and causes disruptions and losses in a wide variety of different infrastructure sectors. Impacts are dependent on: ash fall thickness; the grain size and chemistry of the ash; whether the ash is wet or dry; the duration of the ash fall; and any preparedness , management and prevention (mitigation) measures employed to reduce effects from

6579-642: Is removed from pyroclastic density currents in co-ignimbrite ash plumes. Physical and chemical characteristics of volcanic ash are primarily controlled by the style of volcanic eruption. Volcanoes display a range of eruption styles which are controlled by magma chemistry, crystal content, temperature and dissolved gases of the erupting magma and can be classified using the volcanic explosivity index (VEI) . Effusive eruptions (VEI 1) of basaltic composition produce <10 m of ejecta, whereas extremely explosive eruptions (VEI 5+) of rhyolitic and dacitic composition can inject large quantities (>10 m ) of ejecta into

6732-556: Is sparsely covered by trachyte of the Edziza Formation while the western edge of the ridge overlaps with a large flow of Edziza trachyte. Tsekone Ridge is an isolated volcanic pile adjacent to Pillow Ridge consisting of basaltic pillow lava and tuff breccia that has been cut by vertical north-trending feeder dikes . This ridge is elliptical in structure, containing a nearly 2-kilometre-long (1.2-mile), north–south trending axis. Nearly surrounding Tsekone Ridge are trachyte flows of

6885-597: Is the Pyramid Formation which formed during a period of volcanic activity 1.1 million years ago. Another period of volcanic activity about 1 million years ago deposited the Ice Peak Formation on the southern part of the Pyramid Formation. The Pillow Ridge and Edziza formations were formed by two periods of volcanic activity 0.9 million years ago, both of which overlie the Ice Peak Formation. A period of volcanic activity 0.3 million years ago deposited

7038-520: Is the only location where mugearites and benmoreites are found in the Mount Edziza volcanic complex. Felsic volcanic rocks such as trachyte and rhyolite form the central stratovolcano of Mount Edziza, the upper part of Ice Peak and several lava domes and flows, as well as pyroclastic rocks. Mount Edziza is subdivided into at least six geological formations , each the product of a distinct stage of volcanic activity. The oldest geological formation

7191-457: Is thought to supply the cations involved in the deposition of sulfate and halide salts . While some 55 ionic species have been reported in fresh ash leachates , the most abundant species usually found are the cations Na , K , Ca and Mg and the anions Cl , F and SO 4 . Molar ratios between ions present in leachates suggest that in many cases these elements are present as simple salts such as NaCl and CaSO 4 . In

7344-596: The Bulkley Valley against a project planned near Telkwa, British Columbia . In a unanimous 2003 resolution, the Union of B.C. Municipalities asked for a moratorium on coal-bed methane mining in the province. Since 2005, the Klabona Keepers, a group of Tahltan elders, have watched the road leading through Tahltan territory towards the Sacred headwaters (Klappan Valley) in opposition to development there, specifically

7497-548: The Mohs Hardness Scale ) together with a high degree of angularity, make some types of volcanic ash (particularly those with a high silica content) very abrasive. Volcanic ash consists of particles (pyroclasts) with diameters less than 2 mm (particles larger than 2 mm are classified as lapilli ), and can be as fine as 1 μm. The overall grain size distribution of ash can vary greatly with different magma compositions. Few attempts have been made to correlate

7650-499: The Stikine River watershed . Elwyn Creek is a westward-flowing stream originating from the northwestern flank of Mount Edziza. It contains one named tributary , Kadeya Creek , which flows northwest from Mount Edziza. Sezill Creek is a westward-flowing stream originating from the western flank of Mount Edziza. It is a tributary of Taweh Creek which flows northwest from just south of Mount Edziza. Elwyn Creek and Taweh Creek are tributaries of Mess Creek which flows northwestward into

7803-543: The Tahltan Nation , which comprises the membership and governments of the Tahltan First Nation and Iskut First Nation . Ten thousand years ago, the Tahltan people used obsidian from Mount Edziza to make tools and weapons for trading material. This is the main source of obsidian found in northwestern British Columbia. Coal-bed methane extraction had already been the subject of protests in

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7956-410: The eruption column . Within pyroclastic density currents particle abrasion occurs as particles violently collide, resulting in a reduction in grain size and production of fine grained ash particles. In addition, ash can be produced during secondary fragmentation of pumice fragments, due to the conservation of heat within the flow. These processes produce large quantities of very fine grained ash which

8109-422: The glacially eroded remains of an older stratovolcano whose northern flank is buried under the younger edifice of Mount Edziza. The southern and western flanks are approximal to those of the original stratovolcano whereas the eastern flank has been almost completely destroyed by headward erosion of glacial valleys. At its climax, the stratovolcano had a symmetrical profile and contained a small crater at its summit;

8262-699: The infrastructure critical to supporting modern societies, particularly in urban areas, where high population densities create high demand for services. Several recent eruptions have illustrated the vulnerability of urban areas that received only a few millimetres or centimetres of volcanic ash. This has been sufficient to cause disruption of transportation, electricity , water , sewage and storm water systems. Costs have been incurred from business disruption, replacement of damaged parts and insured losses. Ash fall impacts on critical infrastructure can also cause multiple knock-on effects, which may disrupt many different sectors and services. Volcanic ash fall

8415-476: The 1950s where gold , silver and other metals were discovered. This mineral exploration was conducted by several mineral exploration companies into the early 1990s. Mount Edziza and the surrounding area was made into a large provincial park in the early 1970s to showcase the volcanic landscape. The mountain and provincial park can only be accessed by aircraft or by a network of footpaths from surrounding roads. A number of explanations have been made regarding

8568-631: The B.C. government announced that Shell would be withdrawing its plans to explore and drill for coalbed methane gas in the Tahltan Territory. According to the Skeena Watershed Conservation Coalition , Shell has launched a lawsuit against Talhtan elders for loss of revenue. The Klabona Keepers have filed a counter-suit for failure to consult. Employment opportunities have come from natural resources development in recent years. Because of various concerns over

8721-478: The Big Raven Plateau where Eve Cone, Sidas Cone and Tsekone Ridge are visible along the route. Most of the Buckley Lake to Mowdade Lake Route is marked by a series of rock cairns from Tsekone Ridge onwards. The distance between Buckley Lake and Mowdade Lake is about 70 kilometres (43 miles) but the hiking length between these two lakes varies depending on the route taken; it can take a minimum of 7 days to hike

8874-420: The Buckley Lake to Mowdade Lake Route. The weather can change extremely fast along this hiking trail. Mount Edziza can also be accessed by float plane or helicopter, both of which are available for charter at the communities of Iskut and Dease Lake. Kakiddi Lake, Nuttlude Lake, Mowdade Lake, Mowchilla Lake and Buckley Lake are large enough to be used by float-equipped aircraft. Landing on the latter two lakes with

9027-580: The Desolation Lava Field, the Snowshoe Lava Field, Icefall Cone, Ridge Cone, Cinder Cliff and the Sheep Track Member . All of these features consist of alkali basalt and hawaiite with the exception of the Sheep Track Member which comprises a small volume of trachyte pumice. Some of the lava flows comprising the Desolation Lava Field issued from vents adjacent to the northern trim line of the summit ice cap where meltwater interacted with

9180-418: The Edziza Formation has yielded an age of 0.9 ± 0.3 million years. The Kakiddi Formation consists of the remains of thick trachyte flows and associated pyroclastic rocks. They are lithologically and geomorphologically similar to Edziza Formation trachytes but occur south of the central stratovolcano of Mount Edziza. The remains of a nearly 1-kilometre-wide (0.62-mile), rubble-covered trachyte flow are present on

9333-481: The Edziza Formation which is slightly younger than the Pillow Ridge Formation. Fission track dating of apatite from partially fused granitic xenoliths in contaminated Pillow Ridge Formation basalt has yielded ages of 0.9 ± 0.3 million years and 0.8 ± 0.25 million years. In contrast, potassium–argon dating has yielded an anomalously old age of 5.9 ± 0.9 million years which is inconsistent with

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9486-548: The Edziza Formation. From Cartoona Ridge north to Tennaya Creek are isolated remnants of Pharaoh Dome, the main mass of which comprises flow-layered rhyolite and is buried under basalt of the Ice Peak Formation. The Ice Peak Formation consists of lava and pyroclastic rocks that originated mainly from Ice Peak about 5 kilometres (3.1 miles) south of the summit of Mount Edziza. Two stratigraphic units comprise this once symmetrical stratovolcano, both of which are lithologically distinct. The lower stratigraphic unit, which forms much of

9639-452: The Hawk vein. Further geochemical and geological surveying was performed by Moongold Resources from 1987 to 1989. Mineral exploration conducted by Columbia Gold Mines from 1990 to 1992 consisted of rock sampling, trenching and 7,066 metres (23,182 feet) of drilling in 50 holes. Mount Edziza and the surrounding area was designated as a provincial park in 1972 to showcase the volcanic landscape;

9792-399: The Ice Peak Formation has yielded ages of 1.6 ± 0.2 million years, 1.5 ± 0.4 million years and 1.5 ± 0.1 million years. These dates being older than those of the Pyramid Formation may be due to excess argon in the Ice Peak Formation and are therefore considered unreliable. Ice Peak Formation basalt flows on the northwestern flank of Mount Edziza are interbedded with diamictites recording

9945-647: The Kakiddi Formation which also overlies the Ice Peak Formation. The youngest geological formation comprising Mount Edziza is the Big Raven Formation which was formed by a period of volcanic activity in the last 20,000 years. The Pyramid Formation is exposed along the deeply eroded eastern flank of Mount Edziza where rhyolite and trachyte flows, domes and pyroclastic rocks of this formation comprise ridges and prominent cliffs. A basaltic lava flow sequence up to 65 metres (213 feet) thick overlies

10098-745: The Klastline River. After entering Mount Edziza Provincial Park, the Klastline River Trail traverses northwest along the Klastline River for about 10 kilometres (6.2 miles) and then crosses the river north of the MEVC. From there, the Klastline River Trail traverses west for about 15 kilometres (9.3 miles) to the northeastern end of Buckley Lake where it meets with the Buckley Lake Trail and the Buckley Lake to Mowdade Lake Route. The Buckley Lake to Mowdade Lake Route traverses south from Buckley Lake along Buckley Creek and gradually climbs onto

10251-483: The Koosick and Ornostay bluffs, both of which are thick lobes of trachyte that originated under the summit ice cap. Both bluffs are similar in geomorphology and composition, consisting of several lava flows up to 75 metres (246 feet) thick. The Neck, which forms a prominent 215-metre-high (705-foot) buttress on Sorcery Ridge, is also part of the Ice Peak Formation. Potassium–argon dating of pantelleritic trachyte from

10404-533: The Mount Edziza volcanic complex. It has been considered by some to be the highest volcano in Canada, but other sources give higher elevations of 2,860 and 3,160 metres (9,380 and 10,370 feet) for the Silverthrone volcanic complex in southwestern British Columbia. The nearly flat summit of Mount Edziza contains a circular ridge that surrounds an ice-filled, 2-kilometre-in diameter (1.2-mile) crater . This ridge

10557-449: The SiO 2 is not attached to another element to create a new mineral. However, magmas containing less than 58% SiO 2 are thought to be unlikely to contain crystalline silica. The exposure levels to free crystalline silica in the ash are commonly used to characterise the risk of silicosis in occupational studies (for people who work in mining, construction and other industries,) because it

10710-488: The Spectrum property by Consolidated Silver Ridge Mines and Newhawk Mines between 1976 and 1981. Consolidated Silver Ridge Mines also built an airstrip and carried out 3,232 metres (10,604 feet) of drilling in 28 holes during this time period. Additional work on the Spectrum property by Newhawk Mines during this time period included the construction of an access road and 313 metres (1,027 feet) of underground development on

10863-505: The Stikine River. Tsecha Creek is a northeast-flowing stream originating from the northern flank of Mount Edziza. Nido Creek flows northeastward from the eastern side of Mount Edziza into Nuttlude Lake . Flowing from the eastern flank of Mount Edziza just southeast of The Pyramid is Tenchen Creek. Shaman Creek flows east and north into Kakiddi Lake from the southern flank of Mount Edziza. Tennaya Creek flows northeastward from

11016-563: The Stikine or Iskut rivers, potentially destroying salmon runs and threatening river bank villages. Like other volcanoes in Canada, Mount Edziza 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

11169-555: 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." The mountain was labelled Edziza Peak on Geological Survey of Canada maps as early as 1926. This name for the mountain

11322-714: 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 . Artifacts made of this obsidian have been recovered from archaeological sites over an area of more than 2,200,000 km (850,000 sq mi) across Alaska, Alberta , Yukon and the British Columbia Coast , making it the most widely distributed obsidian in western North America. The Hidden Falls archaeological site in Alaska has yielded

11475-528: The Triplex Cones, a group of three eroded circular mounds reaching an elevation of 1,785 metres (5,856 feet). Twin Cone , 1,430 metres (4,690 feet) in elevation, is a pyroclastic cone whose southeastern side has been breached. Moraine Cone has an elevation of nearly 2,135 metres (7,005 feet) and has been nearly destroyed by alpine glaciation. The northeastern side of Mount Edziza contains Williams Cone ,

11628-481: The addition of water. Volcanic ash is also produced during phreatomagmatic eruptions. During these eruptions fragmentation occurs when magma comes into contact with bodies of water (such as the sea, lakes and marshes) groundwater, snow or ice. As the magma, which is significantly hotter than the boiling point of water, comes into contact with water an insulating vapor film forms ( Leidenfrost effect ). Eventually this vapor film will collapse leading to direct coupling of

11781-411: The age of the underlying and overlying formations. This date being much older than the fission track dates most likely results from contamination and introduction of excess argon from the partially fused granitic and gneissic xenoliths in Pillow Ridge Formation basalt. The Edziza Formation consists mainly of trachyte that straddles the pantelleritic trachyte and comenditic trachyte boundary. It includes

11934-516: The ash fall. Different sectors of infrastructure and society are affected in different ways and are vulnerable to a range of impacts or consequences. These are discussed in the following sections. Ash particles of less than 10 μm diameter suspended in the air are known to be inhalable, and people exposed to ash falls have experienced respiratory discomfort, breathing difficulty, eye and skin irritation, and nose and throat symptoms. Most of these effects are short-term and are not considered to pose

12087-457: The ashfall can become a health risk and drinking of water is not recommended. Prior to an ashfall, downpipes should be disconnected so that water in the tank is protected. A further problem is that the surface coating of fresh volcanic ash can be acidic. Unlike most surface waters, rainwater generally has a very low alkalinity (acid-neutralising capacity) and thus ashfall may acidify tank waters. This may lead to problems with plumbosolvency , whereby

12240-442: The atmosphere by processes of chemical reaction, dry and wet deposition, and by adsorption onto the surface of volcanic ash. It has long been recognised that a range of sulfate and halide (primarily chloride and fluoride ) compounds are readily mobilised from fresh volcanic ash. It is considered most likely that these salts are formed as a consequence of rapid acid dissolution of ash particles within eruption plumes , which

12393-414: The atmosphere. The types of minerals present in volcanic ash are dependent on the chemistry of the magma from which it erupted. Considering that the most abundant elements found in silicate magma are silicon and oxygen , the various types of magma (and therefore ash) produced during volcanic eruptions are most commonly explained in terms of their silica content. Low energy eruptions of basalt produce

12546-494: The basal trachytic surge deposit of the Pyramid Formation; it is included as a part of this formation due to it being coeval with the early stages of Pyramid felsic volcanism. Potassium–argon dating of the Pyramid Formation has yielded ages of 1.2 ± 0.4 million years and 1.2 ± 0.03 million years from comenditic glass , as well as 0.94 ± 0.12 million years and 0.94 ± 0.05 million years from trachyte. The Pyramid Formation includes Sphinx Dome, Pharaoh Dome and The Pyramid which were

12699-689: The capacity of biological reactors as well as increasing the volume of sludge and changing its composition. The principal damage sustained by aircraft flying into a volcanic ash cloud is abrasion to forward-facing surfaces, such as the windshield and leading edges of the wings, and accumulation of ash into surface openings, including engines. Abrasion of windshields and landing lights will reduce visibility forcing pilots to rely on their instruments. However, some instruments may provide incorrect readings as sensors (e.g., pitot tubes ) can become blocked with ash. Ingestion of ash into engines causes abrasion damage to compressor fan blades. The ash erodes sharp blades in

12852-481: The central stratovolcano of Mount Edziza, as well as several satellitic features on its summit and flanks. Inside the summit crater of the stratovolcano is a succession of at least four lava lakes that are exposed in the breached eastern crater rim. They are represented by at least four cooling units, the lower two of which are about 30 metres (98 feet) thick. The two upper cooling units reach thicknesses of about 90 metres (300 feet) and may have originated from Nanook Dome,

13005-715: The central trachyte stratovolcano of Mount Edziza, respectively. Thick trachyte flows were issued during the fifth stage 0.3 million years ago, most of which have since eroded away. The sixth stage began in the last 20,000 years with the eruption of cinder cones, basalt flows and minor trachyte. Renewed volcanism could block local streams with lava flows, disrupt air traffic with volcanic ash and produce floods or lahars from melting glacial ice. Indigenous peoples have lived adjacent to Mount Edziza for thousands of years. The Tahltan people historically used volcanic glass from Mount Edziza to make tools and weaponry. Mineral exploration just southeast of Mount Edziza commenced in at least

13158-520: The cold water and hot magma. This increases the heat transfer which leads to the rapid expansion of water and fragmentation of the magma into small particles which are subsequently ejected from the volcanic vent. Fragmentation causes an increase in contact area between magma and water creating a feedback mechanism, leading to further fragmentation and production of fine ash particles. Pyroclastic density currents can also produce ash particles. These are typically produced by lava dome collapse or collapse of

13311-404: The column upwards. As air is drawn into the column, the bulk density decreases and it starts to rise buoyantly into the atmosphere. At a point where the bulk density of the column is the same as the surrounding atmosphere, the column will cease rising and start moving laterally. Lateral dispersion is controlled by prevailing winds and the ash may be deposited hundreds to thousands of kilometres from

13464-649: The column. Ash fallout is less concentrated during the final stages as the column moves downwind. This results in an ash fall deposit which generally decreases in thickness and grain size exponentially with increasing distance from the volcano. Fine ash particles may remain in the atmosphere for days to weeks and be dispersed by high-altitude winds. These particles can impact on the aviation industry (refer to impacts section) and, combined with gas particles, can affect global climate. Volcanic ash plumes can form above pyroclastic density currents. These are called co-ignimbrite plumes. As pyroclastic density currents travel away from

13617-415: The compressor, reducing its efficiency. The ash melts in the combustion chamber to form molten glass. The ash then solidifies on turbine blades, blocking air flow and causing the engine to stall. The composition of most ash is such that its melting temperature is within the operating temperature (>1000 °C) of modern large jet engines . The degree of impact depends upon the concentration of ash in

13770-444: The current peak is an erosional remnant etched from the eastern crater rim. High on the eastern rim of Ice Peak are two glaciated volcanic cones called Icefall Cone and Ridge Cone , both of which are about 2,285 metres (7,497 feet) in elevation. Punch Cone on the western flank of Ice Peak protrudes through Mount Edziza's ice cap whereas Koosick Bluff and Ornostay Bluff , also on the western flank of Ice Peak, extend westward onto

13923-425: The droplets after they leave the vent, and air friction. Shapes range from perfect spheres to a variety of twisted, elongate droplets with smooth, fluidal surfaces. The morphology of ash from eruptions of high-viscosity magmas (e.g., rhyolite, dacite, and some andesites) is mostly dependent on the shape of vesicles in the rising magma before disintegration. Vesicles are formed by the expansion of magmatic gas before

14076-595: The eastern and western flanks of Mount Edziza. Much of the Tenchen Member as well as the southern edge of the Ice Peak volcanic pile are underlain by the Armadillo Formation which consists of Miocene comendite, trachyte and alkali basalt. Most of Mount Edziza is also underlain by Miocene basalt flows of the Raspberry Formation which form the base of prominent escarpments east and west of

14229-515: The eastern flank of Ice Peak in Sorcery Valley and in the south fork of Tennaya Valley where it is divided into two tributary branches. In Kakiddi Valley, the lava flow appears to have spread out to form a once continuous, terminal lobe at least 5 kilometres (3.1 miles) wide; remnants of this terminal lobe are present in the form of isolated outcrops adjacent to Kakiddi Lake and Nuttlude Lake. The source of this Kakiddi flow remains unknown but

14382-897: The eastern side of Mount Edziza into Nuttlude Lake. All five streams are tributaries of Kakiddi Creek , a north-flowing tributary of the Klastline River which flows north into the Stikine River. Mount Edziza is part of the Northern Cordilleran Volcanic Province , 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

14535-412: The effects of an ashfall, but there will not be service interruptions. The final step of drinking water treatment is disinfection to ensure that final drinking water is free from infectious microorganisms. As suspended particles (turbidity) can provide a growth substrate for microorganisms and can protect them from disinfection treatment, it is extremely important that the water treatment process achieves

14688-595: The electrical conductivity of volcanic ash increases with (1) increasing moisture content, (2) increasing soluble salt content, and (3) increasing compaction (bulk density). The ability of volcanic ash to conduct electric current has significant implications for electric power supply systems. Volcanic ash particles erupted during magmatic eruptions are made up of various fractions of vitric (glassy, non-crystalline), crystalline or lithic (non-magmatic) particles. Ash produced during low viscosity magmatic eruptions (e.g., Hawaiian and Strombolian basaltic eruptions) produce

14841-506: The engines were started just 1–2 minutes before impact. Total damage was US$ 80 million and it took 3 months' work to repair the plane. In the 1990s, a further US$ 100 million of damage was sustained by commercial aircraft (some in the air, others on the ground) as a consequence of the 1991 eruption of Mount Pinatubo in the Philippines . In April 2010, airspace all over Europe was affected, with many flights cancelled -which

14994-484: The erupting lava to form tuff rings . These tuff rings composed of quenched breccia later transitioned into normal subaerial cinder cones as the progressing eruptions displaced ice and meltwater. The Snowshoe Lava Field contains subglacial and subaerial cones, as well as transitional cones which consist of both subaqueous and subaerial ejecta . Eruptions on the heavily eroded eastern flank of Mount Edziza created Icefall Cone, Ridge Cone and Cinder Cliff which comprise

15147-620: The eruption of Puyehue-Cordón Caulle , Chile. Volcanic ash clouds are very difficult to detect from aircraft as no onboard cockpit instruments exist to detect them. However, a new system called Airborne Volcanic Object Infrared Detector (AVOID) has recently been developed by Dr Fred Prata while working at CSIRO Australia and the Norwegian Institute for Air Research , which will allow pilots to detect ash plumes up to 60 km (37 mi) ahead and fly safely around them. The system uses two fast-sampling infrared cameras, mounted on

15300-548: The exception of fluorine . The elements iron , manganese and aluminium are commonly enriched over background levels by volcanic ashfall. These elements may impart a metallic taste to water, and may produce red, brown or black staining of whiteware, but are not considered a health risk. Volcanic ashfalls are not known to have caused problems in water supplies for toxic trace elements such as mercury (Hg) and lead (Pb) which occur at very low levels in ash leachates. Ingesting ash may be harmful to livestock , causing abrasion of

15453-414: The flanks of the mountain. Basalt at Mount Edziza is in the form of alkali basalt and hawaiite; the latter is thought to be the product of partial fractional crystallization in subterranean magma chambers . Volcanic rocks of intermediate composition such as trachybasalt , tristanite , mugearite and benmoreite are restricted to Ice Peak where they form the upper part of this subsidiary peak. Ice Peak

15606-613: The general population. There have been no documented cases of silicosis developed from exposure to volcanic ash. However, long-term studies necessary to evaluate these effects are lacking. For surface water sources such as lakes and reservoirs, the volume available for dilution of ionic species leached from ash is generally large. The most abundant components of ash leachates (Ca, Na, Mg, K, Cl, F and SO 4 ) occur naturally at significant concentrations in most surface waters and therefore are not affected greatly by inputs from volcanic ashfall, and are also of low concern in drinking water, with

15759-439: The grain size characteristics of a deposit with those of the event which produced it, though some predictions can be made. Rhyolitic magmas generally produce finer grained material compared to basaltic magmas, due to the higher viscosity and therefore explosivity. The proportions of fine ash are higher for silicic explosive eruptions, probably because vesicle size in the pre-eruptive magma is smaller than those in mafic magmas. There

15912-558: The headwaters and, in June 2007, 14 different environmental groups sent a joint letter to Shell opposing the project. Representatives from Shell assert a determination to reach consensus in the community and note that the elected Tahltan Central Council (TCC) agreed to the exploration. Chief Jerry Asp was forced to resign in 2005 after protests from Tahltan members accusing him of a conflict of interest because of his involvement with two pro-development organizations. On December 18, 2012,

16065-697: The headwaters, but in 2005 four Shell employees who arrived at the band office in Iskut were turned away by a group of elders and no drilling occurred that summer. Non-violent blockades in 2005 and 2006 delayed development efforts and led to the arrests of 13 protesters. Talhtan territory was the site of half of all the mining exploration in British Columbia during 2006. Protests in Smithers have been as large as 600 people. David Suzuki and Wade Davis have both criticized plans for coal-bed methane mining in

16218-503: The highest point of the Mount Edziza volcanic complex . However, it had an elevation of at least 3,396 metres (11,142 feet) before its formerly cone-shaped summit was likely destroyed by a violent eruption in the geologic past; its current flat summit contains an ice-filled, 2-kilometre-in diameter (1.2-mile) crater . The mountain contains several lava domes , cinder cones and lava fields on its flanks, as well as an ice cap that

16371-408: The ice cap near the head of Tennaya Creek . At the head of Tenchen Creek is Tenchen Glacier , a debris-covered glacier on the eastern side of the ice cap. Tencho Glacier at the southern end of the ice cap is the largest outlet glacier. At the head of Tennaya Creek on the eastern side of the ice cap is Tennaya Glacier . As a part of the Mount Edziza volcanic complex, Mount Edziza was covered by

16524-708: The lands, the parties involved balance development and environmental aspects. Talk of an Alaska-Canada railroad traversing Tahltan lands recurs every so often with feasibility studies being done. Tahltan is a poorly documented Northern Athabaskan language . Some linguists consider Tahltan to be a language with three divergent but mutually intelligible dialects. Other linguists consider these to be separate languages. The number of speakers are below. Volcanic ash Volcanic ash consists of fragments of rock, mineral crystals , and volcanic glass , produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash

16677-420: The largest of three lava domes consisting of Edziza Formation trachyte. Nanook Dome is about 750 metres (2,460 feet) in diameter whose structure appears to be nearly identical to its original form. The other two Edziza Formation trachyte domes, Glacier Dome and Triangle Dome, are elliptical in structure and contain concentric flow layering. Potassium–argon dating of pantelleritic trachyte or comenditic trachyte from

16830-513: The magma has solidified. Ash particles can have varying degrees of vesicularity and vesicular particles can have extremely high surface area to volume ratios. Concavities, troughs, and tubes observed on grain surfaces are the result of broken vesicle walls. Vitric ash particles from high-viscosity magma eruptions are typically angular, vesicular pumiceous fragments or thin vesicle-wall fragments while lithic fragments in volcanic ash are typically equant, or angular to subrounded. Lithic morphology in ash

16983-407: The magma, accelerating it up the conduit. Fragmentation occurs when bubbles occupy ~70–80 vol% of the erupting mixture. When fragmentation occurs, violently expanding bubbles tear the magma apart into fragments which are ejected into the atmosphere where they solidify into ash particles. Fragmentation is a very efficient process of ash formation and is capable of generating very fine ash even without

17136-501: 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. Mount Edziza lies within the traditional territory of the Tahltan people which covers an area of more than 93,500 square kilometres (36,100 square miles). Historically, Mount Edziza and other volcanoes of the Mount Edziza volcanic complex were sources of obsidian for

17289-400: The main sources of the rhyolites and trachytes of this geological formation. The Pyramid is a prominent trachyte dome whose structure has not been greatly modified by erosion, nor has it been buried under younger lavas. In contrast, much of the southern edge of Sphinx Dome has been destroyed by headward erosion of Cook Creek; the western half of this rhyolite dome is also buried under trachyte of

17442-438: The middle of the Big Raven Plateau, a barren plateau in Cassiar Land District bounded on the west by Mess Valley, on the north by Klastline Valley , on the east by Kakiddi Valley and on the south by Chakima and Walkout valleys, the latter two of which are separated by mountainous terrain . It lies at the northern end of the Mount Edziza volcanic complex which also includes the smaller Arctic Lake and Kitsu plateaus to

17595-450: 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 from the volcano. 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. Mount Edziza lies under a major air route from Vancouver , British Columbia to Whitehorse , Yukon, suggesting

17748-400: The mountain is characterized by a series of ridges with intervening valleys. Among these ridges are Idiji Ridge and Sorcery Ridge which are the namesakes of Idiji Glacier and Sorcery Creek , respectively. About 5 kilometres (3.1 miles) south of the summit is Ice Peak , the south peak of Mount Edziza. This prominent pyramid-shaped horn has an elevation of 2,500 metres (8,200 feet) and is

17901-450: The mountain. Edzerza was buried on Mount Edziza but his surname was erroneously spelled "Edzertza" on his grave marker. Williams Cone on the northeastern side of Mount Edziza was named in honour of Hank Williams. Eve Cone between Mount Edziza and Buckley Lake was named in honour of Johnny Edzerza's wife, Eve Brown Edzerza. Mount Edziza continues to be an important cultural resource for the Tahltan people. In 2021, Chad Norman Day, president of

18054-425: The mountain. It may sense an increase in seismic activity if Mount Edziza becomes highly restless, but this may only provide a warning for a large eruption; the system might detect activity only once the volcano has started erupting. If Mount Edziza 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

18207-845: The mountain. These geological formations are underlain by 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 . Natural Resources Canada considers Mount Edziza a high threat volcano because it has had the highest eruption rate in Canada throughout the Holocene. However, its extremely remote location makes it less hazardous than Mount Garibaldi , Mount Price , Mount Cayley and Mount Meager in southwestern British Columbia. Mount Edziza trachyte and rhyolite have silica -rich compositions that are comparable to those associated with

18360-415: The neoglacial period in the 19th century which has resulted in rapid glacial recession throughout the Mount Edziza volcanic complex. 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. Mount Edziza has an elevation of 2,786 metres (9,140 feet), making it the highest point of

18513-525: The northeastern end of Buckley Lake where it meets with the Klastline River Trail and the Buckley Lake to Mowdade Lake Route. To the east, the roughly 50-kilometre-long (31-mile) Klastline River Trail begins at the community of Iskut on the Stewart–Cassiar Highway. It extends northwest and west along the Klastline River for much its length. The trail enters Mount Edziza Provincial Park at about 25 kilometres (16 miles) where Kakiddi Creek drains into

18666-415: The northwest and 85 kilometres (53 miles) to the northeast, respectively. Mount Edziza is covered with snow year-round, containing a 15-kilometre-long (9.3-mile) and 9-kilometre-wide (5.6-mile) ice cap which covers an area of 70 square kilometres (27 square miles). Several small outlet glaciers extending down to altitudes of 1,700 to 2,000 metres (5,600 to 6,600 feet) drain the ice cap; outlet glaciers on

18819-540: 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"

18972-436: The plume, the length of time the aircraft spends within the plume and the actions taken by the pilots. Critically, melting of ash, particularly volcanic glass, can result in accumulation of resolidified ash on turbine nozzle guide vanes, resulting in compressor stall and complete loss of engine thrust. The standard procedure of the engine control system when it detects a possible stall is to increase power which would exacerbate

19125-647: The power delivery process: Groundwater-fed systems are resilient to impacts from ashfall, although airborne ash can interfere with the operation of well-head pumps. Electricity outages caused by ashfall can also disrupt electrically powered pumps if there is no backup generation. The physical impacts of ashfall can affect the operation of water treatment plants. Ash can block intake structures, cause severe abrasion damage to pump impellers and overload pump motors. Ash can enter filtration systems such as open sand filters both by direct fallout and via intake waters. In most cases, increased maintenance will be required to manage

19278-443: The problem. It is recommended that pilots reduce engine power and quickly exit the cloud by performing a descending 180° turn. Volcanic gases, which are present within ash clouds, can also cause damage to engines and acrylic windshields, and can persist in the stratosphere as an almost invisible aerosol for prolonged periods of time. There are many instances of damage to jet aircraft as a result of an ash encounter. On 24 June 1982,

19431-419: The progressive encroachment of urban development into higher risk areas, closer to volcanic centres, increasing the human exposure to volcanic ash fall events. Direct health effects of volcanic ash on humans are usually short-term and mild for persons in normal health, though prolonged exposure potentially poses some risk of silicosis in unprotected workers. Of greater concern is the impact of volcanic ash on

19584-622: The property included copper , gold , lead , silver and zinc . Mineral exploration on the Spectrum property began in at least 1957 when Torbit Silver Mines performed surface work on the gold-bearing Hawk vein . This was followed by drilling of the Hawk vein by Shawnigan Mining and Smelting in 1967. Exploration by Mitsui Mining and Smelting in 1970 involved geophysical and geochemical surveying. From 1971 to 1973, Imperial Oil conducted geophysical, geological and geochemical surveying, as well as 463 metres (1,519 feet) of drilling in four holes. Geochemical and geological surveys were conducted on

19737-423: The proportion of ash with less than 10 μm diameter, known as PM 10 . The social context may also be important. Chronic health effects from volcanic ash fall are possible, as exposure to free crystalline silica is known to cause silicosis . Minerals associated with this include quartz , cristobalite and tridymite , which may all be present in volcanic ash. These minerals are described as ‘free’ silica as

19890-581: The quality of the fibre. As the usual pastures and plants become covered in volcanic ash during eruption some livestock may resort to eat whatever is available including toxic plants. There are reports of goats and sheep in Chile and Argentina having natural abortions in connection to volcanic eruptions. Volcanic ash can disrupt electric power supply systems at all levels of power generation, transformation, transmission, and distribution. There are four main impacts arising from ash-contamination of apparatus used in

20043-523: The recreation area lied east of Mount Edziza until 2003 when it was disestablished. Mount Edziza Provincial Park now covers an area of 266,180 hectares (657,700 acres), making it one of the largest provincial parks in British Columbia. In 2021, an approximately 3,528-hectare (8,720-acre) conservation area called the Mount Edziza Conservancy was established east of Mount Edziza along the eastern border of Mount Edziza Provincial Park. It

20196-459: The ridge has been breached by active cirques where remnants of several lava lakes are exposed inside the crater. Formation of the summit crater was likely caused by a violent eruption at the zenith of the mountain's growth. Prior to its formation, the summit of the mountain was at least 610 metres (2,000 feet) higher than it is today, having possibly risen as a narrower summit cone. The central, 2,786-metre-high (9,140-foot) edifice of Mount Edziza

20349-553: The south side of upper Taweh Creek . A saucer -shaped mound of lava called The Saucer is 1,920 metres (6,300 feet) in elevation and has a diameter of about 0.5 square kilometres (0.19 square miles). The Desolation Lava Field contains at least 10 cinder cones, most of which are clustered near the northern trim line of Mount Edziza's ice cap. Sleet Cone and Storm Cone are rounded, mostly soil-covered, conical mounds that reach elevations of 1,783 metres (5,850 feet) and 2,135 metres (7,005 feet), respectively. North of Storm Cone are

20502-544: The south. This complex of shield volcanoes , stratovolcanoes , lava domes , calderas and cinder cones forms a broad, intermontane plateau at the eastern edge of the Tahltan Highland , a southeast-trending upland area extending along the western side of the Stikine Plateau . Mount Edziza is in the Southern Boreal Plateau Ecosection which consists of several upland summits as well as wide river valleys and deeply incised plateaus. It

20655-448: The southeastern crater rim of Mount Edziza called Nanook Dome has an elevation of 2,710 metres (8,890 feet). Sphinx Dome , 2,380 metres (7,810 feet) in elevation, is a partially buried lava dome on the northeastern flank of Mount Edziza. Remnants of a volcanic pile called Pharaoh Dome occur along the eastern flank of Mount Edziza. They lie at an elevation of 2,200 metres (7,200 feet) between Tennaya Creek and Cartoona Ridge. Cinder Cliff

20808-399: The southern and northwestern flanks of the stratovolcano. Along the north side of Tenchen Valley on the eastern flank of the stratovolcano are 850-metre-high (2,790-foot) cliffs exposing explosion breccias , trachyte lavas and landslide or lahar deposits. Although Mount Edziza is surrounded by relatively flat terrain of the Big Raven Plateau to the north, west and south, the terrain east of

20961-616: The surrounding Big Raven Plateau. The northeastern side of Mount Edziza contains The Pyramid , a pyramid-shaped lava dome 2,199 metres (7,215 feet) in elevation. Pillow Ridge on the northern side of Mount Edziza has an elevation of 2,400 metres (7,900 feet) while Tsekone Ridge northwest of Mount Edziza has an elevation of 1,920 metres (6,300 feet). High on the western side of Mount Edziza is Triangle Dome , an elliptical lava dome 2,680 metres (8,790 feet) in elevation. Glacier Dome reaches an elevation of 2,225 metres (7,300 feet) on Mount Edziza's lower northeastern flank. A circular lava dome on

21114-580: The teeth, and hypersensibility to pressure in the legs and back. Ash ingestion may also cause gastrointestinal blockages. Sheep that ingested ash from the 1991 Mount Hudson volcanic eruption in Chile, suffered from diarrhoea and weakness. Ash accumulating in the back wool of sheep may add significant weight, leading to fatigue and sheep that can not stand up. Rainfall may result in a significant burden as it adds weight to ash. Pieces of wool may fall away and any remaining wool on sheep may be worthless as poor nutrition associated with volcanic eruptions impacts

21267-748: The teeth, and in cases of high fluorine content, fluorine poisoning (toxic at levels of >100 μg/g) for grazing animals. It is known from the 1783 eruption of Laki in Iceland that fluorine poisoning occurred in humans and livestock as a result of the chemistry of the ash and gas, which contained high levels of hydrogen fluoride . Following the 1995/96 Mount Ruapehu eruptions in New Zealand, two thousand ewes and lambs died after being affected by fluorosis while grazing on land with only 1–3 mm of ash fall. Symptoms of fluorosis among cattle exposed to ash include brown-yellow to green-black mottles in

21420-452: The trachyte flows comprising Koosick and Ornostay bluffs is attributed to them having been extruded through glacial ice. The Pillow Ridge Formation is restricted to Pillow Ridge and Tsekone Ridge on Mount Edziza's northwestern flank, both of which are glaciovolcanic in origin. Pillow Ridge is a nearly 4-kilometre-long (2.5-mile), northwesterly-trending ridge of basaltic pillow lava, pillow breccia, tuff breccia and dikes . Its upper surface

21573-612: The tributary branch that descended Tennaya Valley probably originated from a vent near the summit of Ice Peak that is now covered by glaciers. Another plausible source is Nanook Dome on the southeastern crater rim of Mount Edziza. A relatively small trachyte flow descended from a vent on the western flank of Ice Peak and spread onto the Big Raven Plateau. Potassium–argon dating of the Kakiddi Formation has yielded ages of 0.31 ± 0.07 million years from mugearite, as well as 0.30 ± 0.02 million years, 0.29 ± 0.02 million years and 0.28 ± 0.02 million years from trachyte. The Big Raven Formation includes

21726-541: The upper slopes but barren rock is abundant at higher elevations. The region is characterized by warm summers and cold, snowy winters; 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 a possibility at any time of the year. The closest weather stations to Mount Edziza are located at Telegraph Creek and Dease Lake , which lie about 40 kilometres (25 miles) to

21879-498: The valley is used for fishing, hunting, and trapping. It is the site of a Tahltan burial ground and a cultural camp where Talhtan youth can learn their culture in the summer. In 2004, Shell was awarded the oil and gas rights to the Klappan Valley, one of British Columbia 's largest coal deposits with an estimated 230 km (8 trillion cu ft) of methane . That year, Shell drilled three exploratory wells at

22032-477: The volcanic pile, is an assemblage of mostly thin basalt flows. Lavas of intermediate composition such as tristanite, trachybasalt and mugearite are very limited in extent. The upper stratigraphic unit is a highly varied succession of lavas and pyroclastic rocks forming the high, central edifice of Ice Peak. It consists of basalt, trachyte and a variety of intermediate rocks such as tristanite, trachybasalt, benmoreite and mugearite. The Ice Peak Formation also includes

22185-451: The volcano 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 a potential hazard as they have formerly dammed local streams. Another potential hazard at Mount Edziza is the ignition of wildfires by eruptions as the surrounding area has vegetation. An eruption under the ice cap could produce floods or lahars that may flow into

22338-409: The volcano, depending on eruption column height, particle size of the ash and climatic conditions (especially wind direction and strength and humidity). Ash fallout occurs immediately after the eruption and is controlled by particle density. Initially, coarse particles fall out close to source. This is followed by fallout of accretionary lapilli , which is the result of particle agglomeration within

22491-413: The volcano, smaller particles are removed from the flow by elutriation and form a less dense zone overlying the main flow. This zone then entrains the surrounding air and a buoyant co-ignimbrite plume is formed. These plumes tend to have higher concentrations of fine ash particles compared to magmatic eruption plumes due to the abrasion within the pyroclastic density current. Population growth has caused

22644-423: The water is more aggressive towards materials that it comes into contact with. This can be a particular problem if there are lead-head nails or lead flashing used on the roof, and for copper pipes and other metallic plumbing fittings. During ashfall events, large demands are commonly placed on water resources for cleanup and shortages can result. Shortages compromise key services such as firefighting and can lead to

22797-466: The western side of the ice cap spread in broad lobes onto the Big Raven Plateau while distributary glaciers on the eastern side drape down steep slopes to form discontinuous icefalls . The Mount Edziza ice cap is the only one worthy of note on the Stikine Plateau. Four glaciers of the ice cap are named, all of which have names of Tahltan origin. Idiji Glacier descends from the eastern side of

22950-606: Was adopted by the Geographical Names Board of Canada on September 24, 1945, as identified on the 1926 Geological Survey of Canada map sheet 309A. The name Edziza Mountain appeared in the 1930 BC Gazetteer in which it was erroneously spelled Edzia. On December 3, 1974, the form of name was changed from Edziza Peak to Mount Edziza in accordance to a 1927 British Columbia Land Surveyors report, two world aeronautical charts published in 1950 and three British Columbia maps published in 1931, 1933 and 1943. The form of name

23103-545: Was also changed to reflect entrenched local usage and in conformation with Mount Edziza Provincial Park which was established in 1972. Ice Peak was officially named on January 2, 1980, to retain Mount Edziza's Tahltan name, Ice Mountain, which translates to Tenh Dẕetle in the Tahltan language. Just southeast of Mount Edziza was the Spectrum or Red Dog property, a block of mineral claims that covered quartz , pyrite and chalcopyrite mineralization in fractured sedimentary and volcanic rocks of Late Triassic age. Commodities on

23256-544: Was established in collaboration with Skeena Resources, BC Parks , the Tahltan Central Government and the Nature Conservancy of Canada after Skeena Resources returned their mineral tenures on the Spectrum property. The name of this conservation area was changed to the Tenh Dẕetle Conservancy in 2022 to better reflect the culture, history and tradition of the Tahltan First Nation . Mount Edziza lies in

23409-563: Was unprecedented-due to the presence of volcanic ash in the upper atmosphere from the eruption of the Icelandic volcano Eyjafjallajökull . On 15 April 2010, the Finnish Air Force halted training flights when damage was found from volcanic dust ingestion by the engines of one of its Boeing F-18 Hornet fighters. In June 2011, there were similar closures of airspace in Chile, Argentina, Brazil, Australia and New Zealand, following

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