{{short description|Volcanic activity in Canada}} [[File:Mount Edziza, British Columbia.jpg|thumb|right|Mount Edziza, a stratovolcano in northwestern British Columbia]] thumb|right|A topographic map of Canada, showing elevations shaded from green (lower) to brown (higher)
Volcanic activity is a major part of the geology of Canada and is characterized by many types of volcanic landform, including lava flows, volcanic plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes, calderas, diatremes, and maars, along with less common volcanic forms such as tuyas and subglacial mounds.
Though Canada's volcanic history dates back to the Precambrian eon, at least 3.11 billion years ago, when its part of the North American continent began to form,<ref name="API">{{cite web|title=Large Igneous Provinces in Canada Through Time and Their Metallogogenic Potential Appendix 2 |work=Mineral Deposits of Canada |publisher=Geological Survey of Canada |date=September 24, 2008 |url=http://gsc.nrcan.gc.ca/mindep/synth_prov/lip/tables/appendix2_e.php |access-date=January 21, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110604175843/http://gsc.nrcan.gc.ca/mindep/synth_prov/lip/tables/appendix2_e.php |archive-date=June 4, 2011 }}</ref> volcanism continues to occur in Western and Northern Canada in modern times, where it forms part of an encircling chain of volcanoes and frequent earthquakes around the Pacific Ocean called the Pacific Ring of Fire.<ref name="HEPO"/> Because volcanoes in Western and Northern Canada are in relatively remote and sparsely populated areas and their activity is less frequent than with other volcanoes around the Pacific Ocean, Canada is commonly thought to occupy a gap in the Ring of Fire between the volcanoes of the western United States to the south and the Aleutian volcanoes of Alaska to the north.<ref name="SLV"/> Even so, the mountainous landscapes of the Canadian provinces of Alberta, British Columbia, Yukon, and the Northwest Territories include more than 100 volcanoes that have been active during the past two million years and whose eruptions have claimed many lives.<ref name="SLV"/>
Volcanic activity is responsible for many of Canada's geological and geographical features and mineralization, including the nucleus of the North American continent, known as the Canadian Shield. Volcanism has led to the formation of hundreds of volcanic areas and extensive lava formations across Canada. The country's different volcano and lava types originate from different tectonic settings and types of volcanic eruptions, ranging from passive lava eruptions to violent explosive eruptions. Canada has a rich record of very large volumes of magmatic rock called large igneous provinces, represented by deep-level plumbing systems consisting of giant dike swarms, sill provinces and layered intrusions.<ref name="GHE"/> The most capable large igneous provinces in Canada are Archean greenstone belts estimated at 3.8 to 2.5 billion years old, containing a rare volcanic rock called komatiite.<ref name="GHE"/>
== Eruption styles and volcano formations == {| class="wikitable mw-collapsible" |+ '''Eruption types and examples''' |- ! Hawaiian eruptions | thumb|right|Hawaiian eruption: 1: ash plume, 2: lava fountain, 3: crater, 4: lava lake, 5: fumaroles, 6: lava flow, 7: layers of lava and ash, 8: stratum, 9: sill, 10: magma conduit, 11: magma chamber, 12: dike || {{Main|Hawaiian eruption}} Hawaiian eruptions are passive eruptions characterized by effusive emission of highly fluid basalt lavas with low gas contents. Like other Hawaiian eruptions, the relative volume of ejected pyroclastic material is less than that of all other eruption types. The main phenomenons during Hawaiian eruptions is steady lava fountaining and the production of thin lava flows that eventually build up into large, broad shield volcanoes. Eruptions are also common in central vents near the summit of shield volcanoes, and along linear volcanic vents radiating outward from the summit area. Lava advances downslope away from their source vents in lava channels and lava tubes.
[[File:Eve Cone.jpg|thumb|left|Eve Cone, one of the best preserved cinder cones in Canada.]] In Canada, cinder cones form when lava fountains release fragments of lava that harden in the air and fall around a linear volcanic vent. The rock fragments, often known as cinder or scoria, are glassy and contain gas bubbles "frozen" into place as magma exploded into the air and then cooled quickly. Some of the lava is not fragmented and flows from the vent as a lava flow.<ref>{{cite web|title=Types of volcanoes |work=Volcanoes of Canada |publisher=Geological Survey of Canada |date=February 17, 2009 |url=http://gsc.nrcan.gc.ca/volcanoes/type_e.php |access-date=February 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090202064852/http://gsc.nrcan.gc.ca/volcanoes/type_e.php |archive-date=February 2, 2009 }}</ref> Cinder cones are also called pyroclastic cones and are found in volcanic fields, on the flanks of shield volcanoes, stratovolcanoes and calderas.<ref>{{cite gvp|vn=320160|vtab=Subfeatures|title=Silverthrone|access-date=March 2, 2009}}</ref><ref>{{cite gvp|vn=320200|vtab=Subfeatures|title=Garibaldi|access-date=March 2, 2009}}</ref><ref>{{cite gvp|vn=320070|vtab=Subfeatures|title=Spectrum Range|access-date=March 2, 2009}}</ref><ref>{{cite gvp|vn=320030|vtab=Subfeatures|title=Atlin Volcanic Field|access-date=March 2, 2009}}</ref> For example, geologists have identified at least 30 young cinder cones on the Mount Edziza volcanic complex, a large shield volcano in northwestern British Columbia with an area of {{convert|1000|km2}}.<ref name="SLV"/> Eve Cone, on the northern end of the Mount Edziza volcanic complex, is one of the best preserved cinder cones in Canada, due to its undeformed and symmetrical shape.<ref name="ACO">{{cite web|title=Stikine volcanic belt: Mount Edziza|work=Catalogue of Canadian volcanoes|publisher=Geological Survey of Canada|date=February 13, 2008|url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_edziza_e.php|access-date=December 20, 2008|url-status=dead|archive-url=https://web.archive.org/web/20080610154204/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_edziza_e.php|archive-date=June 10, 2008}}</ref>
During other Hawaiian eruptions, fluid basaltic lava may pond in vents, craters, or broad depressions to produce lava lakes. As lava lakes solidify, they create a grey-silver crust that is usually only a few centimeters thick. Active lava lakes comprise young crust that is repeatedly destroyed and regenerated. Convective motion of the underlying lava causes the crust to break into slabs and sink. This then exposes new lava at the surface that cools into a new crustal layer which will again fracture into slabs and be recycled into the circulating lava beneath the crust. |- ! Phreatic and phreatomagmatic eruptions | thumb|right|Phreatic eruption: 1: water vapor cloud, 2: magma conduit, 3: layers of lava and ash, 4: stratum, 5: water table, 6: explosion, 7: magma chamber || {{Main|Phreatic eruption|Phreatomagmatic eruption}} Phreatic eruptions occur when rising magma makes contact with ground or surface water.<ref name="ZZKL">{{cite web|publisher=USGS|url=https://volcanoes.usgs.gov/images/pglossary/HydroVolcEruption.php|title=VHP Photo Glossary: Phreatic eruption|date=July 17, 2008|access-date=February 24, 2009}}</ref> The extreme temperature of the magma causes near-instantaneous evaporation, resulting in an explosion of steam, water, ash, rocks and volcanic bombs.<ref name="ZZKL"/> The temperature of the rock fragments can range from cold to incandescent. If magma is included, the term phreatomagmatic may be used. Phreatomagmatic eruptions occasionally create broad, low-relief volcanic craters called maars.<ref name="AAAJ"/> These explosion craters are interpreted to have formed above rubble-filled volcanic pipes called diatremes; deep erosion of a maar presumably would expose a diatreme.<ref name="AMC maar">{{cite web|publisher=USGS|url=https://vulcan.wr.usgs.gov/Glossary/Maars/description_maars.html|title=Maars and Tuff Cones|date=August 28, 2006|access-date=February 26, 2009}}</ref> Maars range in size from {{convert|61|to(-)|1981|m}} across and from {{convert|9|to(-)|198|m|ft}} deep and are commonly filled with water to form a crater lake.<ref name="AMC maar"/> Fiftytwo Ridge at the southeastern end of Wells Gray Provincial Park in southeastern British Columbia is an example of a volcano containing lake-filled maars.<ref>{{cite web|publisher=Government of British Columbia |url=https://apps.gov.bc.ca/pub/bcgnws/names/37835.html |archive-url=https://archive.today/20070815193807/http://ilmbwww.gov.bc.ca/bcgn-bin/bcg10?name=37835 |url-status=live |archive-date=August 15, 2007 |title=BCGNIS Query Results |access-date=February 25, 2009 }}</ref> Most maars have low rims composed of a mixture of loose fragments of volcanic rocks and rocks torn from the walls of the diatreme.<ref name="AMC maar"/> Phreatic explosions can be accompanied by carbon dioxide or hydrogen sulfide gas emissions.<ref name="ANNK">{{cite journal |last1=Guern |first1=F. |last2=Tazieff |first2=H. |last3=Pierret |first3=R. Faivre |title=An example of health hazard: People killed by gas during a phreatic eruption: Diëng plateau (Java, Indonesia), February 20th 1979 |journal=Bulletin Volcanologique |date=June 1982 |volume=45 |issue=2 |pages=153–156 |doi=10.1007/BF02600430 |bibcode=1982BVol...45..153L |s2cid=140614036 }}</ref> |- ! Subglacial eruptions | thumb|right|Subglacial eruption: 1: water vapor cloud, 2: lake, 3: ice, 4: layers of lava and ash, 5: strata, 6: pillow lava, 7: magma conduit, 8: magma chamber, 9: dike || {{Main|Subglacial eruption}} Subglacial eruptions occur when lava erupts under large portions of glacial ice. As lava erupts under a large glacier, the heat of the lava would immediately start to melt the overlying glacial ice to produce meltwater.<ref name="AAAJ"/> The resulting meltwater would quickly harden the lava to produce pillow-shaped masses called pillow lava.<ref name="AAAJ"/> In places, the pillow lava will fracture to create other types of volcanic deposits called pillow breccia, tuff breccia, and hyaloclastite.<ref name="AAAJ"/> If magma intruded and melted a vertical pipe through the overlying glacier, the partially molten mass would cool as a large block with gravity flattening its upper surface to form a flat-topped, steep-sided subglacial volcano called a tuya.<ref name="AAAJ"/> The term tuya originates from Tuya Butte in far northern British Columbia.<ref name="AAAJ"/> While still in graduate school in 1947, Canadian geologist William Henry Mathews coined the term "tuya" to refer to these distinctive volcanic formations and was one of the first people on Earth to describe in detail these types of subglacial volcanoes.<ref name="AAAJ"/> Tuya Butte is the first such landform analyzed in the geological literature, and its name has since become standard worldwide among volcanologists in referring to and writing about tuyas.<ref name="AAAJ">{{cite web|title=Types of volcanoes |work=Volcanoes of Canada |publisher=Geological Survey of Canada |date=February 17, 2009 |url=http://gsc.nrcan.gc.ca/volcanoes/type_e.php |access-date=December 15, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20090202064852/http://gsc.nrcan.gc.ca/volcanoes/type_e.php |archive-date=February 2, 2009 }}</ref><ref>{{cite web|publisher=Geological Survey of Canada |url=http://www.cgu-ugc.ca/cnc-iugg/IAVCEI99.htm |title=Volcanism in Canada |access-date=December 15, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20090715112718/http://www.cgu-ugc.ca/cnc-iugg/IAVCEI99.htm |archive-date=July 15, 2009 }}</ref> Other subglacial volcanoes, including subglacial mounds, are formed when the erupted magma is not hot enough to melt through the overlying glacial ice.<ref name="AAAJ"/> Once the glaciers melt away, the tuyas and subglacial mounds would reappear with a distinctive shape as a result of their confinement within glacial ice.<ref name="AAAJ"/>
<!--thumb|left|Tuya Butte in northern British Columbia--> Because volcanic activity in Western and Northern Canada was contemporaneous with the ebb and flow of past glaciations, other volcanoes display ice-contact features. Mount Garibaldi in southwestern British Columbia is the only major volcano in North America known to have formed upon a regional ice sheet during the last glacial period, which began 110,000 years ago and ended between 10,000 and 15,000 years ago.<ref>{{cite book|last=Armitage|first=Doreen|title=Around the Sound: A History of Howe Sound-Whistler|publisher=Harbour Publishing|year=2001|url=http://www.harbourpublishing.com/excerpt/AroundtheSound/103|isbn=978-1-55017-235-5|oclc=56329598|access-date=February 19, 2008|archive-date=July 10, 2020|archive-url=https://web.archive.org/web/20200710151855/http://www.harbourpublishing.com/excerpt/AroundtheSound/103|url-status=dead}}</ref> Hoodoo Mountain in northern British Columbia was contained within basins thawed in the ice and assumed the flat-topped, steep-sided form of a tuya.<ref>{{cite web|title=The Hoodoo Mountain project |work=Volcanoes of Canada |publisher=Geological Survey of Canada |date=February 12, 2008 |url=http://cgc.rncan.gc.ca/volcanoes/hoodoo_e.php |access-date=February 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20061018030102/http://cgc.rncan.gc.ca/volcanoes/hoodoo_e.php |archive-date=October 18, 2006 }}</ref> Pyramid Mountain, in the Shuswap Highland of east-central British Columbia, was formed under more than {{convert|1000|m}} of glacial ice to assume the form of a subglacial mound.<ref>{{cite web|title=Wells Gray - Clearwater volcano field |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=February 13, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/belt_wells_e.php |access-date=February 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20061008193700/http://gsc.nrcan.gc.ca/volcanoes/cat/belt_wells_e.php |archive-date=October 8, 2006 }}</ref> The Fort Selkirk Volcanic Field in central Yukon contains volcanic features that were erupted subglacially when the large Cordilleran Ice Sheet existed in this area between 0.8 and one million years ago.<ref name="QQJ">{{cite gvp|vn=320010| title=Fort Selkirk|access-date=March 2, 2009}}</ref> |- ! Submarine eruptions | thumb|right|Submarine eruption: 1: water vapor cloud, 2: water, 3: stratum, 4: lava flow, 5: magma conduit, 6: magma chamber, 7: dike, 8: pillow lava || {{Main|Submarine eruption}} Submarine eruptions are eruptions that occur underwater.<ref name="OQ">{{cite web|publisher=Smithsonian Institution Global Volcanism Program |url=http://www.volcano.si.edu/world/tpgallery.cfm?category=Submarine%20Eruptions |title=Types and Processes Gallery - Submarine Eruptions |access-date=April 27, 2008 |archive-url=https://web.archive.org/web/20080417040244/http://www.volcano.si.edu/world/tpgallery.cfm?category=Submarine%20Eruptions |archive-date=April 17, 2008 |url-status=dead }}</ref> The appearance of these eruptions is different from those that occur on land.<ref name="OQ"/> When lava erupts it will be quickly cooled by the unlimited supply of water surrounding a submarine volcano, creating pillow lava.<ref name="OQ"/> Explosive fragmentation of lavas forms hyaloclastites.<ref name="OQ"/> Deep-sea submarine eruptions usually occur where the ocean floor is being pulled apart by plate tectonic movements called mid-ocean ridges, where about 75% of the Earth's magmatic eruptions occur.<ref name="OQ"/> Shallow submarine eruptions can cause explosions of steam and volcanic ash called Surtseyan eruptions, named for the island of Surtsey off the southern coast of Iceland.<ref name="OQ"/> Explosive submarine eruptions usually eject large quantities of very light volcanic rock called pumice.<ref name="OQ"/> This very light volcanic rock can initially float on water, forming long-lived rafts of floating pumice carried long distances from the volcano by ocean currents.<ref name="OQ"/> Lava flows entering water can cause explosions that form piles of ash and rubble similar to cinder cones, although they were formed from rootless vents not located above a magma conduit.<ref name="OQ"/>
The deformed volcanic sequences that form greenstone belts in the Canadian Shield contain hyaloclastite and pillow lavas, indicating these areas were once below sea level and the lava was rapidly cooled underwater. Pillow lavas more than two billion years old indicate large submarine volcanoes existed during the early stages of the Earth's formation.<ref name="QIE"/> |- ! Pelèan eruptions | thumb|right|Peléan eruption: 1: ash plume, 2: volcanic ash rain, 3: lava dome, 4: volcanic bomb, 5: pyroclastic flow, 6: layers of lava and ash, 7: strata, 8: magma conduit, 9: magma chamber, 10: dike || {{Main|Peléan eruption}} Peléan eruptions are violent eruptions characterized by fast-moving streams of hot volcanic gas and rock called pyroclastic flows or nuées ardentes.<ref name="ANF">{{cite book|last1=Rosi|first1=Mauro|first2=Luca|last2=Lupi|first3=Jay|last3=Hyams|first4=Paolo|last4=Papale|title=Volcanoes|publisher=Firefly Books|date= 2003|pages=56, 57|url=https://books.google.com/books?id=A60sif56pb8C&pg=PT61|isbn=978-1-55297-683-8}}</ref> Named for the stratovolcano Mount Pelée on the island of Martinique in the Caribbean Sea, Peléan eruptions occur when thick magma, typically of rhyolite, dacite and andesite type, is involved, and share some similarities with another type of explosive eruption known as Vulcanian eruptions.<ref name="ANF"/> The thick magma associated with Peléan eruptions can form lava domes and lava spines in the volcano's vent or on the volcano's summit.<ref name="ANF"/> Lava domes are steep-sided lava masses frequently circular in plan view and spiny, rounded, or flat on top.<ref name="AMC lava dome">{{cite web|publisher=USGS|url=https://vulcan.wr.usgs.gov/Glossary/Domes/description_lava_dome.html|title=Lava Domes, Volcanic Domes, Composite Domes|date=November 7, 2006|access-date=February 26, 2009|archive-date=February 24, 2013|archive-url=https://web.archive.org/web/20130224230918/http://vulcan.wr.usgs.gov/Glossary/Domes/description_lava_dome.html|url-status=dead}}</ref> If a lava dome is created, it may later collapse, forming an ash column and sending flows of ash and hot volcanic blocks down the volcano's flanks.<ref name="ANF"/> Lava spines are upright cylindrical masses of lava caused by the upward squeezing of pasty lava inside a volcanic vent.<ref name="ZIV"/> |- ! Plinian eruptions | thumb|right|Plinian eruption: 1: ash plume, 2: magma conduit, 3: volcanic ash rain, 4: layers of lava and ash, 5: stratum, 6: magma chamber || {{Main|Plinian eruption}} Plinian eruptions are large explosive eruptions that form pyroclastic flows and enormous dark columns of tephra and gas that commonly rise into the second layer of the Earth's atmosphere.<ref name="ANF"/><ref name="ACRK">{{cite web|publisher=USGS|url=https://volcanoes.usgs.gov/images/pglossary/PlinianEruption.php|title=VHP Photo Glossary: Plinian eruption|date=July 17, 2008|access-date=February 24, 2009}}</ref> Named for Roman natural philosopher Pliny the Younger, these spectacularly explosive eruptions are associated with magmas of high viscosity and gas content such as dacite and rhyolite and typically occur at calderas and stratovolcanoes.<ref name="OPE">{{cite web|publisher=Petty M. Donna |url=http://www.scetv.org/education/ntti/pdf/2004pdf/Volcanos-TharSheBlowsA2.pdf |title=Activity Sheet 2: Eruption Primer |access-date=July 5, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080717000234/http://www.scetv.org/education/ntti/pdf/2004pdf/Volcanos-TharSheBlowsA2.pdf |archive-date=July 17, 2008 }}</ref> The duration of these eruptions is highly variable, ranging from hours to days, and they commonly occur at volcanic arcs where the Earth's tectonic plates are moving towards one another, with one sliding underneath the other called a subduction zone.<ref name="OPE"/> Although Plinian eruptions typically involve magma with high levels of silica, such as dacite and rhyolite, they can occasionally occur at volcanoes characterized by passive basaltic eruptions, including shield volcanoes, when the magma chambers become differentiated and zoned to create a siliceous top. In some cases, a basaltic shield volcano may have periods of explosive activity to form a stratovolcano mounted on top of the shield volcano. An example of this activity includes the massive Level Mountain shield volcano in northwestern British Columbia, which is capped by a {{convert|860|km3|mi3|0|abbr=on}} dissected stratovolcano.<ref>{{cite gvp|vn=320050|title=Level Mountain|access-date=February 19, 2009}}</ref>
[[File:Plinth Peak north face.jpg|thumb|left|Plinth Peak of the Mount Meager massif in southwestern British Columbia is the source for a large-scale Plinian eruption that occurred 2,350 years ago, sending ash as far as Alberta]] Following massive Plinian eruptions, temperatures may decrease to cause volcanic winters. Volcanic winters are caused by volcanic ash and droplets of sulfuric acid obscuring the sun's light, usually after a volcanic eruption. A massive (VEI-7) Plinian eruption in 1815 from Mount Tambora on the island of Sumbawa, Indonesia expelled more than {{convert|150|km3|cumi|abbr=on}} of volcanic ash around the Earth, causing particularly long, dark and harsh volcanic winters in Eastern Canada from 1816 to 1818.<ref name="HJ">{{cite web|publisher=Memorial University of Newfoundland|url=http://www.heritage.nf.ca/society/scallan.html|title=Bishop Thomas Scallan (1766–1830)|access-date=December 13, 2008}}</ref> The result of this was the large amount of volcanic ash blocking out the sun's light, causing the Earth's temperature and visibility to decrease. The first volcanic winter in 1816, known as the Year Without a Summer, affected the Canadian province of Newfoundland and Labrador. In February 1816, a fire swept through St. John's, leaving 1,000 people homeless and in May during the following year, frost killed most of the crops that had been planted.<ref name="HJ"/><ref name="AP">{{cite book | last = Merrill | first = Ray M. | title = Environmental Epidemiology: Principles and Methods | publisher = Jones and Bartlett Publishers | page = 330 | url = https://books.google.com/books?id=lepqcVinM1UC&pg=RA5-PT115| isbn=978-0-7637-4152-5 | year = 2008}}</ref> In June, two large winter storms occurred throughout Eastern Canada, resulting in several casualties.<ref name="AP"/> The cause was limited amount of food supplies, and further deaths from those who, in a hunger-weakened state, then succumbed to disease.<ref name="Church-2008">{{cite web|url=http://www.firstunitarian.net/publications/sermon/reading.102608.pdf |title=The Year there Was No Summer |last=Evans |first=Catherine |date=October 26, 2008 |work=Speech in Commemoration of the dedication of a church on October 29, 1818 |access-date=April 11, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110723130009/http://www.firstunitarian.net/publications/sermon/reading.102608.pdf |archive-date=July 23, 2011 }}</ref> Nearly a foot of snow was observed in Quebec City.<ref name="AP"/> Rapid, dramatic temperature swings were common, with temperatures sometimes reverting from normal or above-normal summer temperatures as high as 35 °C to near-freezing within hours.<ref name="AP"/> In November 1817, two more fires swept through St. John's, leaving another 2,000 people poor.<ref name="HJ"/> Many who had somewhere to live had low amounts of food or fuel for heating.<ref name="HJ"/> The volcanic winters were also felt in the Maritime provinces, which includes Nova Scotia, New Brunswick and Prince Edward Island. |}
== Eastern Canada == {{Main|Volcanism of Eastern Canada}} [[File:KomatiiteCanada 682By512.jpg|thumb|right|Komatiite sample collected in the Abitibi greenstone belt near Englehart, Ontario. Specimen is {{convert|9|cm|0|abbr=on}} wide. Bladed olivine crystals are visible, though spinifex texture is weak or absent in this sample.]]
The 2,677‑million-year-old Abitibi greenstone belt in Ontario and Quebec is one of the largest Archean greenstone belts on Earth and one of the youngest parts of the Superior craton which sequentially forms part of the Canadian Shield.<ref name="ANN">{{cite web|url=http://www.nicholas.duke.edu/people/faculty/boudreau/9thPtSymposium/Sproule_Abstract.pdf|title=Geochemistry, Petrogenesis, and Metallogenisis of Komatiites in the Abitibi Greenstone Belt, Canada|first1=R. A.|last1=Sproule|first2=C. M.|last2=Lesher|first3=M. G.|last3=Houle|first4=R. R.|last4=Keays|first5=J. A.|last5=Ayer|first6=P. C.|last6=Thurson|access-date=April 11, 2009}}</ref> Komatiite lavas in the Abitibi greenstone belt (pictured) occur in four lithotectonic assemblages known as Pacaud, Stoughton-Roquemaure, Kidd-Munro and Tisdale.<ref name="ANN"/> The Swayze greenstone belt further south is interpreted to be a southwestern extension of the Abitibi greenstone belt.<ref name="GSA-2001">{{cite web|url=http://gsa.confex.com/gsa/2001AM/finalprogram/abstract_25729.htm|title=Deformation History of the Kenogamissi Batholith and the Eastern Swayze Greenstone Belt|last1=Becker|first1=J. K.|last2=Benn|first2=K.|last3=Ayer|first3=J.|date=November 8, 2001|work=Geological Society meeting background paper|publisher=Geological Society of America|access-date=April 11, 2009|archive-date=October 13, 2008|archive-url=https://web.archive.org/web/20081013212743/http://gsa.confex.com/gsa/2001AM/finalprogram/abstract_25729.htm|url-status=dead}}</ref>
The Archean Red Lake greenstone belt in western Ontario consists of basaltic and komatiitic volcanics ranging in age from 2,925 to 2,940 million years old and younger rhyolite-andesite volcanics ranging in age from 2,730 to 2,750 million years old.<ref name="LithoGreenstone">{{cite web|url=http://www.cseg.ca/conventions/abstracts/2004/2004abstracts/055S0131-Zeng_F_Abstract_Tomograpy.pdf|title=A Combined Seismic Tomographic and Reflection Imaging Across the Red Lake Greenstone Belt Using LITHOPROBE Line 2B|first1=Fafu|last1=Zeng|first2=Albert J.|last2=Calvert|work=Seismic imaging model of the Greenstone Belt|publisher=Simon Fraser University|access-date=April 11, 2009|url-status=dead|archive-url=https://web.archive.org/web/20110527152558/http://www.cseg.ca/conventions/abstracts/2004/2004abstracts/055S0131-Zeng_F_Abstract_Tomograpy.pdf|archive-date=May 27, 2011}}</ref> It is situated in the western portion of the Uchi Subprovince, a volcanic sequence comprising a number of greenstone belts.<ref>{{cite web|title=Regional Geology|work=Red Lake Gold District|publisher=Grandview Gold Inc.|url=http://www.grandviewgold.com/Gold_Properties/Red_Lake_Gold_District/?sp=Regional_Geology|access-date=February 22, 2009|url-status=dead|archive-url=https://web.archive.org/web/20100405172246/http://www.grandviewgold.com/Gold_Properties/Red_Lake_Gold_District/?sp=Regional_Geology|archive-date=April 5, 2010}}</ref>
[[File:Temagami greenstone belt pillow lava.jpg|thumb|left|Weathered Precambrian pillow lava in the Temagami Greenstone Belt of the Canadian Shield]] The 1884- to 1870‑million-year-old Circum-Superior Belt<ref>{{cite book |doi=10.1016/S0166-2635(08)70017-3 |chapter=The Circum-Superior Belt: A Proterozoic Plate Margin? |title=Developments in Precambrian Geology |year=1981 |last1=Baragar |first1=W.R.A. |last2=Scoates |first2=R.F.J. |volume=4 |pages=297–330 |isbn=978-0-444-41910-1 }}</ref> constitutes a large igneous province extending for more than {{convert|3400|km}} from the Labrador Trough in Labrador and northeastern Quebec though the Cape Smith Belt in northern Quebec, the Belcher Islands in southern Nunavut, the Fox River and Thompson belts in northern Manitoba, the Winnipegosis komatiite belt in central Manitoba, and on the southern side of the Superior craton in the Animikie Basin of northwestern Ontario.<ref name="ZZSF">{{cite web|url=http://www.largeigneousprovinces.org/04may|title=May LIP of the Month|last=Ernst|first=Richard E.|work=May "Large Igneous Province of the Month"|publisher=Large Igneous Province Commission, International Association of Volcanology and Chemistry of the Earth's Interior|access-date=April 5, 2019}}</ref><ref>{{cite journal |last1=Waterton |first1=Pedro |last2=Pearson |first2=D. Graham |last3=Kjarsgaard |first3=Bruce |last4=Hulbert |first4=Larry |last5=Locock |first5=Andrew |last6=Parman |first6=Stephen |last7=Davis |first7=Bill |title=Age, origin, and thermal evolution of the ultra-fresh ~ 1.9 Ga Winnipegosis Komatiites, Manitoba, Canada |journal=Lithos |date=January 2017 |volume=268-271 |pages=114–130 |doi=10.1016/j.lithos.2016.10.033 |bibcode=2017Litho.268..114W }}</ref><ref>{{cite journal |last1=Ciborowski |first1=T. Jake R. |last2=Minifie |first2=Matthew J. |last3=Kerr |first3=Andrew C. |last4=Ernst |first4=Richard E. |last5=Baragar |first5=Bob |last6=Millar |first6=Ian L. |title=A mantle plume origin for the Palaeoproterozoic Circum-Superior Large Igneous Province |journal=Precambrian Research |date=June 2017 |volume=294 |pages=189–213 |doi=10.1016/j.precamres.2017.03.001 |bibcode=2017PreR..294..189C |doi-access=free }}</ref> Two volcano-sedimentary sequences exist in the Labrador Trough with ages of 2,170–2,140 million years and 1,883–1,870 million years.<ref name="ZZSF"/> In the Cape Smith Belt, two volcanic groups range in age from 2,040 to 1,870 million years old called the Povungnituk volcano-sedimentary Group and the Chukotat Group.<ref name="ZZSF"/> The Belcher Islands in eastern Hudson Bay contain two volcanic sequences known as the Flaherty and Eskimo volcanics.<ref name="ZZSF"/> The Fox River Belt consists of volcanics, sills and sediments some 1,883 million years old while magmatism of the Thompson Belt is dated to 1,880 million years old.<ref name="ZZSF"/> To the south lies the 1,864‑million-year-old Winnipegosis komatiites.<ref name="ZZSF"/> In the Animikie Basin near Lake Superior, volcanism is dated 1,880 million years old.<ref name="ZZSF"/>
[[File:Mount McKay Thunder Bay.jpg|thumb|right|Mount McKay, a mafic sill related to volcanism of the Midcontinent Rift System in Thunder Bay, Ontario.]] During the Mesoproterozoic era of the Precambrian eon 1,109 million years ago, northwestern Ontario began to split apart to form the Midcontinent Rift System, also called the Keweenawan Rift.<ref name="ALR">{{cite web|url=http://www.uwm.edu/~wkean/fieldtrip/ArCraig/keewenaw.htm|title=Keweenawan Rift System|work=Field Trip to Keweenawan Rift System-results|access-date=April 11, 2009|url-status=dead|archive-url=https://web.archive.org/web/20070317041722/http://www.uwm.edu/~wkean/fieldtrip/ArCraig/keewenaw.htm|archive-date=March 17, 2007}}</ref> Lava flows created by the rift in the Lake Superior area were formed from basaltic magma.<ref name="ALR"/> The upwelling of this magma was the result of a hotspot which produced a triple junction in the vicinity of Lake Superior. The hotspot made a dome that covered the Lake Superior area.<ref name="ALR"/> Voluminous basaltic lava flows erupted from the central axis of the rift, similar to the rifting that formed the Atlantic Ocean.<ref name="ALR"/> A ''failed arm'' extends {{convert|150|km}} north into mainland Ontario where it forms a geological formation known as the Nipigon Embayment.<ref name="ZQP">{{cite web|url=http://www.vip-gac.ca/Ashfall/Ashfall65.pdf|title=ASH FALL - Newsletter of the Volcanology and Igneous Petreology Division Geological Association of Canada|date=June 11, 2007|work=Newsletter of Canadian Volcanology and Geology no. 65|publisher=ASH FALL|access-date=April 11, 2009}}</ref> This failed arm includes Lake Nipigon, the largest lake entirely within the boundaries of Ontario.<ref name="ZQP"/>
[[File:st-hilaire2.jpg|thumb|right|Mont Saint-Hilaire, an intrusive mountain of the Monteregian Hills in southern Quebec formed by the New England hotspot]] Periods of volcanic activity occurred throughout central Canada during the Jurassic and Cretaceous periods. The source for this volcanism was a long-lived and stationary area of molten rock called the New England or Great Meteor hotspot.<ref name="BRM">{{cite web|publisher=Geological Survey of Canada|url=http://dsp-psd.pwgsc.gc.ca/Collection-R/GSC-CGC/M44-2001/M44-2001-F3E.pdf|title=A Late Triassic Rb-Sr phlogopite isochron age for a kimberlite dyke from the Rankin Inlet area, Nunavut|year=2001|access-date=February 28, 2009|archive-date=December 23, 2007|archive-url=https://web.archive.org/web/20071223051359/http://dsp-psd.pwgsc.gc.ca/Collection-R/GSC-CGC/M44-2001/M44-2001-F3E.pdf|url-status=dead}}</ref> The first event erupted kimberlite magma in the James Bay lowlands region of northern Ontario 180 million years ago, creating the Attawapiskat kimberlite field.<ref name="BRM"/> Another kimberlite event spanned a period of 13 million years 165 to 152 million years ago, creating the Kirkland Lake kimberlite field in northeastern Ontario.<ref name="BRM"/> Another period of kimberlite volcanism occurred in northeastern Ontario 154 to 134 million years ago, creating the Lake Timiskaming kimberlite field.<ref name="BRM"/> As the North American Plate moved westward over the New England hotspot, the New England hotspot created the magma intrusions of the Monteregian Hills in Montreal in southern Quebec.<ref name="AAAH">{{cite web|publisher=NOAA|url=http://www.oceanexplorer.noaa.gov/explorations/05stepstones/background/geologic_history/geologic_history.html|title=A Hundred-Million Year History of the Corner Rise and New England Seamounts|date=August 10, 2005|access-date=February 18, 2009|archive-url=https://web.archive.org/web/20130708095650/http://oceanexplorer.noaa.gov/explorations/05stepstones/background/geologic_history/geologic_history.html|archive-date=July 8, 2013|url-status=dead|df=mdy-all}}</ref> These intrusive stocks have been variously interpreted as the feeder intrusions of long extinct volcanoes that would have been active 125 million years ago, or as intrusions that never breached the surface in volcanic activity.<ref name="AAAH"/><ref>{{cite web|title=A geological heritage to discover|work=Geoscape Montreal|publisher=Geoscape Canada|date=January 2, 2008|url=http://geoscape.nrcan.gc.ca/montreal/heritage_e.php|access-date=February 28, 2009|url-status=dead|archive-url=https://web.archive.org/web/20090426185205/http://geoscape.nrcan.gc.ca/montreal/heritage_e.php|archive-date=April 26, 2009}}</ref> The lack of a noticeable hotspot track west of the Monteregian Hills might be due either to failure of the New England mantle plume to pass through massive strong rock of the Canadian Shield, the lack of noticeable intrusions, or to strengthening of the New England mantle plume when it approached the Monteregian Hills region.<ref name="Monteregian Hills-1990">{{cite journal|last=Sleep|first=Norman H.|date=December 1990|title=Monteregian hotspot track: A long-lived mantle plume|journal=Journal of Geophysical Research|publisher=AGU|volume= 95|issue= B13|pages=21983–21990|bibcode=1990JGR....9521983S|doi=10.1029/JB095iB13p21983}}</ref>
thumb|left|Basal contact of a lava flow section of the Fundy Basin About 250 million years ago during the early Triassic period, Atlantic Canada lay roughly in the middle of a giant continent called Pangaea.<ref name="AAY">{{cite web|url= http://earthnet-geonet.ca/vft/ns/fiveislands/fiveislands.pdf|title=Five Islands Provincial Park|work=Brochure on Five Islands Provincial Park|access-date=April 11, 2009 |archive-url = https://web.archive.org/web/20070317003508/http://earthnet-geonet.ca/vft/ns/fiveislands/fiveislands.pdf|archive-date = March 17, 2007}}</ref> This supercontinent began to fracture 220 million years ago when the Earth's lithosphere was being pulled apart from extensional stress, creating a divergent plate boundary known as the Fundy Basin.<ref name="AAY"/> The focus of the rifting began somewhere between where present-day eastern North America and northwestern Africa were joined. During the formation of the Fundy Basin, volcanic activity never stopped as shown by the going eruption of lava along the Mid-Atlantic Ridge; an underwater volcanic mountain range in the Atlantic Ocean formed as a result of continuous seafloor spreading between eastern North America and northwestern Africa. As the Fundy Basin continued to form 201 million years ago, a series of basaltic lava flows were erupted, forming a volcanic mountain range on the mainland portion of southwestern Nova Scotia known as North Mountain, stretching {{convert|200|km}} from Brier Island in the south to Cape Split in the north.<ref name="JointRev-2007">{{cite web|url=http://www.ceaa.gc.ca/010/0001/0001/0023/001/WP-1783-026.pdf|title=Public hearing of Joint Review Panel for the Environmental Assessment of Whites Point Quarry and Marine Terminal Project|last=Jones|first=Jon|date=June 11, 2007|work=Joint Review- wildlife review assessment and comments|publisher=Nova Scotia Department of Natural Resources|access-date=April 11, 2009|archive-date=November 22, 2007|archive-url=https://web.archive.org/web/20071122102224/http://www.ceaa.gc.ca/010/0001/0001/0023/001/WP-1783-026.pdf|url-status=dead}}</ref> This series of lava flows cover most of the Fundy Basin and extend under the Bay of Fundy where parts of it are exposed on the shore at the rural community of Five Islands, east of Parrsboro on the north side of the bay. Large dikes {{convert|4|to(-)|30|m|ft|0}} wide exist throughout southernmost New Brunswick with ages and compositions similar to the North Mountain basalt, indicating these dikes were the source for North Mountain lava flows.<ref name="CAMP"/> However, North Mountain is the remnants of a larger volcanic feature that has now been largely eroded based on the existence of basin border faults and erosion.<ref name="CAMP"/> The hard basaltic ridge of North Mountain resisted the grinding of ice sheets that flowed over this region during the past ice ages, and now forms one side of the Annapolis Valley in the western part of the Nova Scotia peninsula. The layering of a North Mountain lava flow less than {{convert|175|m}} thick at McKay Head, closely resemble that of some Hawaiian lava lakes, indicating Hawaiian eruptions occurred during the formation of North Mountain.<ref name="CAMP">{{cite web|url=http://earth2geologists.net/grandmanangeology/NorthMountainBasaltSources.pdf|title=Fissure Dike Source(s) For the North Mountain Basalt Group, Fundy Basin|publisher=J. Gregory McHone, Sandra M. Barr|access-date=April 11, 2009}}</ref>
thumb|right|Satellite image of the Newfoundland Seamounts. The Fogo Seamounts, located {{convert|500|km|mi|0|abbr=on}} offshore of Newfoundland to the southwest of the Grand Banks, consists of submarine volcanoes with dates extending back to the Early Cretaceous period at least 143 million years ago.<ref name="QQI">{{cite conference |last1=Pe-Piper |first1=G. |last2=de Jonge |first2=A. |last3=Piper |first3=D. J. W. |last4=Jansa |first4=L. F. |title=Morphology, petrography, age and origin of Fogo Seamount chain, offshore eastern Canada |date=1 April 2003 |pages=2020 |conference=EGS - AGU - EUG Joint Assembly |bibcode=2003EAEJA.....2020P |url=http://www.cosis.net/abstracts/EAE03/02020/EAE03-J-02020.pdf |access-date=3 March 2009 |archive-date=3 March 2016 |archive-url=https://web.archive.org/web/20160303225841/http://www.cosis.net/abstracts/EAE03/02020/EAE03-J-02020.pdf |url-status=dead }}</ref> They may have one or two origins. The Fogo Seamounts could have formed along fracture zones in the Atlantic seafloor because of the large number of seamounts on the North American continental shelf.<ref name="QQI"/> The other explanation for their origin is they formed above a mantle plume associated with the Canary or Azores hotspots in the Atlantic Ocean, based on the existence of older seamounts to the northwest and younger seamounts to the southeast.<ref name="QQI"/> The existence of flat-topped seamounts throughout the Fogo Seamount chain indicate some of these seamounts would once have stood above sea level as islands that would have been volcanically active. Their flatness is due to coastal erosion, such as waves and winds.<ref name="QQI"/> Other submarine volcanoes offshore of Eastern Canada include the poorly studied Newfoundland Seamounts.<ref name="QQI"/>
== Western Canada == {{Main|Volcanism of Western Canada}} The Flin Flon greenstone belt in central Manitoba and east-central Saskatchewan is a collage of deformed volcanic arc rocks ranging in age from 1,904 to 1,864 million years old during the Paleoproterozoic sub-division of the Precambrian eon.<ref name=Stern>{{cite journal |last1=Stern |first1=Richard A. |last2=Syme |first2=Eric C. |last3=Bailes |first3=Alan H. |last4=Lucas |first4=Stephen B. |title=Paleoproterozoic (1.90–1.86 Ga) arc volcanism in the Flin Flon Belt, Trans-Hudson Orogen, Canada |journal=Contributions to Mineralogy and Petrology |date=March 1995 |volume=119 |issue=2–3 |pages=117–141 |doi=10.1007/BF00307276 |bibcode=1995CoMP..119..117S |s2cid=128985576 }}</ref> Volcanic activity between 1,890 and 1,864 million years ago produced calc-alkaline andesite-rhyolite magmas and rare shoshonite and trachyandesite magmas while the 1,904‑million-year-old arc volcanism occurred in one or more separate volcanic arcs that were possibly characterized by rapid subduction of thin oceanic crust and large back-arc basins.<ref name="Stern"/> In contrast, the younger 1,890‑million-year-old volcanics indicate evidence of crustal thickening.<ref name="Stern"/> This was due to long-term growth of the volcanic arcs by continuous volcanic activity and tectonic thickening associated with arc collisions and successive arc deformation.<ref name="Stern"/> This in turn followed a massive mountain building event called the Trans-Hudson orogeny.
The Cretaceous period 145-66 million years ago was a period for active kimberlite volcanism in the Western Canadian Sedimentary Basin of Alberta and Saskatchewan. The Fort à la Corne kimberlite field in central Saskatchewan formed 104 to 95 million years ago during the Early Cretaceous.<ref name="AHKV"/> Unlike most kimberlite fields on Earth, the Fort à la Corne kimberlite field formed during more than one eruptive event.<ref>{{cite web|url=http://www.cosis.net/abstracts/9IKC/00364/9IKC-A-00364-1.pdf|title=Geology and Diamonds: The Star and Orion South Kimberlites, Fort á la|first1=S.|last1=Harvey|first2=M.|last2=Shimell|first3=L.|last3=Fourie|first4=P.|last4=Du Plessis|first5=G.|last5=Reed|first6=B.|last6=Kjarsgaard|year=2008|work=9th International Kimberlite Conference Extended Abstract|publisher=9th International Kimberlite Conference|access-date=April 13, 2009|archive-date=March 3, 2016|archive-url=https://web.archive.org/web/20160303182155/http://www.cosis.net/abstracts/9IKC/00364/9IKC-A-00364-1.pdf|url-status=dead}}</ref> Its kimberlites are among the most complete examples on Earth, preserving kimberlite pipes and maar volcanoes.<ref>{{Cite web |url=http://www.er.gov.sk.ca/adx/aspx/adxGetMedia.aspx?DocID=4370,3574,3442,3440,3385,5460,2936,Documents&MediaID=8690&Filename=zonneveld.pdf |title=Sedimentary Constraints on Kimberlite Emplacement in the Fort à la Corne Kimberlite Field |access-date=2008-09-21 |archive-date=2011-07-25 |archive-url=https://web.archive.org/web/20110725050513/http://www.er.gov.sk.ca/adx/aspx/adxGetMedia.aspx?DocID=4370,3574,3442,3440,3385,5460,2936,Documents&MediaID=8690&Filename=zonneveld.pdf |url-status=dead }}</ref> The Northern Alberta kimberlite province consists of three kimberlite fields known as the Birch Mountains, Buffalo Head Hills and the Mountain Lake cluster.<ref name="AKWR">{{cite web|url=http://www.ags.gov.ab.ca/minerals/diamonds/8ikc_abstract.pdf |title=Microsoft Word - revised 20 November 2002 8IKC Long Abstract Eccles.doc |access-date=June 30, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20110526054242/http://www.ags.gov.ab.ca/minerals/diamonds/8ikc_abstract.pdf |archive-date=May 26, 2011 }}</ref> The Birch Mountains kimberlite field consists of eight kimberlite pipes known as Phoenix, Dragon, Xena, Legend and Valkyrie, dating approximately 75 million years old.<ref name="AKWR"/> The Buffalo Head Hills kimberlite field was dominated by explosive kimberlite volcanism from 88 million years ago to 81 million years ago, forming maars.<ref name="AHKV">{{cite book |last1=Boyer |first1=L |last2=McCandless |first2=T |last3=Tosdal |first3=R |last4=Russell |first4=K |chapter=Volcanic facies and eruption styles in the Cretaceous Buffalo Head Hills kimberlites, Alberta, Canada |doi=10.29173/ikc3584 |title=International Kimberlite Conference Extended Abstracts |year=2008 |isbn=978-1-55195-423-3 }}</ref> Kimberlites of the Buffalo Head Hills field are similar to those associated with the Fort à la Corne kimberlite field in central Saskatchewan.<ref name="AHKV"/> The kimberlite pipes of the Mountain Lake cluster were formed during a similar timespan with the Birch Mountains field 77 million years ago.<ref name="AKWR"/>
=== Formation of the Pacific Northwest === {{Main|Geology of the Pacific Northwest}} thumb|right|Plate tectonics of the Intermontane Islands arc 195 million years ago. The Canadian portion of the Pacific Northwest began forming during the early Jurassic period when a group of active volcanic islands collided against a pre-existing continental margin and coastline of Western Canada.<ref name="SI">{{cite web|publisher=Burke Museum of Natural History and Culture|url=http://www.washington.edu/burkemuseum/geo_history_wa/The%20Omineca%20Episode.htm|title=The Omineca Episode (180 - 115 million years ago)|access-date=December 12, 2008}}</ref> These volcanic islands, known as the Intermontane Islands by geoscientists, were formed on a pre-existing tectonic plate called the Intermontane Plate about 245 million years ago by subduction of the former Insular Plate to its west during the Triassic period.<ref name="SI"/> This subduction zone records another subduction zone called the Intermontane Trench under an ancient ocean between the Intermontane Islands and the former continental margin of Western Canada called the Slide Mountain Ocean.<ref name="SI"/> This arrangement of two parallel subduction zones is unusual in that very few twin subduction zones exist on Earth; the Philippine Mobile Belt off the eastern coast of Asia is an example of a modern twin subduction zone.<ref name="SI"/> As the Intermontane Plate drew closer to the pre-existing continental margin by ongoing subduction under the Slide Mountain Ocean, the Intermontane Islands drew closer to the former continental margin and coastline of Western Canada, supporting a volcanic arc on the former continental margin of Western Canada.<ref name="SI"/> As the North American Plate drifted west and the Intermontane Plate continued to drift east to the ancient continental margin of Western Canada, the Slide Mountain Ocean began to close by ongoing subduction under the Slide Mountain Ocean.<ref name="SI"/> This subduction zone eventually jammed and shut down completely about 180 million years ago, ending the arc volcanism on the ancient continental margin of Western Canada and the Intermontane Islands collided, forming a long chain of deformed volcanic and sedimentary rock called the Intermontane Belt, which consists of deeply cut valleys, high plateaus, and rolling uplands.<ref name="SI"/> This collision also crushed and folded sedimentary and igneous rocks, creating a mountain range called the Kootenay Fold Belt which existed in far eastern British Columbia.<ref name="SI"/>
thumb|left|Plate tectonics of the Omineca and Insular arcs 130 million years ago. After the sedimentary and igneous rocks were folded and crushed, it resulted in the creation of a new continental shelf and coastline.<ref name="SI"/> The Insular Plate continued to subduct under the new continental shelf and coastline about 130 million years ago during the mid Cretaceous period after the formation of the Intermontane Belt, supporting a new continental volcanic arc called the Omineca Arc.<ref name="SI"/> Magma rising from the Omineca Arc successfully connected the Intermontane Belt to the mainland of Western Canada, forming a chain of volcanoes in British Columbia that existed discontinuously for about 60 million years.<ref name="SI"/> The ocean lying offshore during this period is called the Bridge River Ocean.<ref name="SI"/> It was also during this period when another group of active volcanic islands existed along the newly built continental shelf and coastline.<ref name="AD"/> These volcanic islands, known as the Insular Islands, were formed on the Insular Plate by subduction of the former Farallon Plate to its west during the early Paleozoic era.<ref name="AD"/> As the North American Plate drifted west and the Insular Plate drifted east to the continental margin of Western Canada, the Bridge River Ocean began to close by ongoing subduction under the Bridge River Ocean.<ref name="AD">{{cite web|publisher=Burke Museum of Natural History and Culture|url=http://www.washington.edu/burkemuseum/geo_history_wa/Coast%20Range%20Episode.htm |title=The Coast Range Episode (115 to 57 million years ago)|access-date=April 9, 2008}}</ref> This subduction zone eventually jammed and shut down completely 115 million years ago, ending the Omineca Arc volcanism and the Insular Islands collided, forming the Insular Belt.<ref name="AD"/> Compression resulting from this collision crushed, fractured and folded rocks along the continental margin.<ref name="AD"/> The Insular Belt then welded onto the continental margin by magma that eventually cooled to create a large mass of igneous rock, creating a new continental margin.<ref name="AD"/> This large mass of igneous rock is the largest granite outcropping in North America.<ref name="AD"/>
thumb|right|Plate tectonics of the Coast Range Arc 100 million years ago. The Farallon Plate continued to subduct under the new continental margin of Western Canada after the Insular Plate and Insular Islands collided with the former continental margin, supporting a new chain of volcanoes on the mainland of Western Canada called the Coast Range Arc about 100 million years ago during the Late Cretaceous epoch.<ref name="KO">{{cite book | last = Stowell | first = Harold H. |author2=McClelland William C. | title = Tectonics of the Coast Mountains, Southeastern Alaska and British Columbia |publisher = Geological Society of America |date= 2000|page = 101 |url = https://books.google.com/books?id=5SgAthT0MuAC|isbn = 978-0-8137-2343-3}}</ref> Magma ascending from the Farallon Plate under the new continental margin burned their way upward through the newly accreted Insular Belt, injecting huge quantities of granite into older igneous rocks of the Insular Belt.<ref name="AD"/> At the surface, new volcanoes were built along the continental margin.<ref name="AD"/> The basement of this arc was likely Early Cretaceous and Late Jurassic age intrusions from the Insular Islands.<ref name="KO"/>
thumb|left|Plate tectonics of the Coast Range Arc about 75 million years ago One of the major aspects that changed early during the Coast Range Arc was the status of the northern end of the Farallon Plate, a portion now known as the Kula Plate.<ref name="AD"/> About 85 million years ago, the Kula Plate broke off from the Farallon Plate to form an area of seafloor spreading called the Kula-Farallon Ridge.<ref name="AD"/> This change apparently had some important ramifications for regional geologic evolution. When this change was completed, Coast Range Arc volcanism returned and sections of the arc were uplifted considerably in latest Cretaceous time.<ref name="coast origins">{{cite book|first1=Virginia|last1=Baker Sisson|first2=Sarah|last2=Melissa Roeske|first3=Terry L.|last3=Pavlis|title=Geology of a Transpressional Orogen Developed During Ridge-trench Interaction Along the North Pacific Margin|url=https://books.google.com/books?id=AAZBokqaWj8C&pg=PA66|year=2003|publisher=Geological Society of America|isbn=978-0-8137-2371-6|page=66}}</ref> This started a period of mountain building that affected much of western North America called the Laramide orogeny.<ref name="AV">{{cite web|title=Laramide orogeny |publisher=Encyclopædia Britannica, Inc. |year=1998 |url=http://tlacaelel.igeofcu.unam.mx/~GeoD/colision/figs/orogeny/laramide.html |access-date=December 13, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20090526224324/http://tlacaelel.igeofcu.unam.mx/~GeoD/colision/figs/orogeny/laramide.html |archive-date=May 26, 2009 }}</ref> In particular a large area of dextral transpression and southwest-directed thrust faulting was active from 75 to 66 million years ago.<ref name="SI"/> Much of the record of this deformation has been overridden by Tertiary age structures and the zone of Cretaceous dextral thrust faulting appears to have been widespread.<ref name="SI"/> It was also during this period when massive amounts of molten granite intruded highly deformed ocean rocks and assorted fragments from pre-existing island arcs, largely remnants of the Bridge River Ocean.<ref name="AD"/> This molten granite burned the old oceanic sediments into a glittering medium-grade metamorphic rock called schist.<ref name="AD"/> The older intrusions of the Coast Range Arc were then deformed under the heat and pressure of later intrusions, turning them into layered metamorphic rock known as gneiss.<ref name="AD"/> In some places, mixtures of older intrusive rocks and the original oceanic rocks have been distorted and warped under intense heat, weight and stress to create unusual swirled patterns known as migmatite, appearing to have been nearly melted in the procedure.<ref name="AD"/>
Volcanism began to decline along the length of the arc about 60 million years ago during the Albian and Aptian faunal stages of the Cretaceous period.<ref name="KO"/> This resulted from the changing geometry of the Kula Plate, which progressively developed a more northerly movement along the mainland of Western Canada.<ref name="AD"/> Instead of subducting beneath Western Canada, the Kula Plate began subducting underneath southwestern Yukon and Alaska during the early Eocene period.<ref name="AD"/> Volcanism along the entire length of the Coast Range Arc shut down about 50 million years ago and many of the volcanoes have disappeared from erosion.<ref name="AD"/> What remains of the Coast Range Arc to this day are outcrops of granite when magma intruded and cooled at depth beneath the volcanoes, forming the Coast Mountains.<ref name="AD"/> During construction of intrusions 70 and 57 million years ago, the northern motion of the Kula Plate might have been between {{convert|140|mm|in|0|abbr=on}} and {{convert|110|mm|in|0|abbr=on}} per year.<ref name="KC">{{cite web|publisher=University of Arizona|url=http://www.geo.arizona.edu/tectonics/Ducea/Batholiths/Tectonics.htm|title=Tectonic overview of the CPC|access-date=September 7, 2008|archive-date=August 28, 2008|archive-url=https://web.archive.org/web/20080828014045/http://www.geo.arizona.edu/tectonics/Ducea/Batholiths/Tectonics.htm|url-status=dead}}</ref> However, other geologic studies determined the Kula Plate moved at a rate as fast as {{convert|200|mm|in|0|abbr=on}} per year.<ref name="KC"/>
=== Cascadia subduction zone complexes === {{Main|Cascadia subduction zone}} thumb|right|Structure of the Cascadia subduction zone As the last of the Kula Plate decayed and the Farallon Plate advanced back into this area from the south, it once again started to subduct under the continental margin of Western Canada 37 million years ago, supporting a chain of volcanoes called the Cascade Volcanic Arc. At least four volcanic formations along the British Columbia Coast are associated with Cascadia subduction zone volcanism.<ref name="SLV">{{cite book|last=Wood | first=Charles A. |author2=Kienle, Jürgen| pages=111, 112, 113, 114, 115, 124, 126, 135, 136 | title=Volcanoes of North America: United States and Canada | year=1990 | publisher=Cambridge University Press | location=Cambridge, England| isbn= 0-521-43811-X}}</ref> The oldest is the eroded 18-million-year-old Pemberton Volcanic Belt which extends west-northwest from south-central British Columbia to Haida Gwaii in the northeast where it lies {{convert|150|km}} west of mainland British Columbia.<ref name="SLV"/> In the south it is defined by a group of epizonal intrusions and a few erosional remnants of eruptive rock.<ref name="SLV"/> Farther north in the large Ha-Iltzuk and Waddington icefields, it includes two large dissected calderas called Silverthrone Caldera and Franklin Glacier Complex while Haida Gwaii to the northeast contains a volcanic formation ranging in age from Miocene to Pliocene called the Masset Formation.<ref name="SLV"/> Although widely separated from each other, all Pemberton Belt rocks are of similar age and have similar magma compositions.<ref name="SLV"/> Therefore, these magmatic rocks are believed to be products of arc volcanism related to subduction of the Farallon Plate.<ref name="SLV"/> By late Pliocene time the Farallon Plate had been greatly reduced in size and its northern portion ultimately broke off between five and seven million years ago to form a new plate boundary called the Nootka Fault. This rupture created the two small Juan de Fuca and Explorer plates that lie off the west coast of Vancouver Island.
thumb|right|Map of the Garibaldi Volcanic Belt [[File:Pyroclastic and Cayley.jpg|thumb|right|The Mount Cayley massif on August 13, 2005. Summits left to right are Pyroclastic Peak and Mount Cayley.]] The four-million-year-old Garibaldi Volcanic Belt, a north-south trending zone of volcanoes and volcanic rock in the southern Coast Mountains of southwestern British Columbia, can be grouped into at least three enechelon segments, referred to as the northern, central, and southern segments.<ref name="SLV"/> The northern segment overlaps the older Pemberton Volcanic Belt at a low angle near the Mount Meager massif where Garibaldi Belt lavas rest on uplifted and deeply eroded remnants of Pemberton Belt subvolcanic intrusions and combines to form a single belt.<ref name="SLV"/> A few isolated volcanoes northwest of the Mount Meager massif, such as Silverthrone Caldera and Franklin Glacier Complex, are also grouped as part of the Garibaldi Volcanic Belt.<ref name="QIP">{{cite journal |last1=Kelman |first1=M. C. |last2=Russell |first2=J. K. |last3=Hickson |first3=C. J. |title=Effusive intermediate glaciovolcanism in the Garibaldi Volcanic Belt, southwestern British Columbia, Canada |journal=Geological Society, London, Special Publications |date=2002 |volume=202 |issue=1 |pages=195–211 |doi=10.1144/GSL.SP.2002.202.01.10 |bibcode=2002GSLSP.202..195K |s2cid=128759766 }}</ref><ref name="AIO">{{cite web|title=Garibaldi volcanic belt |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=February 13, 2008 |url=http://cgc.rncan.gc.ca/volcanoes/cat/belt_garibaldi_e.php |access-date=May 10, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20061023030758/http://cgc.rncan.gc.ca/volcanoes/cat/belt_garibaldi_e.php |archive-date=October 23, 2006 }}</ref><ref name="Green & Sinha 2005">{{cite journal |last1=Green |first1=Nathan L. |last2=Sinha |first2=A. Krishna |title=Consequences of varied slab age and thermal structure on enrichment processes in the sub-arc mantle of the northern Cascadia subduction system |journal=Journal of Volcanology and Geothermal Research |date=January 2005 |volume=140 |issue=1–3 |pages=107–132 |doi=10.1016/j.jvolgeores.2004.07.017 |bibcode=2005JVGR..140..107G }}</ref> However, their tectonic origins are largely unexplained and are a matter of going research. When the Farallon Plate ruptured to create the Nootka Fault between five and seven million years ago, there were some apparent changes along the Cascadia subduction zone. At issue is the current plate configuration and rate of subduction but based on rock composition is for Silverthrone Caldera and Franklin Glacier Complex to be subduction related.<ref name="AIO"/><ref name="Green & Sinha 2005"/> The roughly circular, {{convert|20|km}} wide, deeply dissected Silverthrone Caldera in the northern segment of the Garibaldi Volcanic Belt, was formed one million years ago during the Early Pleistocene period.<ref name="QIP"/> The bulk of the volcano was erupted 0.4 million years ago, but younger phases, consisting of lava flows and subsidiary volcanoes with compositions of andesite and basaltic andesite are also present.<ref name="QIP"/><ref name="ASB">{{cite gvp|vn=320160|title=Silverthrone|access-date=July 15, 2008}}</ref> Silverthrone Mountain, an eroded lava dome on the northeast edge of Silverthrone Caldera, was episodically active during both Pemberton and Garibaldi stages of volcanism.<ref name="SLV"/> The eroded Franklin Glacier Complex just to the southeast consists of dacite and andesite rocks that range in age from 3.9 to 2.2 million years old.<ref name="QIP"/> Southeast of Franklin Glacier Complex, the Bridge River Cones comprise remnants of both andesitic and alkali basalt cones and lava flows.<ref name="SLV"/> These range in age from about one million years old to 0.5 million years old and commonly display ice-contact features related to subglacial eruptions.<ref name="SLV"/> The Mount Meager massif, the most persistent volcano in the northern portion of the Garibaldi Volcanic Belt, is a complex of at least four overlapping stratovolcanoes made of dacite and rhyodacite that become progressively younger from south to north, ranging in age from two million to 2,490 years old.<ref name="SLV"/> The central segment of the Garibaldi Volcanic Belt is defined by a group of eight volcanoes on a ridge of highland east of the Squamish River, and by remnants of basaltic lava flows preserved in the adjacent Squamish valley.<ref name="SLV"/> Mount Cayley, the largest and most persistent volcano, is a deeply eroded stratovolcano comprising a lava dome complex made of dacite and minor rhyodacite ranging in age from 3.8 to 0.31 million years old.<ref name="SLV"/> Mount Fee, a narrow volcanic plug made of rhyodacite about {{convert|1|km|ft}} long and {{convert|250|m}} wide, rises {{convert|150|m}} above the highland ridge.<ref name="SLV"/> Complete denudation of the central spine as well as the absence of till under lava flows from Mount Fee suggest a preglacial age.<ref name="SLV"/> The other volcanoes of the central Garibaldi Belt, including Ember Ridge, Pali Dome, Cauldron Dome, Slag Hill, Mount Brew and Crucible Dome, were formed during subglacial eruptions to develop tuya-like forms with over-steepened, ice-contact margins.<ref name="SLV"/> The primary volcanoes in the southern segment are Mount Garibaldi, Mount Price, and The Black Tusk.<ref name="SLV"/> The oldest volcano, The Black Tusk, is the remnants of an extinct andesitic stratovolcano that formed during two distant stages of volcanic activity, the first between 1.1 and 1.3 million years ago and the second between 0.17 and 0.21 million years ago.<ref name="SLV"/> Mount Garibaldi, a fairly dissected stratovolcano {{convert|80|km}} north of Vancouver, was built by Peléan eruptions between 0.26 and 0.22 million years ago during the waning stages of the last glacial, or "Wisconsinian", period.<ref name="SLV"/> Mount Price, a less significant stratovolcano just north of Mount Garibaldi, formed during three distinct periods of volcanic activity beginning at 1.2 million years ago and culminating with the eruption of Clinker Peak on its western flank 0.3 million years ago.<ref name="SLV"/> In addition to the large, central andesite-dacite volcanoes, the southern portion of the Garibaldi Volcanic Belt includes remnants of basalt and basaltic andesite lava flows and pyroclastic rocks.<ref name="SLV"/> These include valley -filling lava flows interbedded with till containing wood about 34,000 years old.<ref name="SLV"/>
The poorly studied Alert Bay Volcanic Belt extends from Brooks Peninsula on the northwestern coast of Vancouver Island to Port McNeill on the northeastern coast of Vancouver Island.<ref name="SLV"/> It encompasses several separate remnants of late Neogene volcanic piles and related intrusions ranging in composition from basalt to rhyolite and in age from about eight million years old in the west to about 3.5 million years old elsewhere.<ref name="SLV"/> Major element analyses of Alert Bay volcanic and hypabyssal rocks suggest two different basalt-andesite-dacite-rhyolite suites with divergent fractionation trends.<ref name="SLV"/> The first coincides with the typical calc-alkaline, Cascade trend, whereas the other is more alkaline and more Fe-enriched following a trend which straddles the calc-alkaline-tholeiite boundary.<ref name="SLV"/> The western end of the Alert Bay Volcanic Belt is now about {{convert|80|km}} northeast of the Nootka Fault.<ref name="SLV"/> However, at the time of its formation the volcanic belt may have been coincident with the subducted plate boundary.<ref name="SLV"/> Also, the timing of volcanism corresponds to shifts of plate motion and changes in the locus of volcanism along the Pemberton and Garibaldi volcanic belts.<ref name="SLV"/> This brief interval of plate motion adjustment at about 3.5 million years ago may have triggered the generation of basaltic magma along the descending plate edge.<ref name="SLV"/> Because the Alert Bay Volcanic Belt has not been active for at least 3.5 million years, volcanism in the Alert Bay Volcanic Belt is probably extinct.<ref>{{cite book|last=Casadevall|first=Thomas J.|title=Volcanic Ash And Aviation Safety: Proceedings of the First International Symposium on Volcanic Ash and Aviation Safety |publisher=DIANE Publishing|year=1991|page=50|url=https://books.google.com/books?id=pKY_VLqMTgsC&pg=PA50| isbn=978-0-7881-1650-6}}</ref>
thumb|right|Cliffs made of lava flows from former extensive volcanic activity in the Chilcotin Group. The Chilcotin Group, a {{convert|50000|km2|sqmi|abbr=on}} large igneous province and volcanic plateau in south-central British Columbia, consists of thin, flat-lying, poorly formed columnar basalt lava flows that have formed as a result of partial melting in a weak zone in the upper part of the Earth's mantle within a back-arc basin related to subduction of the Juan de Fuca Plate.<ref name="SLV"/> Chilcotin Group volcanism occurred in three distant magmatic episodes, the first 16-14 million years ago, the seconed 10-6 million years ago and the third 3-1 million years ago.<ref name="SLV"/> Anahim Peak, a volcanic plug near the eastern flank of the Rainbow Range, and other plugs penetrating the Chilcotin Group are suggested to be vents for basalt volcanism.<ref name="SLV"/> These volcanic plugs form a northwest trend about {{convert|150|km}} inland from the Pemberton and Garibaldi volcanic belts and exist along the axis of the volcanic plateau.<ref name="SLV"/> Silicic tuff lying between Chilcotin basalt lava flows, likely originated from explosive eruptions related to arc volcanism in the Garibaldi and Pemberton belts just to the west and was preserved between successive basaltic lava eruptions in the Chilcotin back-arc basin.<ref name="SLV"/> It is suggested by geoscientists the Chilcotin Group forms a sequence of merged low-profile shield volcanoes erupted from central vents.<ref name="SLV"/>
===British Columbia plume and rift complexes=== thumb|right|Map of the Northern Cordilleran Volcanic Province. The Northern Cordilleran Volcanic Province of northwestern British Columbia, also called the Stikine Volcanic Belt, is the most active volcanic region in Canada.<ref name="ZAM">{{cite web|title=Stikine volcanic belt|work=Catalogue of Canadian volcanoes|publisher=Geological Survey of Canada|date=February 13, 2008|url=http://gsc.rncan.gc.ca/volcanoes/cat/belt_stikine_e.php|access-date=February 21, 2009}}{{dead link|date=September 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> It comprises a large number of small cinder cones and associated lava plains, and three large, compositionally diverse volcanoes, known as the Level Mountain, the Mount Edziza volcanic complex, and Hoodoo Mountain.<ref name="SLV"/> In the south the volcanic province is somewhat narrow and crosses diagonally through the northwesterly structural trend of the Coast Mountains.<ref name="SLV"/> Farther north it is less clearly defined, forming a large arch that swings westward through central Yukon.<ref name="SLV"/> Volcanoes within the British Columbia portion of the Northern Cordilleran Volcanic Province are disposed along short, northerly trending en-echelon segments which, in the British Columbia portion of the volcanic province, are unmistakably involved with north-trending rift structures including synvolcanic grabens and half-grabens similar to the East African Rift, which extends from the Afar triple junction southward across eastern Africa.<ref name="SLV"/> The Northern Cordilleran rift system formed as a result of the North American continent being stretched by extensional forces as the Pacific Plate slides northward along the Queen Charlotte Fault to the west, on its way to the Aleutian Trench, which extends along the southern coastline of Alaska and the adjacent waters of northeastern Siberia off the coast of Kamchatka Peninsula.<ref name="ZAM"/> As the continental crust stretches, the near-surface rocks fracture along steeply dipping cracks parallel to the rift known as faults. Hot basaltic magma rises along these fractures to create passive lava eruptions. The compositions of lavas in the Northern Cordilleran Volcanic Province are mantle-derived alkali olivine basalt, lesser hawaiite and basanite, which form the large shield volcanoes and small cinder cones throughout the volcanic province.<ref name="SLV"/> Many of them contain inclusions of lherzolite.<ref name="SLV"/> The large central volcanoes of the volcanic province consist largely of trachyte, pantellerite, and comendite lavas.<ref name="SLV"/> These lava compositions were formed by fractionation of primary alkali basalt magma in crustal reservoirs.<ref name="SLV"/> A region of continental rifting, such as the Northern Cordilleran Volcanic Province, would support the development of high-level reservoirs of sufficient size and thermal capacity to sustain prolonged fractionation.<ref name="SLV"/>
thumb|left|Map of the Anahim Volcanic Belt The Anahim Volcanic Belt extends from coastal British Columbia across the Coast Mountains into the Interior Plateau.<ref name="SLV"/> Its western end is defined by alkaline intrusive and comagmatic volcanic rocks of the Bella Bella-King Island complex, exposed in fjords and islands of the western Coast Mountains.<ref name="SLV"/> The central portion of the Anahim Volcanic Belt contains three complex shield volcanoes, known as the Rainbow, Ilgachuz, and Itcha ranges.<ref name="SLV"/> These fairly dissected shield volcanoes lie on the northern end of the Chilcotin Group lava plateau and distal lava flows at the margins of the shield volcanoes merge imperceptibly with flat-lying lava flows comprising the Chilcotin Group lava plateau.<ref name="SLV"/> Unlike the Chilcotin Group basalt, which is not associated with any felsic derivatives, the volcanoes of the central Anahim Volcanic Belt are markedly bimodal, comprising a mixed assemblage of basalt and peralkaline silicic rocks.<ref name="SLV"/> While volcanoes of the Anahim Volcanic Belt appear to merge laterally with the Chilcotin Group lavas, the particular nature and connection between the Anahim Volcanic Belt and the Chilcotin Group is unknown.<ref name="SLV"/> However, volcanoes within the Anahim Volcanic Belt usually become younger from coastal British Columbia to near the small city of Quesnel further east, indicating these volcanoes may have formed as a result of the North American Plate passing over a possible mantle plume known as the Anahim hotspot, whereas the Chilcotin Group is related to back-arc basin volcanism.<ref>{{cite web|title=Anahim volcanic belt |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=February 13, 2008 |url=http://cgc.rncan.gc.ca/volcanoes/cat/belt_anahim_e.php |access-date=February 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20070311030816/http://cgc.rncan.gc.ca/volcanoes/cat/belt_anahim_e.php |archive-date=March 11, 2007 }}</ref> Nazko Cone, a cluster of basaltic cinder cones in the Nazko area {{convert|75|km}} west of Quesnel forms the youngest and most easterly part of the Anahim Volcanic Belt with dates of 7,200 years.<ref name="SLV"/>
thumb|right|Pillow lavas and breccia overlain with slabby pieces of sulfide formed from hydrothermal venting on the east side of the Southern Explorer Ridge. The Explorer Ridge, an underwater mountain range lying {{convert|160|km}} west of Vancouver Island on the Coast of British Columbia, consists of a north-south trending rift zone.<ref name="ZOH">{{cite web|publisher=NOAA |url=http://oceanexplorer.noaa.gov/%E2%80%8Cexplorations/02fire/logs/yr_sum/yr_sum.html |archive-url=https://archive.today/20110926235701/http://oceanexplorer.noaa.gov/%E2%80%8Cexplorations/02fire/logs/yr_sum/yr_sum.html |url-status=dead |archive-date=September 26, 2011 |title=Submarine Ring of Fire - Summary of Year One at Explorer Ridge |date=July 11, 2002 |access-date=February 19, 2009 }}</ref> It contains one major segment known as the Southern Explorer Ridge, along with other smaller segments, such as the Northern Explorer Ridge.<ref name="AAI">{{cite web|publisher=NOAA|url=http://oceanexplorer.noaa.gov/explorations/02fire/background/plan/plan.html|title=Mission Plan - Explorer Ridge, 2002|year=2002|access-date=February 19, 2009}}</ref> With a depth of {{convert|1800|m}}, the Southern Explorer Ridge is relatively shallow in comparison with most other rift zones of the northeast Pacific Ocean, indicating there has been considerable volcanic activity along this part of the Explorer Ridge in the past 100,000 years.<ref name="AAI"/> Magic Mountain, a large hydrothermal vent area on the Southern Explorer Ridge, is a scene of this volcanic activity.<ref name="AAI"/> Unlike most hydrothermal systems found in the Pacific Ocean, the Magic Mountain site is situated outside the primary rift zone.<ref name="ZOH"/> The source for the hydrothermal fluid that fuels Magic Mountain probably rises along fracture systems associated with a recent episode of rifting that, in turn, followed a massive outpouring of lava.<ref name="ZOH"/> In contrast, the Northern Explorer Ridge has evolved into a complex compound structure consisting of several rift basins bounded by half-graben and arcuate shaped faults with a superimposed pattern of rhombohedral grabens and horsts.
thumb|left|This vigorously venting black smoker of the Main Endeavor hydrothermal field, called Sully, emits jets of particle-laden fluids that create the black smoke. The Endeavor Segment, an active rift zone of the larger Juan de Fuca Ridge on the British Columbia Coast, contains a group of active black smokers called the Endeavor Hydrothermal Vents, located {{convert|250|km}} southwest of Vancouver Island.<ref name="ZIO">{{cite web|publisher=Fisheries and Oceans Canada|url=http://www.dfo-mpo.gc.ca/oceans/marineareas-zonesmarines/mpa-zpm/pacific-pacifique/factsheets-feuillets/endeavour-eng.htm|title=Endeavour Hydrothermal Vents|work=Marine Protected Area|date=March 31, 2008|access-date=January 12, 2009}}</ref> This group of hydrothermal vents lies {{convert|2250|m}} below sea level and consists of five hydrothermal fields, known as ''Sasquatch'', ''Saily Dawg'', ''High Rise'', ''Mothra'', and ''Main Endeavor''.<ref name="ZIO"/> Like typical hydrothermal vents, the Endeavor Hydrothermal Vents form when cold seawater seeps into cracks and crevices in the Endeavor Segment where it becomes heated by magma that lies beneath the seafloor. As the water is heated, it rises and seeks a path back out into the Pacific Ocean through openings in the Endeavor Segment, forming hydrothermal vents. These hydrothermal vents release fluids with temperatures of over 300 °C and have been a focus of research by Canadian and international scientists.<ref name="ZIO"/> The crewed United States Navy deep-ocean research submersible DSV Alvin and the remotely operated underwater vehicle Jason have done work at the Endeavor Hydrothermal Vents.<ref name="ZIO"/> Joint Canada-United States studies have made use of the Canadian Remotely Operated Platform for Ocean Sciences.<ref name="ZIO"/> Fisheries and Oceans Canada has conducted extensive acoustic and mooredinstrument programs at the Endeavor Hydrothermal Vents since 1985.<ref name="ZIO"/>
== Northern Canada == {{Main|Volcanism of Northern Canada}} thumb|right|Map of the 1,267-million-year-old Mackenzie dike swarm (black lines). Dots indicate areas where flow direction was determined. Red arcuate line indicates boundary between vertical flow and horizontal flow. Vast volumes of basaltic lava covered Northern Canada in the form of a flood basalt event 1,267 million years ago that engulfed the landscape near the Coppermine River southwest of Coronation Gulf in the Canadian Arctic.<ref name="QIE">{{cite book|last=Lambert|first=Maurice B.|title=Volcanoes|year=1978|publisher=Energy, Mines and Resources Canada|location=North Vancouver, British Columbia|isbn=978-0-88894-227-2|url-access=registration|url=https://archive.org/details/volcanoes0000lamb}}</ref> This volcanic activity built an extensive lava plateau and large igneous province with an area of {{convert|170000|km2|sqmi|0|abbr=on}} representing a volume of lavas of at least {{convert|500000|km3|cumi|0|abbr=on}}.<ref name="QIE"/> With an area of {{convert|170000|km2|sqmi|0|abbr=on}} and a volume of at least {{convert|500000|km3|cumi|0|abbr=on}}, it is larger than the Columbia River Basalt Group in the United States and comparable in size to the Deccan Traps in west-central India, making it one of the largest flood basalt events ever to appear on the North American continent, as well as on Earth. This massive eruptive event was associated with the Mackenzie magmatic event, that included the coeval, layered, mafic-ultramafic Muskox intrusion and the enormous Mackenzie dike swarm that diverges from the Coppermine River flood basalts.<ref name="ON">{{cite book|last1=Yoshida|first1=M.|last2=B. F. Windley|first2= S. Dasgupta|title=Proterozoic East Gondwana: Supercontinent Assembly and Breakup|publisher=The Geological Society|date= 2003|page=26|url=https://books.google.com/books?id=4B8nrDVjaCgC&pg=PA26|isbn=978-1-86239-125-3}}</ref> The maximum thickness of the flood basalts are {{convert|4.7|km|mi|0|abbr=on}} and consist of 150 lava flows, each {{convert|4|to|100|m|ft|0|abbr=on}} thick.<ref name="ON"/> These flood basalt lava flows were erupted during a single event that lasted less than five million years.<ref name="ON"/> Analysis of the chemical composition of the lavas gives important clues about the origin and dynamics of the flood basalt volcanism.<ref name="ON"/> The lowermost lavas were produced by melting in the garnet stability field below the surface at a depth of more than {{convert|90|km}} in a mantle plume environment beneath the North American lithosphere.<ref name="ON"/> As the mantle plume intruded rocks of the Canadian Shield, it created an upwelling zone of molten rock known as the Mackenzie hotspot. Upper lavas were partly contaminated with crustal rocks as magmas from the mantle plume passed through the lower and upper crust.<ref name="ON"/>
During the Early Jurassic period 196 million years ago, the New England or Great Meteor hotspot existed in the Rankin Inlet area of southern Nunavut along the northwestern coast of Hudson Bay, producing kimberlite magmas.<ref name="ZP">{{cite book|last=Condie|first=Kent C.|title=Mantle Plumes and Their Record in Earth History|publisher=Cambridge University Press|year=2001|page=21|url=https://books.google.com/books?id=eMIXrEXORWkC&pg=PA21|isbn=978-0-521-01472-4}}</ref> This marks the first appearance of the New England hotspot, as well as the oldest kimberlite eruption throughout the New England or Great Meteor hotspot track, which extends southeastwards across Canada and enters the northern Atlantic Ocean where the New England hotspot is located.<ref name="ZP"/>
[[File:Dragon Cliffs, Nunavut.jpg|thumb|left|Dragon Cliff on western Axel Heiberg Island is made of flood basalt lava flows of the Strand Fiord Formation]] The Sverdrup Basin Magmatic Province of northern Nunavut forms a large igneous province 95 to 92 million years old in the Canadian Arctic.<ref name="ZZK">{{Cite web |url=http://meguma.earthsciences.dal.ca/zentilli_PPT/Zentilli_Abstract-004.pdf |title=Archived copy |access-date=2009-03-03 |archive-date=2011-08-21 |archive-url=https://web.archive.org/web/20110821172923/http://meguma.earthsciences.dal.ca/zentilli_PPT/Zentilli_Abstract-004.pdf |url-status=dead }}</ref> Part of the larger High Arctic Large Igneous Province, it consists of two volcanic formations called the Ellesmere Island Volcanics and Strand Fiord Formation. In the Strand Fiord Formation, flood basalt lavas reach a thickness of at least {{convert|1|km|ft}}.<ref name="ZZK"/> Flood basalts of the Sverdrup Basin Magmatic Province are similar to terrestrial flood basalts associated with breakup of continents, indicating the Sverdrup Basin Magmatic Province formed as a result of rifting of the Arctic Ocean and when the large underwater Alpha Ridge was still geologically active.<ref name="ZZK"/>
Widespread basalt volcanism occurred between 60.9 and 61.3 million years ago in the northern Labrador Sea, Davis Strait and in southern Baffin Bay on the eastern coast of Nunavut during the Paleocene period when North America and Greenland were being separated from tectonic movements. This resulted from seafloor spreading where new ocean seafloor was being created from rising magma. Scientific studies have indicated nearly 80% of the magma was erupted in one million years or less.<ref name="ID">{{cite journal|title= 40Ar/39Ar geochronology of the West Greenland Tertiary volcanic province |date=1998|doi=10.1016/S0012-821X(98)00112-5 |bibcode=1998E&PSL.160..569S |volume=160 |issue= 3–4 |journal=Earth and Planetary Science Letters |pages=569–586|last1= Storey |first1= M |last2= Duncan |first2= R.A |last3= Pedersen |first3= A.K |last4= Larsen |first4= L.M |last5= Larsen |first5= H.C }}</ref> The source for this volcanic activity was the Iceland plume along with its surface expression, the Iceland hotspot.<ref name="ID"/> This volcanic activity formed part of a large igneous province that is sunken beneath the northern Labrador Sea.<ref name="ID"/> Another period of volcanic activity began in the same region about 55 million years ago during the Eocene period when the north-south trending Mid-Atlantic Ridge began to form under the northern Atlantic Ocean east of Greenland. The cause of this volcanism might be related to partial melting from movement of a transform fault system extending from Labrador Sea to the south and Baffin Bay to the north.<ref name="ID"/> Although the region was carried away from the Iceland plume by going plate motion over millions of years, the source of the partial melting for the final period of volcanic activity may have been remnants of still anomalously hot Iceland plume magma which were left stranded beneath the North American lithosphere in the Paleocene period.<ref name="ID"/> Most diatremes in the Northwest Territories were formed by volcanic eruptions between 45 and 75 million years ago during the Eocene and Late Cretaceous periods.
More recent volcanic activity has created a northwest trending line of volcanic rocks called the Wrangell Volcanic Belt.<ref name="SLV"/> This volcanic belt lies largely in the U.S. state of Alaska, but extends across the Alaska-Yukon border into southwestern Yukon where it contains scattered remnants of subaerial lavas and pyroclastic rocks which are preserved along the entire eastern fringe of the ice covered Saint Elias Mountains.<ref name="SLV"/> The Wrangell Volcanic Belt formed as a result of arc volcanism related to subduction of the Pacific Plate under the northern portion of the North American Plate.<ref name="SLV"/> Over large areas extrusive rocks lie in flat undisturbed piles on a Tertiary surface of moderate relief.<ref name="SLV"/> Locally, however, strata of the same age have been affected by a late pulse of tectonism, during which they were faulted, contorted into tight symmetrical folds, or overridden by pre-Tertiary basement rocks along southwesterly dipping thrust faults.<ref name="SLV"/> Considerable recent uplift, accompanied by rapid erosion, has reduced once vast areas of upper Tertiary volcanic rocks to small isolated remnants.<ref name="SLV"/> Although no eruptions have occurred in the Yukon portion of the Wrangell Belt for the past five million years, two large (VEI-6) explosive eruptions from Mount Churchill {{convert|24|km}} west of the Alaska-Yukon border, created the White River Ash deposit.<ref name="SSS">{{cite web | title = Mount Churchill | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=wvb_usa_003 | access-date = February 19, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20090608030118/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=wvb_usa_003 | archive-date = June 8, 2009 }}</ref> This volcanic ash deposit is estimated 1,890 and 1,250 years old, covering more than {{convert|340000|km2|sqmi|abbr=on}} of northwestern Canada and adjacent eastern Alaska.<ref name="SSS"/> Native American legends about the area indicate the final eruption from Mount Churchill 1,250 years ago disrupted food supplies and forced them to move further south.<ref name="SSS"/>
The Yukon portion of the northwest trending Northern Cordilleran Volcanic Province includes the youngest volcanoes in Northern Canada. The Fort Selkirk Volcanic Field in central Yukon consists of valley-filling basalt lava flows and cinder cones.<ref name="QQJ" /> Ne Ch'e Ddhawa, a cinder cone {{convert|2|km}} away from the connection of the Yukon and Pelly rivers formed between 0.8 and one million years ago when this area lied beneath the vast Cordilleran Ice Sheet.<ref>{{cite web | title = IPY GeoNorth 2007 | work = Northern Landscapes | publisher = Natural Resources Canada | date = April 25, 2007 | url = http://ess-sst.nrcan-rncan.gc.ca/ipygeonorth/land_e.php | access-date = January 24, 2009}} {{Dead link|date=September 2010|bot=H3llBot}}</ref> The youngest volcano, Volcano Mountain just north of the junction of the Yukon and Pelly rivers, formed in past 10,000 years (Holocene), producing lava flows that remain unvegetated and appear to be only a few hundred years old. However, dating of sediments in a lake impounded by the lava flows indicated that the youngest lava flows could not be younger than mid-Holocene and could be early Holocene or older. Therefore, the most recent activity in the Fort Selkirk volcanic field is unknown.<ref name="QQJ"/> The lava flows from Volcano Mountain are unusual because they originate much deeper in the Earth's mantle than the more common basaltic lava flows found throughout the Yukon and are very uncommon in the geological record.<ref name="CIM">{{cite web|title=Stikine volcanic belt: Volcano Mountain |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=February 13, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_volcano_e.php |access-date=January 24, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090307140121/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_volcano_e.php |archive-date=March 7, 2009 }}</ref> This lava, known as olivine nephelinite, is also unusual because it contains small, angular to rounded fragments of rock called nodules.<ref name="CIM"/>
== Economic geology ==
=== Greenstone belts === [[File:Kidd Mine.jpg|thumb|right|Volcanogentic massive sulfide ore deposit at Kidd Mine, Timmins, Ontario, Canada, formed 2.4 billion years ago on an ancient seafloor.]] The predominantly volcanic Archean and Proterozoic greenstone belts throughout Canada are important for estimating Canada's mineral potential.<ref name="QIE"/> Consequently, geologists study greenstone belts to understand the volcanoes and the environment in which they erupted, and to provide a working model for mineral exploration.<ref name="QIE"/> The 1,904‑ to 1,864‑million-year-old Flin Flon greenstone belt of central Manitoba and east-central Saskatchewan is one of the largest Paleoproterozoic age volcanogenic massive sulfide ore deposits in the world, containing 27 copper-zinc-(gold) deposits from which more than 183 million tonnes of sulfide ore have been mined.<ref name=Norris>{{cite web |author=Norris, Jessica |title=Report on the 2007 Diamond Drilling Program McClarty Lake Project, Manitoba |publisher=Aurora Geosciences Ltd. |year=2007 |url=http://www.troymet.com/i/pdf/2007McClarty43-101.pdf |access-date=February 22, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080530010956/http://www.troymet.com/i/pdf/2007McClarty43-101.pdf |archive-date=May 30, 2008 }}</ref> The 2,575‑million-year-old Yellowknife greenstone belt in the Northwest Territories is the host for world-class gold deposits with total production of 15 million ounces of gold.<ref>{{cite journal |last1=Ootes |first1=L. |last2=Lentz |first2=D. R. |last3=Creaser |first3=R. A. |last4=Ketchum |first4=J. W. F. |last5=Falck |first5=H. |title=Re-Os MOLYBDENITE AGES FROM THE ARCHEAN YELLOWKNIFE GREENSTONE BELT: COMPARISON TO U-Pb AGES AND EVIDENCE FOR METAL INTRODUCTION AT 2675 Ma |journal=Economic Geology |date=1 May 2007 |volume=102 |issue=3 |pages=511–518 |doi=10.2113/gsecongeo.102.3.511 |bibcode=2007EcGeo.102..511O }}</ref> In the Archean Hope Bay greenstone belt of western Nunavut, three large gold deposits have been known as Doris, Boston and Madrid,<ref>{{cite web|url=http://www.portergeo.com.au/database/mineinfo.asp?mineid=mn1220 |title=Porter GeoConsultancy - Ore Deposit Description |publisher=Portergeo.com.au |access-date=June 30, 2010}}</ref> while the 2,677‑million-year-old Abitibi greenstone belt of Ontario and Quebec is the second most prolific gold producing area on Earth; the most prolific gold producing area is the Witwatersrand hill range in South Africa.<ref>{{cite web|url=http://www.dentonia.net/_resources/news/news-2006-02-13.pdf |title=Archived copy |access-date=March 3, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20080819185731/http://www.dentonia.net/_resources/news/news-2006-02-13.pdf |archive-date=August 19, 2008 }}</ref>
thumb|left|Map of the 2,500- to 2,450-million-year-old Matachewan dike swarm and the 2,500-million-year-old Mistassini dike swarm of eastern Canada
=== Intrusions === Other magmatic formations, such as dike swarms and sills, are known to contain base and precious metal deposits. The 2,500- to 2,450-million-year-old Matachewan dike swarm of eastern Ontario hosts the 2,491- to 2,475-million-year-old {{convert|20|km}} long East Bull Lake Intrusion and associated intrusions.<ref name="GHE">{{cite web|title=Regional Metallogeny Large Igneous Provinces in Canada Through Time and Their Metallogenic Potential |work=Mineral Deposits of Canada |publisher=Geological Survey of Canada |date=September 25, 2008 |url=http://gsc.nrcan.gc.ca/mindep/synth_prov/lip/index_e.php |access-date=January 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20100420110929/http://gsc.nrcan.gc.ca/mindep/synth_prov/lip/index_e.php |archive-date=April 20, 2010 }}</ref> The 2,217- to 2,210-million-year-old Ungava magmatic event was the source for the Nipissing sills of Ontario and have been historically important for copper, silver, and arsenic mineralization, and also have the potential to contain platinum group metals.<ref name="GHE"/> A third major event is the 1,885‑ to 1,865‑million-year-old magmatism of the Circum-Superior Belt surrounding much of the Superior craton from the Labrador Trough in Labrador and northeastern Quebec, though the Cape Smith Belt in northern Quebec, the Belcher Islands in southern Nunavut, the Fox River and Thompson belts in northern Manitoba, the Winnipegosis komatiite belt in central Manitoba, and on the southern side of the Superior craton in the Animikie Basin of northwestern Ontario.<ref name="GHE"/> Included within the Circum-Superior large igneous province are major nickel deposits of the Thompson and Raglan belts, which were likely derived from more than one magma source.<ref name="GHE"/> The major 1,267‑million-year-old Mackenzie dike swarm magmatism in the western part of the Canadian Shield is the host for the highly prospected Muskox intrusion.<ref name="GHE"/> Another significant event was the magmatism that formed the 723‑million-year-old Franklin dike swarm of Northern Canada and has been heavily mined for nickel, copper, and platinum group metals.<ref name="GHE"/> The 230‑million-year-old accreted oceanic plateau, Wrangellia in British Columbia and Yukon, has also been searched for nickel, copper, and platinum group metals.<ref name="GHE"/>
=== Diatremes === thumb|right|Diavik Diamond Mine in the Northwest Territories consists of three diatremes The kimberlite diatremes, or pipes, across Canada have also been important economically, because kimberlite magmas are the world's main source of gem-quality diamonds.<ref name="SLO">{{cite web|title=Types of volcanoes |work=Volcanoes of Canada |publisher=Geological Survey of Canada |date=February 25, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/type_e.php |access-date=January 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090202064852/http://gsc.nrcan.gc.ca/volcanoes/type_e.php |archive-date=February 2, 2009 }}</ref> Kimberlite pipes form when kimberlite magmas rise considerably from depths as great as {{convert|400|km}}.<ref name="ZKY">{{cite web|publisher=Stephen Forgacs|url=http://www.publicaffairs.ubc.ca/ubcreports/1997/97oct16/diamond.html|title=Diamond researchers first to publish findings|date=October 16, 1997|access-date=April 19, 2009|archive-date=March 26, 2010|archive-url=https://web.archive.org/web/20100326011015/http://www.publicaffairs.ubc.ca/ubcreports/1997/97oct16/diamond.html|url-status=dead}}</ref> As the kimberlite magmas approach a depth of at least {{convert|2|km}}, the magma explodes violently through the Earth's crust, carrying fragments of rock that it has collected along the way and, in the right conditions, possibly diamonds, to the surface.<ref name="ZKY"/> The Eocene (ca. 55–50 Ma) age diatremes of the Lac de Gras kimberlite field in the central Slave craton of the Northwest Territories support two world-class diamond mines, called Ekati and Diavik.<ref>{{cite web|url=http://www.northarrowminerals.com/s/LacdeGras.asp |title=North Arrow Minerals Inc. - Lac de Gras - Tue June 29, 2010 |publisher=Northarrowminerals.com |date=February 24, 2010 |access-date=June 30, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100609110127/http://www.northarrowminerals.com/s/LacdeGras.asp |archive-date=June 9, 2010 }}</ref> Ekati, Canada's first diamond mine,<ref name="northern star"/> has produced {{convert|40000000|carat|kg}} of diamonds out of six open pits between 1998 and 2008,<ref name="northern star">{{cite journal| last = Zlotnikoc| first = Dan|date=November 2008| title = A northern star - Canada's first diamond mine celebrates a milestone| journal = CIM Magazine| volume = 3| issue = 7| pages = 40–43| location = Montreal, Quebec, Canada| issn = 1718-4177}}</ref> while Diavik, to the southeast, has produced {{convert|35400000|carat|kg}} of diamonds since its foundation in 2003.<ref>{{cite news | title = Diavik diamond mine in N.W.T gets new development money | publisher = CBC News | url = https://www.cbc.ca/news/business/diavik-diamond-mine-in-n-w-t-gets-new-development-money-1.668146 |access-date = January 25, 2009 | date=November 26, 2007}}</ref> The diamondiferous Drybones Bay kimberlite pipe is the largest diatreme discovered in the Northwest Territories, measuring {{convert|900|x|400|m|ft}}.<ref>{{cite journal |last1=Power |first1=M. A |title=A seismic signature of the Drybones Bay kimberlite pipe, N.W.T |journal=CIM Bulletin |date=1998 |volume=91 |issue=1017 |pages=66–69 |id={{INIST|2269136}} }}</ref> Diamondiferous diatremes throughout the Northwest Territories and Alberta have the potential to make Canada one of the world's major producers of gem-quality diamonds.<ref name="SLO"/>
== Recent activity == {{Main|Volcanology of Western Canada|Volcanology of Northern Canada}} Canada continues to be volcanically active, but the dispersed population has witnessed few eruptions due to the remoteness of the volcanoes and their low level of activity.<ref name="AKB">{{cite journal |last1=Stasiuk |first1=Mark V |last2=Hickson |first2=Catherine J. |author-link2=Catherine Hickson |last3=Mulder |first3=Taimi |title=The vulnerability of Canada to volcanic hazards |journal=Natural Hazards |location=Dordrecht |date=2003 |volume=28 |issue=2–3 |pages=563–589 |id={{INIST|14897949}} |doi=10.1023/A:1022954829974 |bibcode=2003NatHa..28..563S |s2cid=129461798 }}</ref> The span of recorded and witnessed volcanic activity in Canada differs from region to region and at least two eruptions have been witnessed by people.<ref>{{cite web|title=Map of Canadian volcanoes |work=Volcanoes of Canada |publisher=Geological Survey of Canada |date=February 13, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/map/index_e.php |access-date=March 1, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20080602043532/http://gsc.nrcan.gc.ca/volcanoes/map/index_e.php |archive-date=June 2, 2008 }}</ref> Part of the Pacific Ring of Fire, more than 200 potentially active volcanoes exist throughout Canada, 49 of which have erupted in the past 10,000 years (Holocene).<ref name="AKB"/> This is very recent in geological terms, suggesting volcanoes in Canada have ongoing activity.<ref name="HEPO"/> Ongoing scientific studies have indicated there have been earthquakes associated with at least ten Canadian volcanoes, including: Mount Garibaldi,<ref name="UY"/> Hoodoo Mountain,<ref name="UY"/> Castle Rock,<ref name="UY"/> Mount Cayley,<ref name="UY"/> The Volcano,<ref name="UY"/> Crow Lagoon,<ref name="UY"/> Silverthrone Caldera,<ref name="UY"/> Mount Meager massif,<ref name="UY"/> the Wells Gray-Clearwater volcanic field,<ref name="UY"/> and the Mount Edziza volcanic complex.<ref name="UY"/>
thumb|right|Keyhole Falls - all that grey is ash from the last time Mount Meager erupted 2,350 years ago [[File:Meager hot spring.jpg|thumb|right|A volcanic hot spring pool near Meager Creek related to volcanism of the Mount Meager massif]] The Mount Meager massif in the Garibaldi Volcanic Belt of southwestern British Columbia was the source for a massive (VEI-5) Plinian eruption 2,350 years ago similar in character to the 1980 eruption of Mount St. Helens in the U.S. state of Washington.<ref name="IK"/><ref name="ALO"/> The eruption originated from a vent on the northeast flank of Plinth Peak, the highest and one of four overlapping stratovolcanoes which together form the Mount Meager massif.<ref name="GPQ">{{cite gvp|vn=320180|title=Meager|access-date=January 21, 2009}}</ref> This activity produced a diverse sequence of volcanic deposits, well exposed in bluffs along the {{convert|209|km}} long Lillooet River, which are grouped as part of the Pebble Creek Formation.<ref name="ZJR"/> The explosive power associated with this Plinian eruption sent an ash column estimated to have risen at least {{convert|20|km}} above Meager, indicating it entered the second major layer of the Earth's atmosphere.<ref name="ALO">{{cite web|title=Garabaldi volcano belt: Mount Meager volcanic field |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=February 13, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_meager_e.php |access-date=January 21, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110604145927/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_meager_e.php |archive-date=June 4, 2011 }}</ref> As prevailing winds sent ash and dust as far as {{convert|530|km}} to the east, it created the large Bridge River Ash deposit, extending from Mount Meager to central Alberta.<ref name="ALO"/><ref>{{cite web|title=Distribution of tephra deposits in Western North America |work=Volcanoes of Canada |publisher=Geological Survey of Canada |date=February 12, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/fig08_e.php |access-date=January 21, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110604153752/http://gsc.nrcan.gc.ca/volcanoes/fig08_e.php |archive-date=June 4, 2011 }}</ref> Pyroclastic flows travelled {{convert|7|km|0}} downstream from the vent and buried trees along Meager's forested slopes, which were burned in place.<ref name="ALO"/><ref>{{cite web|last=Edwards |first=Ben |title=Mt. Meager, SW British Columbia, Canada |work=VolcanoWorld |date=November 2000 |url=http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/canada/Final-Meager.html |access-date=January 21, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20120216070904/http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/canada/Final-Meager.html |archive-date=February 16, 2012 }}</ref> An unusual, thick apron of welded vitrophyric breccia may represent the explosive collapse of a former lava dome which deposited ash several meters in thickness near the vent area.<ref name="ALO"/><ref name="ZJR"/> This collapse blocked the Lillooet River to a height of at least {{convert|100|m}}, forming a lake.<ref name="ZJR">{{cite journal |last1=Hickson |first1=C. J. |last2=Russell |first2=J. K. |last3=Stasiuk |first3=M. V. |title=Volcanology of the 2350 B.P. Eruption of Mount Meager Volcanic Complex, British Columbia, Canada: implications for Hazards from Eruptions in Topographically Complex Terrain |journal=Bulletin of Volcanology |date=12 April 1999 |volume=60 |issue=7 |pages=489–507 |doi=10.1007/s004450050247 |bibcode=1999BVol...60..489H |s2cid=53421677 }}</ref> The lake reached a maximum elevation of {{convert|810|m}} and thus was at least {{convert|50|m}} deep.<ref name="ZJR"/> The pyroclastic deposits blocking the Lillooet River eventually eroded from water activity, causing a massive outburst flood that sent small house-sized boulders down the Lillooet River valley, and formed {{convert|23|m}} high Keyhole Falls.<ref name="ALO"/> The final phase of activity produced a {{convert|2|km}} long glassy dacite lava flow that varies from {{convert|15|to|20|m|ft|abbr=on}} thick. This is the largest known explosive eruption in Canada in the past 10,000 years.<ref name="GPQ"/> Two clusters of hot springs are found at the Mount Meager massif, suggesting magmatic heat is still present and volcanic activity continues.<ref name="GPQ"/>
thumb|left|South side of Cocoa Crater The massive Mount Edziza volcanic complex in the Northern Cordilleran Volcanic Province of northern British Columbia has had more than 20 eruptions throughout the past 10,000 years (Holocene), including Mess Lake Cone,<ref>{{cite web|title=Mess Lake |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_msl_097 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20101211101239/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_msl_097 |archive-date=December 11, 2010 }}</ref> Kana Cone,<ref>{{cite web|title=Kana Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_kcn_011 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20071110044017/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_kcn_011 |archive-date=November 10, 2007 }}</ref> Cinder Cliff,<ref>{{cite web|title=Cinder Cliff |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ccl_073 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110719225429/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ccl_073 |archive-date=July 19, 2011 }}</ref> Icefall Cone,<ref>{{cite web|title=Icefall Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ifc_034 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20101211101116/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ifc_034 |archive-date=December 11, 2010 }}</ref> Ridge Cone,<ref>{{cite web|title=Ridge Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_rcn_035 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20101211101401/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_rcn_035 |archive-date=December 11, 2010 }}</ref> Williams Cone,<ref>{{cite web|title=Williams Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_mic_018 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110604180302/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_mic_018 |archive-date=June 4, 2011 }}</ref> Walkout Creek Cone,<ref>{{cite web | title = Walkout Creek | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_wcr_092 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20101212061045/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_wcr_092 | archive-date = December 12, 2010 }}</ref> Moraine Cone,<ref>{{cite web | title = Moraine Cone | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_moc_012 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20071112095708/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_moc_012 | archive-date = November 12, 2007 }}</ref> Sidas Cone,<ref>{{cite web|title=Sidas Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_sic_013 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20071112095719/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_sic_013 |archive-date=November 12, 2007 }}</ref> Sleet Cone,<ref>{{cite web | title = Sleet Cone | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_sic_014 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20071112095724/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_sic_014 | archive-date = November 12, 2007 }}</ref> Storm Cone,<ref>{{cite web | title = Storm Cone | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_stc_015 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20071111155130/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_stc_015 | archive-date = November 11, 2007 }}</ref> Triplex Cones,<ref>{{cite web | title = Triplex Cone | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_trc_016 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20071110044042/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_trc_016 | archive-date = November 10, 2007 }}</ref> Twin Cone,<ref>{{cite web|title=Twin Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_twc_017 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20071112095734/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_twc_017 |archive-date=November 12, 2007 }}</ref> Cache Hill,<ref>{{cite web|title=Cache Hill |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_cah_036 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110604164829/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_cah_036 |archive-date=June 4, 2011 }}</ref> Camp Hill,<ref>{{cite web|title=Camp Hill |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_cah_037 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110604170115/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_cah_037 |archive-date=June 4, 2011 }}</ref> Cocoa Crater,<ref>{{cite web | title = Cocoa Cone | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ccn_088 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20101212060930/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ccn_088 | archive-date = December 12, 2010 }}</ref> Coffee Crater,<ref>{{cite web | title = Coffee Crater | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ccr_089 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20101211081030/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ccr_089 | archive-date = December 11, 2010 }}</ref> Nahta Cone,<ref>{{cite web|title=Nahta Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ncn_095 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20101211093755/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_ncn_095 |archive-date=December 11, 2010 }}</ref> Tennena Cone,<ref>{{cite web | title = Tennena Cone | work = Catalogue of Canadian volcanoes | publisher = Geological Survey of Canada | date = August 19, 2005 | url = http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tcn_094 | access-date = January 22, 2009 | url-status = dead | archive-url = https://web.archive.org/web/20101211101432/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tcn_094 | archive-date = December 11, 2010 }}</ref> The Saucer,<ref>{{cite web|title=The Saucer |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tsu_091 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20101211102020/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tsu_091 |archive-date=December 11, 2010 }}</ref> and the well-preserved Eve Cone.<ref name="ACO"/><ref>{{cite web|title=Eve Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_evc_010 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20071112010028/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_evc_010 |archive-date=November 12, 2007 }}</ref> Active or recently active hot springs are found in several areas along the western flank of Edziza's lava plateau, including Elwyn springs (36 °C), Taweh springs (46 °C), and inactive springs near Mess Lake.<ref name="ACO"/> All three hydrothermal areas are near the youngest lava fields on the lava plateau and are probably associated with the most recent volcanic activity at the Mount Edziza volcanic complex.<ref name="ACO"/> An undated pumice deposit exists throughout the complex estimated to be younger than 500 years.<ref>{{cite journal |last1=Yagi |first1=Kenzo |last2=Souther |first2=Jack Gordon |title=Aenigmatite from Mt. Edziza, British Columbia, Canada |journal=American Mineralogist |date=1 August 1974 |volume=59 |issue=7–8 |pages=820–829 |url=https://pubs.geoscienceworld.org/msa/ammin/article-abstract/59/7-8/820/541110 }}</ref>
thumb|right|Kostal Cone in the Wells Gray-Clearwater volcanic field Kostal Cone in the Wells Gray-Clearwater volcanic field of east-central British Columbia is a cinder cone responsible for basaltic lava flows comprising a lava bed, damming the southern end of McDougall Lake.<ref>{{cite web |url=http://ralphbudgell.tripod.com/files/murtle_brochure.pdf |title=Murtle Lake Marine Guide, Wells Gray Provincial Park |publisher=BC Parks, Ministry of Water, Land and Air Protection |access-date=5 October 2023}}</ref> There has been activity at this site as recently as 7,600 years ago at Dragon Cone, though more likely less than 1,000 years ago. Kostal Cone is too young for the potassium-argon dating technique (usable on specimens over 100,000 years old), and no charred organic material for radiocarbon dating has been found. However, the uneroded structure of the cone with the existence of trees on its flanks and summit have made it an area for dendrochronology studies, which reveals the growth of tree-ring patterns.<ref name="ZOI">{{cite gvp|vn=320150|vtab=Eruptions|title=Wells Gray-Clearwater: Eruptive History|access-date=January 23, 2009}}</ref> Tree-ring dating has revealed an age of about 400 years for Kostal Cone, indicating it formed around 1500.<ref name="ZOI"/><ref name="JPT">{{cite gvp|vn=320150|title=Wells Gray-Clearwater|access-date=January 23, 2009}}</ref> This makes Kostal Cone the youngest volcano in the Wells Gray-Clearwater volcanic field and thus one of the youngest in Canada.<ref name="JPT"/>
thumb|left|Nass valley lava beds erupted from Tseax Cone in 1750 or 1775 Tseax Cone, a young cinder cone at the southernmost end of the Northern Cordilleran Volcanic Province, was the source for a major basalt lava flow eruption around the years 1750 and 1775 that travelled into the Tseax River, damming it and forming Lava Lake.<ref name="AU">{{cite gvp|vn=320100|title=Tseax River Cone|access-date=January 19, 2009}}</ref> The lava flow subsequently travelled {{convert|11|km|0}} north to the Nass River, where it filled the flat valley floor for an additional {{convert|10|km|0}}, making the entire lava flow {{convert|22.5|km}} long.<ref name="UY">{{cite web|title=Tseax Cone |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tsx_107 |access-date=January 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20060219232127/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tsx_107 |archive-date=February 19, 2006 }}</ref><ref name="AU"/> Native legends from Nisga'a people in the area tell of a prolonged period of disruption by the volcano, including the destruction of two Nisga'a villages known as Lax Ksiluux and Wii Lax K'abit.<ref name="AU"/><ref>{{cite web|publisher=Government of British Columbia|url=https://apps.gov.bc.ca/pub/bcgnws/names/40740.html |archive-url=https://web.archive.org/web/20070102034732/http://ilmbwww.gov.bc.ca/bcgn-bin/bcg10?name=40740 |url-status=live |archive-date=January 2, 2007 |title=BCGNIS Query Results|access-date=January 19, 2009}} </ref> Nisga'a people dug pits for shelter but at least 2,000 Nisga'a people were killed due to volcanic gases and poisonous smoke (most likely carbon dioxide).<ref name="UY"/><ref name="IK">{{cite web|last=Hickson |first=C.J. |author2=Ulmi, M. |title=Volcanoes of Canada |publisher=Natural Resources Canada |date=January 3, 2006 |url=http://www.bcminerals.ca/pdf/CanadianVolcanoes-CH2005.pdf |access-date=January 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20070810085815/http://www.bcminerals.ca/pdf/CanadianVolcanoes-CH2005.pdf |archive-date=August 10, 2007 }}</ref><ref name="AU"/> This is Canada's worst known geophysical disaster.<ref name="IK"/> It is the only eruption in Canada for which legends of First Nations people have been proven true.<ref name="UY"/> As of 1993, the Tseax Cone quietly rests in Nisga'a Memorial Lava Bed Provincial Park.<ref name="UY"/>
thumb|right|The eruption report in the Atlin area of northwestern British Columbia, Canada (formerly in Alaska, United States) by The New York Times on December 1, 1898 An eruption was reported by placer miners on November 8, 1898 in the Atlin Volcanic Field of the Northern Cordilleran Volcanic Province adjacent to Ruby Mountain volcano {{convert|80|km}} south of Gladys Lake when volcanic ash was said to be falling for many days.<ref name="ANC">{{cite gvp|vn=320030|title=Atlin Volcanic Field|access-date=March 1, 2009}}</ref><ref>{{cite gvp|vn=320030|vtab=Eruptions|title=Atlin Volcanic Field: Eruptive History|access-date=March 1, 2009}}</ref> During the eruption the adjacent placer miners were able to work at nights due to incandescent glow from the eruption.<ref name="ANC"/> A news report published on December 1, 1898 by the American newspaper publisher The New York Times stated: ''Kinslee and T. P. James, Denver mining men who with Col. Hughes of Rossland have just returned from Alaska, report that a volcano is in active eruption about fifty miles from Atlin City. No name has yet been given to the volcano, but the officials of Atlin are preparing for a trip of inspection and will christen it. It is said to be the second in a string of four mountains lying fifty miles due south of Lake Gladys, all of which are more than 1,400 feet high.''<ref>{{cite news |title=Active Volcano Near Atlin, Alaska. (Published 1898) |url=https://www.nytimes.com/1898/12/01/archives/active-volcano-near-atlin-alaska.html |work=The New York Times |date=1 December 1898 }}</ref> In 1898 the Atlin area was in dispute with the Alaska-British Columbia boundary, leading American news broadcasters stating the Atlin area was in Alaska rather than in northwestern British Columbia. This Alaska-British Columbia boundary dispute was eventually resolved by arbitration in 1903 and no evidence for the 1898 eruption has been found, leading researchers to speculate about the eruption and report it as uncertain.<ref name="ANC"/>
thumb|left|Recently erupted pahoehoe lava flow at the Blue River The Volcano at the southern end of the Northern Cordilleran Volcanic Province just north of the Alaska-British Columbia boundary is probably the youngest in Canada.<ref name="PP">{{cite web|last=Edwards |first=Ben |title=Lava Fork, NW British Columbia/SE Alaska |work=VolcanoWorld |date=November 2000 |url=http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/canada/Final-LF.html |access-date=January 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20100731225812/http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/canada/Final-LF.html |archive-date=July 31, 2010 }}</ref> It is a poorly built cinder cone made of loose volcanic ash, lapilli-sized tephra and volcanic bombs.<ref name="PP"/><ref name="AW">{{cite web|title=Lava Fork |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=August 19, 2005 |url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_garibaldi_e.php |access-date=January 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20060219225103/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_garibaldi_e.php |archive-date=February 19, 2006 }}</ref> Lying above a remote mountain ridge in the Boundary Ranges of the Coast Mountains, it is responsible for lava flow eruptions in 1904 and older that traveled south {{convert|5|km|0}} through river valleys where they crossed the border into the U.S. state of Alaska and dammed the Blue River, a short tributary of the Unuk River.<ref name="PP"/> In doing so it formed several small lakes.<ref name="PP"/> This eruption had a massive effect on fish, plant and animal inhabitants of the valley, but there is no record of its impact on people, most likely because people were not in the remote area.<ref name="HEPO"/> The entire length of the lava flows are at least {{convert|22|km}} and still contain the original lava features from when they were erupted, including pressure ridges and lava channels.<ref name="PP"/><ref name="AW"/> However, sections of the lava flows have collapsed into underlying lava tubes to form cavities.<ref name="AW"/> Tephra and scoria from The Volcano covers adjacent mountain ridges and even through it is very young, it has been reduced by erosion from alpine glacial ice found in the heavily glaciated Coast Mountains.<ref name="AW"/> The estimated volume of lava and ash from The Volcano is {{convert|2.2|km3|cumi|0|abbr=on}}.<ref name="AW"/>
thumb|right|Map of the Nazko earthquake swarm in 2007 A series of earthquakes of less than magnitude 3.0 were recorded by seismographs in the Baezaeko River region {{convert|20|km}} west of Nazko Cone in the Anahim Volcanic Belt on October 9, 2007.<ref name="AILO">{{cite web|publisher=Natural Resources Canada |url=http://earthquakescanada.nrcan.gc.ca/nazko/nazko_summary_e.php |title=Nazko Cone |date=July 9, 2008 |access-date=January 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20080604034042/http://earthquakescanada.nrcan.gc.ca/nazko/nazko_summary_e.php |archive-date=June 4, 2008 }}</ref> The cause of these earthquakes was magma intruding into rock {{convert|25|km}} below the surface.<ref name="AILO"/> Since then more than 1,000 small earthquakes have been recorded.<ref>{{cite web|publisher=Natural Resources Canada |url=http://earthquakescanada.nrcan.gc.ca/nazko/nazko_chronology_e.php |title=Chronology of Events in 2007 at Nazko Cone |date=July 9, 2008 |access-date=January 21, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20071205104714/http://earthquakescanada.nrcan.gc.ca/nazko/nazko_chronology_e.php |archive-date=December 5, 2007 }}</ref> Because of the small size of the earthquake swarms, Natural Resources Canada has added more seismographs in the region for better location and depth accuracy.<ref name="AILO"/> However, the size and number of the 2007 earthquake swarms indicate there is currently no threat of an eruption.<ref name="AILO"/> Before magma could erupt in the area adjacent to Nazko Cone, it is expected the size and number of the earthquakes would rise considerably, presaging an eruption.<ref name="AILO"/>
== Mitigation and vulnerability == {{See also|Public Safety Canada}} thumb|right|Map of young volcanoes in Northern and Western Canada and adjacent regions In Canada, even though volcanoes pose significant threats to local communities and any sizable eruption would affect Canada's economy, the work of understanding the frequency and eruption characteristics at volcanoes in Canada is a slow process.<ref name="HEPO">{{cite web|title=Volcanoes |publisher=Natural Resources Canada |date=September 5, 2007 |url=http://atlas.nrcan.gc.ca/site/english/maps/environment/naturalhazards/volcanoes/1 |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090217001048/http://atlas.nrcan.gc.ca/site/english/maps/environment/naturalhazards/volcanoes/1 |archive-date=February 17, 2009 }}</ref> This is because most of Canada's dormant and potentially active volcanoes are located in isolated jagged regions, very few scientists study Canadian volcanoes and the provision of money in the Canadian government is limited.<ref name="HEPO"/> Because of these issues, scientists studying Canada's volcanoes have a basic understanding of Canada's volcanic heritage and how it might impact people in the future.<ref name="HEPO"/> Volcanologists are aware that certain areas in Canada have higher levels of volcanic activity than others and how eruptions in these areas might affect people and the environment they live in.<ref name="HEPO"/> When a volcano is showing evidence of volcanic activity, quick action will be required to better understand the process.<ref name="HEPO"/> The lowest possibility for an eruption in Canada per year is approximately 1/200; for a passive lava eruption the possibility is about 1/220, and for a major explosive eruption it is about 1/3333.<ref name="AKB"/> Even though volcanoes do not seem to be part of the everyday reality of Canadians, recurrent earthquakes and the formation of large mountain ranges in the Pacific Northwest indicate this part of Canada is still geologically active. The possibility of an eruption, even a large explosive one, cannot be ruled out. Quiet as they currently seem, volcanoes in Northern and Western Canada are part of the Pacific Ring of Fire.<ref name="HEPO"/> Along with volcanoes associated with recent earthquake activity, a scenario of an eruption at Mount Cayley in southwestern British Columbia illustrates how Western Canada is in danger to a volcanic eruption, which has not erupted for at least 310,000 years.<ref name="AKB"/><ref>{{cite web|publisher=Geological Survey of Canada |url=http://dsp-psd.communication.gc.ca/Collection/M44-2001-A11E.pdf |title=Preliminary petrography and chemistry of the Mount Cayley volcanic field, British Columbia |access-date=February 18, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20081219153514/http://dsp-psd.communication.gc.ca/Collection/M44-2001-A11E.pdf |archive-date=December 19, 2008 }}</ref> This impact is becoming even more likely as population in the Pacific Northwest increases and development spreads. The scenario is based on former eruptions in the north-south trending Garibaldi Volcanic Belt and includes both explosive and passive eruptions.<ref name="AKB"/> Its effect is mostly due to the attention of defenseless public services in canyons.<ref name="AKB"/> However, the threat from volcanoes outside of Canada seems much greater than the threat from volcanoes within Canada because of the lack of monitoring data at Canadian volcanoes and the age of most volcanoes in Canada is poorly known.<ref name="ZIV">{{cite web|title=Volcanic eruptions|work=Volcanoes of Canada|publisher=Geological Survey of Canada|date=February 18, 2009|url=http://gsc.nrcan.gc.ca/volcanoes/erupt_e.php|access-date=February 18, 2009|url-status=dead|archive-url=https://web.archive.org/web/20100220052524/http://gsc.nrcan.gc.ca/volcanoes/erupt_e.php|archive-date=February 20, 2010}}</ref> But for some, their minimal degree of erosion indicates they formed much less than 10,000 years ago, including the Milbanke Sound Group on Price Island, Dufferin Island, Swindle Island, Lake Island, and Lady Douglas Island in the Milbanke Sound area of coastal British Columbia.<ref name="ZIV"/> However, it is known volcanoes in the U.S. states of Alaska, Washington, Oregon and California have been more active in historic times than those within Canada.<ref name="ZPQ"/> Therefore, volcanoes in the United States are monitored with caution and attention by the United States Geological Survey.<ref name="ZPQ"/>
[[File:RockSlide 1200W.jpg|thumb|left|The Barrier in the Garibaldi Volcanic Belt poses a geohazard in southwestern British Columbia.]] Growing awareness of volcanism, especially the threat from volcanoes in the United States, has led to a number of changes in the way Canadians are dealing with volcanic hazards. For example, The Barrier, an unstable lava dam retaining the Garibaldi Lake system of southwestern British Columbia, has in the past unleashed several debris flows, most recently in 1855–1856.<ref name="AZO">{{cite web|title=Garibaldi volcanic belt: Garibaldi Lake volcanic field |work=Catalogue of Canadian volcanoes |publisher=Geological Survey of Canada |date=February 13, 2008 |url=http://cgc.rncan.gc.ca/volcanoes/cat/feature_garibaldi_e.php |access-date=February 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20070311031101/http://cgc.rncan.gc.ca/volcanoes/cat/feature_garibaldi_e.php |archive-date=March 11, 2007 }}</ref> This led to the evacuation of the small resort village of Garibaldi nearby and the relocation of residents to new recreational subdivisions away from the hazard zone.<ref name="AZO"/> Should The Barrier completely collapse, Garibaldi Lake would be entirely released and downstream damage in the Cheakamus and Squamish rivers would be considerable, including major damage to the town of Squamish and possibly an impact-wave on the waters of Howe Sound that would reach Vancouver Island. The Interagency Volcanic Event Notification Plan, Canada's volcanic emergency notification program, was established to outline the notification procedure of some of the main agencies that would be involved in response to a volcanic eruption in Canada, an eruption close to Canada's borders, or an eruption significant enough to have an effect on Canada and its people.<ref>{{cite web|title=Interagency Volcanic Event Notification Plan: Western Canada |publisher=Natural Resources Canada |date=May 1, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/pdf/ivenp_e.pdf |access-date=February 19, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110604174944/http://gsc.nrcan.gc.ca/volcanoes/pdf/ivenp_e.pdf |archive-date=June 4, 2011 }}</ref> It focuses primarily on aviation safety because jet aircraft can quickly enter areas of volcanic ash.<ref name="HEPO"/> The program notifies all impacted agencies that have to deal with volcanic events.<ref name="HEPO"/> Aircraft are rerouted away from hazardous ash and people on the ground are notified of potential ash fall.<ref name="HEPO"/>
=== Monitoring === Currently no volcanoes in Canada are monitored closely enough by the Geological Survey of Canada to ascertain how active their magma chambers are.<ref name="ZPQ">{{cite web|title=Monitoring volcanoes |work=Volcanoes of Canada |publisher=Geological Survey of Canada |date=February 12, 2008 |url=http://gsc.nrcan.gc.ca/volcanoes/mon_e.php |access-date=January 22, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20080507152523/http://gsc.nrcan.gc.ca/volcanoes/mon_e.php |archive-date=May 7, 2008 }}</ref> An existing network of seismographs has been established to monitor tectonic earthquakes and is too far away to provide a good indication of what is happening beneath them.<ref name="ZPQ"/> It may sense an increase in activity if a volcano becomes very restless, but this may only provide a warning for a large eruption.<ref name="ZPQ"/> It might detect activity only once a volcano has started erupting.<ref name="ZPQ"/>
== See also == {{Portal|Geography|Canada}} * List of volcanoes in Canada * Geography of Canada
== References == {{Reflist|2}}
== External links == {{Commons category|Volcanoes of Canada}} * [https://web.archive.org/web/20070223170422/http://cgc.rncan.gc.ca/volcanoes/cat/index_e.php Catalogue of Canadian volcanoes] * [https://vulcan.wr.usgs.gov/Volcanoes/Canada/framework.html CVO Menu - Canada Volcanoes and Volcanics] * [https://web.archive.org/web/20090204102548/http://volcano.oregonstate.edu/vwdocs/volc_images/north_america/canada/Canada.html Overview of Canadian volcanoes/Canada volcanoes] * [http://www.volcano.si.edu/world/region.cfm?rnum=1200 Global Volcanism Program: Volcanoes of Canada and the western USA] * [https://volcano.si.edu/database/search_volcano_results.cfm GVP: Volcanoes of Canada] * [https://open.library.ubc.ca/cIRcle/collections/ubctheses/24/items/1.0347288 Erica A. Massey: A Comparative Study of Glaciovolcanic Palagonitization of Tholeitic and Alkaline Sideromelane in Helgafell, Icland, and Wells Gray-Clearwater Volcanic Filed, BC, Canada. B.Sc., The University of British Columbia, 2014]
{{Canadian volcanism}} {{Canada topics}}
{{DEFAULTSORT:Volcanism Of Canada}} Category:Volcanism of Canada Category:Geographic areas of seismological interest Category:Natural hazards in Canada