{{Short description|Cinder cone in British Columbia, Canada}} {{Redirect|Tseax|the river|Ksi Sii Aks}} {{Featured article}} {{Use Canadian English|date=January 2025}} {{Use mdy dates|date=January 2025}} {{Infobox mountain | name = Tseax Cone | etymology = [[Ksi Sii Aks|Tseax River]] (Ksi Sii Aks){{sfn|BC Geographical Names: Ksi Sii Aks}} | native_name = {{native name|ncg|Wil Ksi Bax̱hl Mihl}}{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=363}} | translation = Where the Fire Ran Out{{sfn|Postmedia Network|2019}} | image = File:Tseax Cone.jpg | image_alt = Aerial view of a sparsely tree-covered, cone-shaped volcano with a crater on its summit surrounded by forest and a lake in the background. | image_caption = Tseax Cone with [[Melita Lake]] in the background | mapframe = yes | mapframe-caption = Location in [[Nisga'a Memorial Lava Bed Provincial Park|Nisga'a Memorial Lava Bed Park]] | mapframe-zoom = 9 | mapframe-wikidata = yes | elevation_m = 609 | elevation_ref = {{sfn|Global Volcanism Program: Tseax River Cone|loc=General Information}} | coordinates = {{coord|55|06|38|N|128|53|56|W|type:mountain_region:CA-BC|format=dms|display=inline,title}} | coordinates_ref = {{sfn|BC Geographical Names: Tseax Cone}} | map = Canada British Columbia | map_alt = Relief map of British Columbia pinpointing the location of Tseax Cone | map_caption = Location in British Columbia | label_position = bottom | country = [[Canada]]{{sfn|Williams-Jones et al.|2020|p=1238}} | region_type = [[Provinces and territories of Canada|Province]] | region = [[British Columbia]]{{sfn|Williams-Jones et al.|2020|p=1238}} | district = [[Cassiar Land District]]{{sfn|BC Geographical Names: Tseax Cone}} | part_type = [[Protected area]] | part = [[Nisga'a Memorial Lava Bed Provincial Park]]{{sfn|Natural Resources Canada: Tseax Cone}} | range = [[Nass Ranges]]{{sfn|Geographical Names Data Base: Tseax Cone}} | topo_maker = [[National Topographic System|NTS]] | topo_map = {{Canada NTS Map Sheet|103|P|2}}{{sfn|BC Geographical Names: Tseax Cone}} | age = Less than 800 years old{{sfn|Williams-Jones et al.|2020|p=1242}} | type = [[Cinder cone]]{{sfn|Natural Resources Canada: Tseax Cone}} | geology = [[Basanite]] and [[trachybasalt]]{{sfn|Williams-Jones et al.|2020|p=1238}} | volcanic_zone = [[Northern Cordilleran Volcanic Province|Northern Cordilleran Province]]{{sfn|Slaymaker|2017|p=52}} | last_eruption = 1690 ± 150 years{{sfn|Global Volcanism Program: Tseax River Cone|loc=Eruptive History}} }}
'''Tseax Cone''' ({{IPAc-en|ˈ|s|iː|æ|k|s}} {{respell|SEE|aks}}) is a small [[volcano]] in the [[Nass Ranges]] of the [[Hazelton Mountains]] in northwestern [[British Columbia]], Canada. It has an [[elevation]] of {{convert|609|m|ft|abbr=off}} and lies within an east–west valley through which a [[tributary]] of the [[Tseax River]] flows. The volcano consists of two nested structures and was the source of four [[lava]] flows that descended into neighbouring valleys. A [[parasitic cone|secondary eruptive centre]] lies just north of Tseax Cone on the opposite side of [[Melita Lake]]. It probably formed simultaneously with Tseax Cone, but the timing of [[volcanism]] at the two eruptive centres is not precisely known; both were formed by volcanic activity sometime in the last 800 years.
The exact timing of volcanism at Tseax Cone has been a subject of controversy because there are no direct written accounts; [[radiocarbon dating]] of plants killed by lava or [[ejecta]] from the volcano has yielded ages as old as 625 ± 70 years to as young as 190 ± 15 years. There is also controversy over whether the volcano was formed during one or more distinct episodes of eruptive activity. The single eruptive episode hypothesis has been proposed by researchers as early as 1923 whereas a multi-eruption hypothesis was proposed in 1978. Most research suggests that Tseax Cone was formed during one episode of eruptive activity; new data supporting this hypothesis was reported in 2020.
Tseax Cone is the subject of legends told by the local [[Indigenous peoples in Canada|indigenous people]]. They describe the destruction of villages along the [[Nass River]] by the volcano and the death of several people from inhaling [[volcanic gas|volcanic fumes]], although other causes of death may have been involved. As many as 2,000 people are claimed to have been killed by an eruption from Tseax Cone; this would make it the deadliest geological disaster in Canada and the second-worst [[natural disaster]] in Canadian history by death toll. Tseax Cone has therefore been described as the deadliest volcano in Canada. Renewed eruptions from the volcano could start [[wildfire]]s and block local streams with lava flows.
Tseax Cone lies within an [[ecoregion]] characterized by mountainous [[terrain]] and several streams. [[Rainforest]]s occur at the volcano, as well as numerous species of mammals. [[Lichen]]s and [[moss]]es cover most of the lava flows that have issued from Tseax Cone, although rainforests and waterbodies also obscure them. After at least 20 years of pleas for [[environmental protection|protection]], the volcano and lava flows were established as [[Nisga'a Memorial Lava Bed Provincial Park]] in 1992. Tseax Cone and its lava flows can be accessed via [[provincial highway]]s and backcountry roads.
==Names and etymology== Tseax Cone has been variously called ''Aiyansh Volcano'', ''Aiyansh River Volcano'', ''Tseax River Cone'' and ''Tseax Volcano''.{{sfn|Williams-Jones et al.|2020|p=1239}} ''Aiyansh'' comes from a [[Nisga'a language|Nisga'a word]] meaning {{gloss|leafing early}} or {{gloss|early leaves}}, whereas ''Tseax'' comes from a Nisga'a word meaning {{gloss|new water}}.{{sfn|Akrigg|Akrigg|1997|pp=3, 273}} ''Tseax'' is possibly a reference to the disturbed drainage patterns of the [[Tseax River]] caused by a volcanic eruption from the cone.{{sfn|Akrigg|Akrigg|1997|p=273}} The well-established [[local name]] for the volcano, ''Tseax Cone'', became official on December 13, 1991, and was adopted on the [[National Topographic System]] map 103P/2.{{sfn|BC Geographical Names: Tseax Cone}}{{sfn|Geographical Names Data Base: Tseax Cone}} To the local [[Nisga'a people]], Tseax Cone is known as {{lang|ncg|Wil Ksi Bax̱hl Mihl}}; in their language, it means {{gloss|Where the Fire Ran Out}}, which is a reference to the volcanic eruption that sent lava spewing out of the volcano.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=363}}{{sfn|Postmedia Network|2019}}
==Geography== ===Location and climate=== Tseax Cone is about {{Convert|60|km|mi|abbr=off}} north of [[Terrace, British Columbia|Terrace]] near the Nisga'a villages of [[Gitwinksihlkw]] and [[Gitlaxt'aamiks]] in [[Cassiar Land District]] of northwestern [[British Columbia]], Canada.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=363}}{{sfn|BC Geographical Names: Gitwinksihlkw}}{{sfn|BC Geographical Names: Cassiar Land District}}{{sfn|BC Geographical Names: New Aiyansh}} It lies within a steep-sided, {{Convert|5|km|mi|abbr=on}} long, east–west valley penetrating the [[Nass Ranges]] of the [[Hazelton Mountains]].{{sfn|Geographical Names Data Base: Tseax Cone}}{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=364}}{{sfn|Denton|1975|p=662}} Tseax Cone is situated at the outlet of [[Melita Lake]], an expansion of [[Crater Creek]] which flows west into the Tseax River.{{sfn|BC Geographical Names: Tseax Cone}}{{sfn|BC Geographical Names: Melita Lake}}{{sfn|BC Geographical Names: Crater Creek}} Crater Creek gets its name from being in association with Tseax Cone which is located on the eastern side of the creek.{{sfn|BC Geographical Names: Tseax Cone}}{{sfn|BC Geographical Names: Crater Creek}} The Nass Mountains Ecosection is the main [[ecosection]] at the cone.{{sfn|Demarchi|2011|p=36}}
The area has a [[Geography of British Columbia#Climate|climate]] that is somewhat transitional between those of coastal and [[continental climate|continental]] regimes. It is wetter than other areas in the Nass Ranges Ecoregion due to air entering from the [[British Columbia Coast|Pacific Coast]]. Much of this Pacific air enters via the [[Skeena River]] valley or flows over the [[Kitimat Ranges]], resulting in cloud cover and heavy rain.{{sfn|Demarchi|2011|p=36}} Short periods of extreme cold temperatures and deep snow occasionally occur as a result of cold [[Arctic]] air invading from the north.{{sfn|Demarchi|2011|pp=36, 37}}
===Plants and animals=== [[File:Lava Beds of Nass Valley, British Columbia.jpg|thumb|right|alt=Jagged, moss-covered rocks in a valley bounded by lightly snow-covered mountains|Moss-covered lava in [[Nass Valley]]]] [[Lichen]]s and [[moss]]es cover large portions of lava flows originating from Tseax Cone.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|pp=365, 367}} They range in colour from green to yellow, reach thicknesses of a few centimetres and give the illusion that the lava flows are covered in fur.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|pp=365, 367}}{{sfn|Gentles|1972|p=252}} Also present on the lava flows in very small quantities are grasses and smaller shrubs.{{sfn|Gentles|1972|p=252}} In the Tseax River valley, the lava flows have been almost completely covered by dense rainforest; [[Biogeoclimatic zones of British Columbia#Coastal Western Hemlock (CWH)|coastal western hemlock]] and [[Biogeoclimatic zones of British Columbia#Mountain Hemlock (MH)|subalpine mountain hemlock]] form rainforests in the area.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|pp=364, 367}}{{sfn|Demarchi|2011|p=37}} [[Fauna of Canada|Wildlife]] in the area includes [[marmot]]s, [[Capra (genus)|goats]], [[bear]]s and [[moose]].{{sfn|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}}
Despite being covered by lichens, mosses and rainforests, the lava flows are easily recognizable from aerial and satellite imagery, as well as [[field observations]].{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|pp=365, 367}} However, this may change by the end of the 21st century as [[lodgepole pine]] and [[Populus|cottonwood]] forests continue to develop on the lava flows in an increasingly wetter and milder climate. The growth of these forests is bolstered by the deposition of [[silt]] on the lava flows by local streams, providing soil for vegetation.{{sfn|Government of British Columbia}}
==Geology and geomorphology== ===Background=== Tseax Cone is one of the southernmost volcanoes in the [[Northern Cordilleran Volcanic Province]].{{sfn|Slaymaker|2017|p=52}} This is a broad area of [[shield volcano]]es, [[lava dome]]s, [[cinder cone]]s and [[stratovolcano]]es extending from northwestern British Columbia northwards through [[Yukon]] into easternmost [[Alaska]].{{sfn|Edwards|Russell|2000|pp=1280, 1281, 1283, 1284}} The dominant rocks comprising these volcanoes are [[alkali basalt]]s and [[hawaiite]]s, but [[nephelinite]], [[basanite]] and [[peralkaline]]{{efn|''Peralkaline rocks'' are magmatic rocks that have a higher ratio of sodium and potassium to aluminum.{{sfn|McGraw Hill|2003|p=253}}}} [[phonolite]], [[trachyte]] and [[comendite]] are locally abundant. These rocks were deposited by volcanic eruptions from 20 million years ago to as recently as a few hundred years ago. Volcanism in the Northern Cordilleran Volcanic Province is thought to be due to [[rift]]ing of the [[North American Cordillera]], driven by changes in relative [[plate tectonics|plate motion]] between the [[North American Plate|North American]] and [[Pacific Plate|Pacific]] plates.{{sfn|Edwards|Russell|2000|p=1280}}
===Petrology=== [[File:Tseax vent 2013.jpeg|thumb|right|alt=A sparsely tree-covered volcanic cone with a bowl-shaped crater on the top|Tseax Cone from the southeast]] Tseax Cone and its eruptive products are basanitic, [[trachybasaltic]] or [[alkali]] basaltic in composition.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=365}}{{sfn|Roberts|McCuaig|2001|p=319}} They are rich in iron-titanium [[Redox|oxides]] and were produced by a low degree of [[partial melting]] {{convert|55–62|km|mi|abbr=on}} below the surface in the upper [[Earth's crust|crust]].{{sfn|Le Moigne|2020|pp=81, 82}} [[Olivine]], [[plagioclase]] and the iron-titanium oxides are in the form of [[phenocryst]]s{{efn|''Phenocrysts'' are large, conspicuous crystals in magmatic rocks with [[porphyritic]] texture.{{sfn|McGraw Hill|2003|p=257}}}} whereas [[clinopyroxene]] occurs as a [[matrix (geology)|matrix]] mineral.{{sfn|Le Moigne|Vigouroux|Russell|Williams-Jones|2022|pp=7, 8}} The lack of clinopyroxene phenocrysts in Tseax Cone lavas is a phenomenon commonly observed in other [[mafic]]{{efn|''Mafic'' pertains to magmatic rocks that are relatively rich in [[iron]] and [[magnesium]], relative to [[silicium]].{{sfn|Pinti|2011|p=938}}}} lavas throughout the Northern Cordilleran Volcanic Province.{{sfn|Le Moigne|Vigouroux|Russell|Williams-Jones|2022|p=17}} Tseax Cone and its eruptive products rest [[unconformity|unconformably]] on [[sedimentary rock]]s of the Bowser Lake Group, a [[group (stratigraphy)|geological group]] of [[Jurassic]] and [[Cretaceous]] age consisting of grey [[sandstone]]s and dark grey and black [[conglomerate (geology)|conglomerates]], [[siltstone]]s and [[mudstone]]s.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=364}}
Lava and [[tephra]] from Tseax Cone cover about {{convert|36|km2|mi2|abbr=on}} and have a total volume of around {{convert|0.5|km3|mi3|abbr=on}}; the volume of this volcanic material is similar to that produced during [[Mauna Loa]]'s [[1984 eruption of Mauna Loa|1984 eruption]] and [[Kīlauea]]'s [[2018 lower Puna eruption|fissure 8 eruption in 2018]].{{sfn|Le Moigne|2020|p=85}}{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=368}} The Tseax Cone lavas are thought to have been emplaced at high speed during a short period of time, which may have been partially due to eruption rate and [[topography]]. Their liquidus viscosities are comparable to [[basalt]]s of [[Mount Etna]] and the [[Hawaiian Islands]], as well as the [[foidite]] lavas of [[Mount Nyiragongo]] and the [[tephrite]] lavas of [[Nyamuragira]].{{sfn|Le Moigne|Vigouroux|Russell|Williams-Jones|2022|p=15}} It is possible that the lava erupted from Tseax Cone rose along the same [[fault (geology)|faults]] as those at the [[Lakelse Hot Springs]] south of Terrace, which are the hottest [[geothermal spring]]s in Canada.{{sfn|Turner et al.|2007|pp=9–11}}
===Structure=== Tseax Cone has an [[elevation]] of {{convert|609|m|ft|abbr=on}} and consists of two nested structures: a smaller inner cone and a larger external [[spatter rampart]].{{sfn|Global Volcanism Program: Tseax River Cone|loc=General Information}}{{sfn|Le Moigne et al.|2022|p=7}} The younger inner cone is {{convert|65|–|75|m|ft|abbr=on}} high and {{convert|290|m|ft|abbr=on}} in diameter, consisting mainly of black [[ejecta]] such as [[scoria]], ballistics and [[lapilli]].{{sfn|Natural Resources Canada: Tseax Cone}}{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=365}}{{sfn|Le Moigne et al.|2022|p=7}} It contains an approximately {{Convert|33|m|ft|adj=mid|abbr=on}} deep [[volcanic crater]] with a diameter of {{convert|80|m|ft|abbr=on}}.{{sfn|Le Moigne et al.|2022|p=7}} The older external spatter rampart, which has also been described as a cone, is about {{convert|15|–|25|m|ft|abbr=on}} high and {{convert|460|m|ft|abbr=on}} in diameter.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=365}}{{sfn|Le Moigne et al.|2022|p=7}} It consists of spatter and scoria that ranges in colour from reddish to brownish and black to grey.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=365}} Each structure was formed by a different [[types of volcanic eruptions|style of volcanic activity]]; the spatter rampart was created by [[Hawaiian eruption|Hawaiian]]-style [[lava fountain]]ing whereas the inner cone was created by low-intensity [[Strombolian eruption|Strombolian]] explosions.{{sfn|Le Moigne|2020|p=85}} The entire structure of Tseax Cone has been variously described as a cinder cone, a [[pyroclastic cone]] or a [[tephra cone]].{{sfn|Global Volcanism Program: Tseax River Cone|loc=General Information}}{{sfn|Williams-Jones et al.|2020|p=1238}}{{sfn|Natural Resources Canada: Tseax Cone}}
About {{Convert|470|m|ft|abbr=on}} north of Tseax Cone and {{Convert|150|–|200|m|ft|abbr=on}} north of Melita Lake is a much smaller, unnamed asymmetrical [[satellite cone]]. It is about {{Convert|20|m|ft|abbr=on}} high, {{convert|50|–|55|m|ft|abbr=on}} in diameter and heavily oxidized, containing a {{Convert|4|m|ft|abbr=on}} deep and {{Convert|7|m|ft|abbr=on}} in diameter summit crater. Extending southwest of the satellite cone is an eruptive [[fissure vent|fissure]] consisting of three or four tephra mounds.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=365}}{{sfn|Williams-Jones et al.|2020|p=1241}} These mounds are a few metres high and are completely covered by black tephra. Red oxidized tephra beneath the black tephra was deposited by lava fountaining at the larger satellite cone.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=365}}
===Air-fall tephra layer=== The inner cone was the source of an elongated tephra layer that extends {{convert|2.5|km|mi|abbr=on}} to the northeast, suggesting a southwesterly wind at the time of eruption.{{sfn|Le Moigne et al.|2022|p=7}} It contains millimetre-sized sandstones and siltstones derived from the underlying Bowser Lake Group, as well as fine-grained [[metamorphic rock|metamorphic]] and [[plutonic rock|plutonic]] rocks; these [[clast]]s make up about 0.5% of the total volume of the tephra layer.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=364}}{{sfn|Le Moigne et al.|2022|p=7}} The tephra layer has an estimated volume of {{convert|2.5000000|–|3.4000000|m3|ft3|abbr=on}}, suggesting that it was deposited by a [[Volcanic Explosivity Index|VEI]]-2 eruption. The volume of this tephra deposit is the first to be calculated for a mafic eruption in Canada.{{sfn|Osman et al.|2026|p=1}}
===Lava flows=== Tseax Cone was the source of four distinct lava flows, all of which were probably erupted over a timespan of weeks to a few months.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=363}}{{sfn|Le Moigne et al.|2022|p=1}} The first flow is the longest and most voluminous, accounting for about 84% of the total volume of lava erupted from Tseax Cone.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}} It travelled {{Convert|31.6|km|mi|abbr=on}} through Crater Creek and Tseax River valleys to the [[Nass River]] where it forms a {{Convert|3|km|mi|abbr=on}} wide and {{Convert|12|km|mi|abbr=on}} long [[lava plain]] with an elevation of about {{convert|50|m|ft|abbr=on}}.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}}{{sfn|Symons|1975|p=2622}} This lava flow was most likely voluminous enough to block the Nass River for a short period of time.{{sfn|Natural Resources Canada: Tseax Cone}} The second flow, representing about 13% of the total volume of lava, travelled {{Convert|21.6|km|mi|abbr=on}} through Crater Creek valley to near the mouth of the Tseax River valley.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}} Both of these lava flows are in the form of [[pāhoehoe]]{{efn|''Pāhoehoe'' is basaltic lava with a smooth, glassy, undulating and porous surface.{{sfn|McGraw Hill|2003|p=238}}}} and are poor in phenocrysts, having issued from the spatter rampart.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}}{{sfn|Le Moigne|2020|p=88}} They are among the longest lava flows in the [[Canadian Cordillera]]; lava flows more than {{convert|10|km|mi|abbr=on}} long in this [[cordillera]] are usually basaltic in composition.{{sfn|Stasiuk|Hickson|Mulder|2003|p=563}} The third flow accounts for less than 2% of the total volume of lava erupted from Tseax Cone, having travelled {{Convert|7.2|km|mi|abbr=on}} through Crater Creek valley to near Ross Lake in the Tseax River valley. The fourth flow is the shortest and least voluminous of the four lava flows; it represents about 1% of the total lava volume and travelled Crater Creek for {{Convert|5.3|km|mi|abbr=on}}.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}} These latter two lava flows are in the form of [[ʻaʻā]]{{efn|''ʻAʻā'' is lava with a rough rubbly surface composed of broken blocks called clinkers.{{sfn|United States Geological Survey|2018}}}} and are rich in phenocrysts, having issued from the inner cone.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}}{{sfn|Le Moigne|2020|p=88}}
[[File:Nisga'a Memorial Lava Beds Provincial Park tree mould.jpg|thumb|left|alt=A circular hole in volcanic rock formed by a burned out tree trunk|A horizontal [[lava tree mold]]]] All four lava flows contain intact and collapsed [[lava tube]]s, as well as [[lava tree mold]]s.{{sfn|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}}{{sfn|Williams-Jones et al.|2020|p=1241}} At least four lava tubes are situated adjacent to and extend under Tseax Cone. They lie at an elevation of {{convert|590|m|ft|abbr=on}} and were the subject of a [[glaciological]] study in 1975. At the time of study, two of the four lava tubes were found to be ice-free most of the year. One of these tubes contained a small [[braided stream]] whereas the other tube was dry and did not contain any stream sediments. The lack of stream sediments in the latter lava tube indicated that it remained dry and did not contain permanent ice deposits.{{sfn|Marshall|1975|p=399}} Floors of ice were blocking the other two slightly higher tubes. As much as {{convert|20|cm|in|abbr=off}} of water was covering the ice in summer, indicating that unlike the other two lava tubes, they did not have exit points for water runoff at their lowermost levels. There was no evidence that the ice was [[dissipating]] as in many other [[ice cave]]s despite an approximate mean annual temperature of {{convert|5|C|F|abbr=off}}. The [[petrographic]] characteristics of the ice deposits were found to be similar to those in alpine caves such as [[Eisriesenwelt Cave]] in [[Austria]] and [[Coulthard Cave]] in the [[Canadian Rockies]].{{sfn|Marshall|1975|p=400}}
The eruption of the Tseax Cone lava flows had a radical impact on the landscape due to their sudden inundation of the Tseax River valley and the Nass River [[floodplain]].{{sfn|Roberts|McCuaig|2001|pp=320, 323}} Their disruption of the existing [[drainage system (geomorphology)|drainage system]] resulted in the formation of new [[channel (geography)|channel]]s and [[geomorphic]] features such as [[lava dam|lava-dammed]] lakes, [[alluvial fan]] blockages and an inversion of [[topographic relief]].{{sfn|Roberts|McCuaig|2001|pp=320–323}} The Tseax River was forced to abandon its alluvial channel in favour of [[bedrock]] channels along the lava flows, although in some places one or more channels flow on the lava.{{sfn|Roberts|McCuaig|2001|pp=322, 323}} [[Vetter Creek]], a tributary of the Nass River, flows along the western side of the lava and then disappears under the lava-covered Nass River floodplain through a series of [[sinkhole]]s.{{sfn|Roberts|McCuaig|2001|p=323}}{{sfn|BC Geographical Names: Vetter Creek}} The lower portions of several alluvial fans are buried under the lava flows, including the Vetter fan which is among the largest.{{sfn|Roberts|McCuaig|2001|p=321}} Damming of Crater Creek and the Tseax River has resulted in Melita Lake and [[Lava Lake (British Columbia)|Lava Lake]] ponding behind the lava flows, although Lava Lake had already existed before the lava was erupted; it merely increased in depth.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}} Ross Lake overlies lava flows in the Tseax River valley north of Lava Lake.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=367}}{{sfn|BC Geographical Names: Ross Lake}}
===Age controversy=== The exact timing of [[volcanism]] at Tseax Cone has been a subject of controversy because there are no direct written accounts.{{sfn|Williams-Jones et al.|2020|pp=1241, 1250}} Reports of the rich [[oral history]] of the local Nisga'a people by [[missionaries]] as early as the 1910s suggest that Tseax Cone was erupting around 1770.{{sfn|Williams-Jones et al.|2020|pp=1238, 1241}} However, the credibility of these reports has been disputed due to possible poor translation from Nisga'a to English. G. Hanson wrote in a 1923 Canada [[Minister of Mines (Canada)|Department of Mines]] report that 170-year-old trees were found growing on lava from Tseax Cone; this would indicate an eruption prior to 1753. In 1935, [[Marius Barbeau]] concluded in the ''[[Canadian Geographical Journal]]'' that the latest eruption at Tseax Cone occurred in the late 18th century.{{sfn|Williams-Jones et al.|2020|p=1241}} In 1977, G. P. V. Akrigg and H. B. Akrigg speculated in ''British Columbia Chronicle, 1847–1871: Gold & Colonists'' that the Tseax Cone eruption was witnessed by naval officer [[Juan Francisco de la Bodega y Quadra]] on August 24, 1775. However, this is extremely unlikely because Bodega y Quadra's [[schooner]], the ''Sonora'', was anchored more than {{convert|280|km|mi|abbr=on}} west of Tseax Cone across mountainous terrain.{{sfn|Williams-Jones et al.|2020|p=1250}} Michael D. Higgins proposed in a 2008 ''[[Journal of Volcanology and Geothermal Research]]'' article that the [[1700 Cascadia earthquake]] may have caused the latest Tseax Cone eruption by destabilizing a subterranean [[magmatic]] system.{{sfn|Higgins|2009|p=149}}
[[File:Nass Valley Lava Beds.jpg|thumb|left|alt=A field of moss-covered rocks with a couple trees in the foreground and snow-covered mountains in the background.|Tseax Cone lava flow in Nass Valley]] [[Radiocarbon dating]] of trees killed by lava from Tseax Cone has also given inconclusive results. A lava-encased cottonwood near the Nass River was reported by Sutherland Brown in 1969 and [[Jack Souther]] in 1970 to have yielded a radiocarbon date of 220 ± 130 years. However, Lowdon ''et al.'' stated in a 1971 [[Radiocarbon (journal)|Radiocarbon]] article that this date was uncorrected and should in fact be 250 ± 130 years.{{sfn|Williams-Jones et al.|2020|p=1241}} In 2001, M. C. Roberts and S. McCuaig reported in ''[[The Canadian Geographer]]'' that a wood fragment of a lava-encased tree yielded a radiocarbon date of 220 ± 130 years; they gave a corrected date of 230 ± 50 years.{{sfn|Williams-Jones et al.|2020|pp=1241, 1242}} These two radiocarbon dates were recalibrated by Michael D. Higgins in 2008 using [[calibration]] software and reinterpreted the age of the Tseax Cone eruption at between 1668 and 1714.{{sfn|Williams-Jones et al.|2020|p=1242}}{{sfn|Higgins|2009|pp=150, 151}} Charred wood beneath tephra about {{Convert|890|m|ft|abbr=on}} northwest of Tseax Cone was reported by Williams-Jones ''et al.'' in 2020 to have yielded radiocarbon dates of 190 ± 15 years and 390 ± 15 years.{{sfn|Williams-Jones et al.|2020|pp=1239, 1242}} These dates suggest that Tseax Cone erupted between 1675 and 1778, which correlates with the oral history of the Nisga'a, as well as reports that claim an eruption took place during the 18th century.{{sfn|Le Moigne|Vigouroux|Russell|Williams-Jones|2022|p=4}} A [[Common Era]] date of 1690 ± 150 years is provided by the [[Smithsonian Institution]]'s [[Global Volcanism Program]] for the last known eruption of Tseax Cone.{{sfn|Global Volcanism Program: Tseax River Cone|loc=Eruptive History}} The timing of volcanism at Tseax Cone makes it one of the youngest volcanoes in Canada, as well as the site of one of the most recent volcanic eruptions in Canada.{{sfn|Global Volcanism Program: Tseax River Cone|loc=General Information}}{{sfn|Le Moigne|Vigouroux|Russell|Williams-Jones|2022|p=2}}
It has been generally agreed by researchers that the Tseax Cone lava flows were emplaced during a single eruption.{{sfn|Le Moigne|Williams-Jones|Russell|Quane|2020|p=369}}{{sfn|Wuorinen|1978|p=1037}} However, whether the volcano itself is the product of one or more distinct eruptive episodes has been a point of conjecture.{{sfn|Wuorinen|1978|p=1037}}{{sfn|Williams-Jones et al.|2020|p=1248}} In 1923, G. Hanson suggested that Tseax Cone formed during a single eruption. The single eruption hypothesis was also proposed by Sutherland Brown in 1969, but postulated that the volcano was destroyed by explosions and then reformed. In 1978, Vilho Wuorinen provided evidence for Tseax Cone having formed by two distinct eruptive episodes.{{sfn|Wuorinen|1978|pp=1037, 1038}} This included a difference in surface erosion between the external spatter rampart and the inner tephra cone, as well as a difference in vegetation cover between the two structures.{{sfn|Williams-Jones et al.|2020|pp=1242, 1243}} A charred tree trunk found standing in the vertical wall of the spatter rampart also yielded a radiocarbon date of 625 ± 70 years.{{sfn|Williams-Jones et al.|2020|p=1242}} Based on this evidence, Wuorinen proposed that the spatter rampart was formed by an initial period of activity around 1325.{{sfn|Williams-Jones et al.|2020|p=1242}}{{sfn|Wuorinen|1978|p=1037}} This eruptive period was followed by 375 years of dormancy, during which the spatter rampart was smoothed by erosion.{{sfn|Wuorinen|1978|p=1037}} A second eruptive episode around 1700 produced the inner tephra cone, the lava flows and the several smaller satellite cones in the area.{{sfn|Wuorinen|1978|p=1038}}
In 2020, Williams-Jones ''et al.'' reported new [[paleomagnetic]] and [[geochemical]] data supporting the hypothesis that the inner tephra cone, external spatter rampart, satellite cones, lava flows and tephra deposits were all formed during a single period of activity.{{sfn|Williams-Jones et al.|2020|pp=1238, 1247}} However, the charred tree trunk sampled by Wuorinen that yielded a radiocarbon date of 625 ± 70 years was not found during their extensive mapping of the area in 2016 and 2017.{{sfn|Williams-Jones et al.|2020|p=1244}}
===Hazards=== [[File:Lava beds of Nass Valley.jpg|thumb|right|alt=Trees and jagged moss-covered rock reflecting on water in the foreground|Nass Valley lava flow]] The question of whether Tseax Cone formed during one or more distinct eruptive episodes has important implications for future activity and [[volcanic hazard|hazard]] mitigation efforts.{{sfn|Williams-Jones et al.|2020|p=1238}} Renewed activity from Tseax Cone is unlikely if the volcano is [[Monogenetic volcanic field|monogenetic]]; this is because monogenetic volcanoes are typically considered to erupt only once and to be short-lived.{{sfn|Vargas-Arcila et al.|2023|p=1}} If Tseax Cone is [[Polygenetic volcanic field|polygenetic]], future activity could produce lava flows and potentially block local streams as happened previously.{{sfn|Natural Resources Canada: Tseax Cone}}
Damming of the Nass River by lava flows could negatively affect the salmon fisheries on this river. [[Carbon dioxide]] emissions from Tseax Cone could pose a threat to local inhabitants due to the gas's ability to replace oxygen in low-lying areas and poorly ventilated structures. Another potential hazard relating to future activity from Tseax Cone is the ignition of [[wildfire]]s by eruptions since the area contains vegetation.{{sfn|Natural Resources Canada: Tseax Cone}}
==Human history== ===Indigenous peoples=== Tseax Cone is a prominent figure in Nisga'a history and culture due to its association with a [[natural disaster]].{{sfn|Williams-Jones et al.|2020|p=1250}} According to Nisga'a legends, the Tseax Cone eruption caused the deaths of 2,000 people and the destruction of at least three villages on the banks of the Nass River.{{sfn|Williams-Jones et al.|2020|p=1238}}{{sfn|Natural Resources Canada: Tseax Cone}} This would make it the deadliest geological disaster in Canada and the second-worst natural disaster in Canadian history by death toll, exceeded only by the [[1775 Newfoundland hurricane]] which caused at least 4,100 fatalities.{{sfn|Williams-Jones et al.|2020|p=1238}}{{sfn|United States Geological Survey|2021}} Tseax Cone has therefore been described as the deadliest volcano in Canada.{{sfn|Le Moigne|Vigouroux|Russell|Williams-Jones|2022|p=15}} The three Nisga'a villages destroyed by the Tseax Cone eruption have been named [[Lax Ksiluux]], Lax Ksiwihlgest and Wii Lax K'abit.{{sfn|Williams-Jones et al.|2020|p=1238}}{{sfn|BC Geographical Names: Gitwinksihlkw}} Early 19th-century Nisga'a accounts of the eruption were reported by [[anthropologist]] Marius Barbeau in 1935 as follows:
[[File:Detail of a lava bed, Nass Valley.jpg|thumb|right|alt=Rubbly moss-covered lava rock with trees in the background|Detail of lava flow in Nass Valley]] {{blockquote|...the volcanic eruption soon after broke out. First there was smoke, like that coming out of a house, a big pillar of smoke. It was as if a house was burning on the mountain top. The people saw a big fire. The fire came down the side in their direction, but not as fast as forest fire. It moved down slowly, very slowly. It was strange and frightful. It was dangerous! There were fumes spreading ahead, and those who smelled them were smothered. They died and their body stiffened like rock. Frightened, the people of one tribe dug holes in the ground like underground lodges, and hid within, scared as they were of the mountain spirits. Likewise, the other tribe. That did not keep other people from dying of the fumes, mostly in the lower of the villages. As soon as the smoke dispersed some people ran away; a great many others stayed on. They did not suffer any more from the smoke. The fire then rolled down like a river, filled the lake, and for a time the water was a bed of flames. The stone was red and hot there for many days. As far as it went, all the way, it was flowing red. It started from the river where the people fished salmon, away up there, and ran down to the place where the canyon now is...{{sfn|Williams-Jones et al.|2020|p=1250}}}}
The "poisonous smoke" mentioned in Barbeau's report may have been odourless carbon dioxide.{{sfn|Natural Resources Canada: Tseax Cone}} When the first lava flow from Tseax Cone entered the [[Nass Valley]], it destroyed the three Nisga'a villages. Interaction of the lava flow with the Nass River may have produced dense clouds of vaporized water mixed with [[volcanic gas]]es such as carbon dioxide and [[hydrogen sulfide]]. [[Methane]] may have also been released from [[wetland]]s as the lava flow travelled over the Nass River floodplain.{{sfn|Le Moigne|2020|p=105}} While some of the Nisga'a may have escaped the lava flow by canoe to the far side of the Nass River, many of them were caught between the river and the advancing lava flow. The average discharge rate of the Nass River is strong enough to drown anyone attempting to escape by swimming during the summer months of June, August and September; Tseax Cone is suspected to have erupted during this time.{{sfn|Le Moigne|2020|p=104}} Another hypothesis is that as the lava flow entered the Nass River, it caused sudden waves and turbulence which swept away the Nisga'a paddling across the river.{{sfn|Hickson et al.|2007}}
The Nisga'a also recall the disruption of the Tseax River, stating that "before the volcanic eruption, when our people lived here at Wii Lax K'ap, there was a stream close by where salmon spawned. The stream bed had white sand and they could easily spot the salmon going up stream. This stream was thus named Ksi Gimwits'ax. Years later [after the volcanic eruption] when this stream resurfaced, and though the Nisga'a knew it was the same tributary, it was renamed Ksi Sii Aks."{{sfn|BC Geographical Names: Ksi Sii Aks}} A [[salamander]] species that once inhabited the bay area of Gitwinksihlkw on the Nass River is said to have disappeared or became extinct following the eruption.{{sfn|BC Geographical Names: Gitwinksihlkw}}
===Provincial park=== Pleas for protection of the Tseax Cone lava flows date back to at least 1972 when forestry operations had left tree stumps and debris on their surfaces.{{sfn|Gentles|1972|pp=251, 252}} Roads and trails had also been established on the lava flows by this time; their terrain is ideal for road construction due to their fragility. The lava was also being excavated from [[borrow pit]]s and hauled to be used on forest service roads.{{sfn|Gentles|1972|p=252}} It was not until 1992 when [[Nisga'a Memorial Lava Bed Provincial Park]] was founded to preserve the volcanic landscape and to honour the 2,000 Nisga'a people who died during the Tseax Cone eruption.{{sfn|Natural Resources Canada: Tseax Cone}}{{sfn|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}} This {{Convert|17717|ha|adj=mid|abbr=off}} [[protected area]] is noteworthy for being the first [[List of British Columbia Provincial Parks|provincial park in British Columbia]] to be managed by both [[BC Parks]] and a [[First Nations in Canada|First Nation]], as well as the first provincial park in British Columbia to combine indigenous culture and natural features.{{sfn|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}}
==Accessibility== The Tseax Cone lava flows are most easily accessed by travelling the [[Nisga'a Highway]] north of Terrace for {{Convert|100|km|mi|abbr=on}}, the final {{Convert|30|km|mi|abbr=on}} of which is unpaved. An alternative route to the lava flows involves travelling the paved [[Stewart–Cassiar Highway]] north of [[Kitwanga]] for {{Convert|78|km|mi|abbr=on}} to the Cranberry River.{{sfn|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}} From there, the unpaved Nass Forest Service Road extends {{Convert|86|km|mi|abbr=on}} southwest to Gitlaxt'aamiks which lies on the northeastern edge of the lava flows.{{sfn|Williams-Jones et al.|2020|p=1239}}{{sfn|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}} Access to Tseax Cone is limited only to a {{Convert|6|km|mi|abbr=on}} long guided hiking tour from an access road {{Convert|1.4|km|mi|abbr=on}} north of the Lava Lake picnic site on the Nisga'a Highway.{{sfn|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}}
==See also== {{Portal|Volcanoes|Mountains}} *[[List of disasters in Canada by death toll]] *[[List of volcanic eruptions by death toll]] *[[List of Northern Cordilleran volcanoes]] *[[List of volcanoes in Canada]] *[[Volcanism of Western Canada]]
==Notes== {{notelist}}
==References== {{reflist}}
===Sources=== {{refbegin|30em}} *{{cite book|last1=Akrigg|first1=G. P. V.|last2=Akrigg|first2=Helen B.|title=British Columbia Place Names|publisher=[[University of British Columbia Press]]|year=1997|edition=3rd|isbn=0-7748-0636-2}} *{{cite web|title=Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]|publisher=[[BC Parks]]|url=https://bcparks.ca/anhluutukwsim-laxmihl-angwingaasanskwhl-nisgaa-park-aka-nisgaa-memorial-lava-bed-park/|archive-url=https://web.archive.org/web/20240804061301/https://bcparks.ca/anhluutukwsim-laxmihl-angwingaasanskwhl-nisgaa-park-aka-nisgaa-memorial-lava-bed-park/#park-overview-container|archive-date=August 4, 2024|ref={{harvid|BC Parks: Anhluut'ukwsim Lax̱mihl Angwinga'asanakwhl Nisga'a [a.k.a. Nisga'a Memorial Lava Bed Park]}}}} *{{cite bcgnis|id=41229|name=Cassiar Land District|archive-url=https://web.archive.org/web/20180627144631/http://apps.gov.bc.ca/pub/bcgnws/names/41229.html|archive-date=June 27, 2018|ref={{harvid|BC Geographical Names: Cassiar Land District}}}} *{{cite bcgnis|id=37116|name=Crater Creek|archive-url=https://web.archive.org/web/20211126194227/https://apps.gov.bc.ca/pub/bcgnws/names/37116.html|archive-date=November 26, 2021|ref={{harvid|BC Geographical Names: Crater Creek}}}} *{{cite book|last1=Demarchi|first1=Dennis A.|title=An Introduction to the Ecoregions of British Columbia|publisher=[[Government of British Columbia]]|year=2011|oclc=613357103}} *{{cite report|last1=Denton|first1=George H.|url=https://books.google.com/books?id=5TtRAAAAMAAJ|title=Mountain Glaciers of the Northern Hemisphere|publisher=[[Cold Regions Research and Engineering Laboratory]]|chapter=Glaciers of the Interior Ranges of British Columbia|volume=1|pages=655–670|year=1975}} *{{cite book|title=Dictionary of Geology and Mineralogy|year=2003|publisher=[[McGraw Hill]]|isbn=0-07-141044-9|ref={{harvid|McGraw Hill|2003}}}} *{{cite journal|title=Distribution, Nature, and Origin of Neogene–Quaternary Magmatism in the Northern Cordilleran Volcanic Province, Canada|last1=Edwards|first1=Benjamin R.|last2=Russell|first2=James K.|journal=[[Geological Society of America Bulletin]]|publisher=[[Geological Society of America]]|pages=1280–1295|volume=112|issue=8|year=2000|issn=0016-7606|doi=10.1130/0016-7606(2000)112<1280:dnaoon>2.0.co;2|bibcode=2000GSAB..112.1280E}} *{{cite journal|last1=Gentles|first1=T.|journal=The Blue Jay|title=Pleas for Protection of Aiyansh Lava Flow|issue=4|volume=30|year=1972|publisher=Saskatchewan Natural History Society|doi=10.29173/bluejay3508|issn=0006-5099|doi-access=free}} *{{cite bcgnis|id=39898|name=Gitwinksihlkw|archive-url=https://web.archive.org/web/20200218012814/http://apps.gov.bc.ca/pub/bcgnws/names/39898.html|archive-date=February 18, 2020|ref={{harvid|BC Geographical Names: Gitwinksihlkw}}}} *{{cite web|last1=Hickson|first1=C. J.|last2=Spurgeon|first2=T. C.|last3=Cocking|first3=R. B.|last4=Russel|first4=J. K.|last5=Woodsworth|first5=G. J.|last6=Ulmi|first6=M.|last7=Rust|first7=A. C.|url=https://gsa.confex.com/gsa/2007CD/webprogram/Paper121306.html|title=Tseax Volcano: A Deadly Basaltic Eruption in North-Western British Columbia, Canada|publisher=[[Geological Society of America]]|year=2007|archive-url=https://web.archive.org/web/20230604050853/https://gsa.confex.com/gsa/2007CD/webprogram/Paper121306.html|archive-date=2023-06-04|ref={{harvid|Hickson et al.|2007}}}} *{{cite journal|last1=Higgins|first1=Michael D.|title=The Cascadia Megathrust Earthquake of 1700 May Have Rejuvenated an Isolated Basalt Volcano in Western Canada: Age and Petrographic Evidence|journal=[[Journal of Volcanology and Geothermal Research]]|publisher=[[Elsevier]]|pages=149–156|volume=179|year=2009|issue=1|doi=10.1016/j.jvolgeores.2008.10.016|bibcode=2009JVGR..179..149H|issn=0377-0273}} *{{cite bcgnis|id=54016|name=Ksi Sii Aks|archive-url=https://web.archive.org/web/20211127133124/https://apps.gov.bc.ca/pub/bcgnws/names/54016.html|archive-date=November 27, 2021|ref={{harvid|BC Geographical Names: Ksi Sii Aks}}}} *{{cite web|publisher=[[Postmedia Network]]|url=https://o.canada.com/travel/lava-beds-and-other-reasons-to-love-northern-british-columbia|title=Lava Beds and Other Reasons to Love Northern British Columbia|work=canada |date=November 6, 2019|archive-date=April 21, 2021|archive-url=https://web.archive.org/web/20210421144443/https://o.canada.com/travel/lava-beds-and-other-reasons-to-love-northern-british-columbia|ref={{harvid|Postmedia Network|2019}}}} *{{cite thesis|last=Le Moigne|first=Yannick|url=https://theses.hal.science/tel-03244605v1/document|title=Investigating Canada's Deadliest Volcanic Eruption and Mitigating Future Hazards|publisher=[[Simon Fraser University]]|year=2020|degree=PhD|access-date=December 17, 2025}} *{{cite journal|last1=Le Moigne|first1=Y.|last2=Vigouroux|first2=N.|last3=Russell|first3=J.K.|last4=Williams-Jones|first4=G.|title=Magmatic Origins and Storage Conditions for the Historic Eruption of Tseax Volcano, British Columbia, Canada|journal=[[Chemical Geology]]|publisher=[[Elsevier]]|pages=1–18|volume=588|year=2022|article-number=120648 |doi=10.1016/j.chemgeo.2021.120648|bibcode=2022ChGeo.58820648L |issn=0009-2541}} *{{cite journal|last1=Le Moigne|first1=Yannick|last2=Williams-Jones|first2=Glyn|last3=Russell|first3=Kelly|last4=Quane|first4=Steve|title=Physical Volcanology of Tseax Volcano, British Columbia, Canada|journal=[[Journal of Maps]]|publisher=[[Taylor & Francis]]|pages=363–375|volume=16|issue=2|year=2020|issn=1744-5647|doi=10.1080/17445647.2020.1758809|bibcode=2020JMaps..16..363L |s2cid=219495677 |doi-access=free|hdl=10.1080/17445647.2020.1758809|hdl-access=free}} *{{cite journal|last1=Le Moigne|first1=Yannick|last2=Williams-Jones|first2=Glyn|last3=Vigouroux|first3=Nathalie|last4=Kelly Russell|first4=James|title=Chronology and Eruption Dynamics of the Historic∼1700 CE Eruption of Tseax Volcano, British Columbia, Canada|journal=[[Frontiers in Earth Science]]|publisher=[[Frontiers Media]]|pages=1–20|volume=10|year=2022|article-number=910451 |issn=2296-6463|doi=10.3389/feart.2022.910451|bibcode=2022FrEaS..10.0451L|doi-access=free|ref={{harvid|Le Moigne et al.|2022}}}} *{{cite journal|last1=Marshall|first1=Peter|url=https://www.tandfonline.com/doi/abs/10.1080/00040851.1975.12003851|title=Ice-Blocked Tubes in the Aiyansh Flow, British Columbia|journal=[[Arctic and Alpine Research]]|publisher=[[Institute of Arctic and Alpine Research]]|pages=399–400|volume=7|issue=4|year=1975|doi=10.1080/00040851.1975.12003851|url-access=subscription}} *{{cite bcgnis|id=36153|name=Melita Lake|archive-url=https://web.archive.org/web/20211126195726/https://apps.gov.bc.ca/pub/bcgnws/names/36153.html|archive-date=November 26, 2021|ref={{harvid|BC Geographical Names: Melita Lake}}}} *{{cite bcgnis|id=36874|name=New Aiyansh|access-date=March 16, 2025|ref={{harvid|BC Geographical Names: New Aiyansh}}}} *{{cite journal|last1=Osman|first1=Sara|last2=Jones|first2=Thomas J.|last3=McCartney|first3=Kelly N.|last4=Moigne|first4=Yannick Le|last5=Russell|first5=James K.|last6=Williams-Jones|first6=Glyn|title=The Volume of Explosive Products Erupted During the ~1700 CE Eruption of ''Sii Aks'' (Tseax), Canada|journal=[[Bulletin of Volcanology]]|publisher=[[Springer Science+Business Media]]|pages=1–10|volume=88|issue=18|year=2026|doi=10.1007/s00445-026-01941-5|s2cid=285074508|issn=0258-8900|doi-access=free|ref={{harvid| Osman et al.|2026}}}} *{{cite encyclopedia|last=Pinti|first=Daniele|year=2011|encyclopedia=Encyclopedia of Astrobiology|publisher=[[Springer Berlin Heidelberg]]|doi=10.1007/978-3-642-11274-4_1893|isbn=978-3-642-11271-3|chapter=Mafic and Felsic|page=938 }} *{{cite web|publisher=[[Government of British Columbia]]|url=https://engage.gov.bc.ca/bcparksblog/2019/11/14/fires-and-floods-at-nisgaa-memorial-lava-bed-park/|title=Researchers Investigate how Vegetation is Changing at Nisga'a Memorial Lava Bed Park|date=November 14, 2019|archive-url=https://web.archive.org/web/20230608162340/https://engage.gov.bc.ca/bcparksblog/2019/11/14/fires-and-floods-at-nisgaa-memorial-lava-bed-park/|archive-date=June 8, 2023|ref={{harvid|Government of British Columbia}}}} *{{cite journal|last1=Roberts|first1=Michael C.|last2=McCuaig|first2=Shirley J.|title=Geomorphic Responses to the Sudden Blocking of a Fluvial System: Aiyansh Lava Flow, Northwest British Columbia|journal=[[The Canadian Geographer]]|publisher=[[Canadian Association of Geographers]]|pages=319–323|volume=45|issue=2|year=2001|doi=10.1111/j.1541-0064.2001.tb01492.x|bibcode=2001CGeog..45..319R |issn=0008-3658}} *{{cite bcgnis|id=38278|name=Ross Lake|access-date=February 6, 2025|ref={{harvid|BC Geographical Names: Ross Lake}}}} *{{cite book|last=Slaymaker|first=Olav|title=Landscapes and Landforms of Western Canada|publisher=[[Springer International Publishing]]|year=2017|isbn=978-3-319-44593-9}} *{{cite book|editor-last1=Etkin|editor-first1=David|editor-last2=Haque|editor-first2=C. E.|editor-link2=C. Emdad Haque|editor-last3=Brooks|editor-first3=Gregory R.|last1=Stasiuk|first1=Mark V.|last2=Hickson|first2=Catherine J.|author-link2=Catherine Hickson|last3=Mulder|first3=Taimi|title=An Assessment of Natural Hazards and Disasters in Canada|chapter=The Vulnerability of Canada to Volcanic Hazards|publisher=[[Kluwer Academic Publishers]]|date=2003|pages=563–589|isbn=1-4020-1179-2}} *{{cite journal|last1=Symons|first1=D. T. A.|title=Age and Flow Direction from Magnetic Measurements on the Historic Aiyansh Flow, British Columbia|journal=[[Journal of Geophysical Research]]|publisher=[[American Geophysical Union]]|pages=2622–2626|volume=80|year=1975|issue=17|doi=10.1029/JB080i017p02622|bibcode=1975JGR....80.2622S |issn=0148-0227}} *{{cite bcgnis|id=40915|name=Tseax Cone|archive-url=https://web.archive.org/web/20241201154422/https://apps.gov.bc.ca/pub/bcgnws/names/40915.html|archive-date=December 1, 2024|ref={{harvid|BC Geographical Names: Tseax Cone}}}} *{{cite web|publisher=[[Natural Resources Canada]]|url=http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tsx_107|title=Tseax Cone|work=Catalogue of Canadian Volcanoes|date=August 19, 2005|url-status=dead|archive-url=https://web.archive.org/web/20080111031918/http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_tsx_107|archive-date=January 11, 2008|ref={{harvid|Natural Resources Canada: Tseax Cone}}}} *{{cite cgndb|id=JDDHM|title=Tseax Cone|access-date=October 6, 2023|ref={{harvid|Geographical Names Data Base: Tseax Cone}}}} *{{cite gvp|title=Tseax River Cone|vn=320100|archive-date=October 29, 2021|ref={{harvid|Global Volcanism Program: Tseax River Cone}}|url-status=live}} *{{cite web|last1=Turner|first1=Bob|last2=Nelson|first2=JoAnne|last3=Franklin|first3=Richard|last4=Weary|first4=Gordon|last5=Walker|first5=Tony|last6=Hayward|first6=Bonnie|last7=McRae|first7=Cathy|title=GeoTour Guide for Terrace, B.C.: Our Land, Our Community.|publisher=British Columbia Geological Survey|url=https://www.llbc.leg.bc.ca/public/PubDocs/bcdocs/410106/Terrace-GeoTour.pdf|archive-url=https://web.archive.org/web/20240629165452/https://www.llbc.leg.bc.ca/public/PubDocs/bcdocs/410106/Terrace-GeoTour.pdf|archive-date=June 29, 2024|series=Geofile 2007–10|year=2007|ref={{harvid|Turner et al.|2007}}}} *{{cite web|url=https://volcanoes.usgs.gov/vsc/glossary.html|archive-url=https://web.archive.org/web/20231127231846/https://volcanoes.usgs.gov/vsc/glossary.html|title=USGS Volcano Hazards Program Glossary|publisher=[[United States Geological Survey]]|year=2018|archive-date=November 27, 2023|ref={{harvid|United States Geological Survey|2018}}}} *{{cite journal|last1=Vargas-Arcila|first1=Laura|last2=Murcia|first2=Hugo|last3=Osorio-Ocampo|first3=Susana|last4=Sánchez-Torres|first4=Laura|last5=Botero-Gómez|first5=Luis Alvaro|last6=Bolaños|first6=Gina|title=Effusive and Evolved Monogenetic Volcanoes: Two Newly Identified (~800 ka) Cases Near Manizales City, Colombia|journal=[[Bulletin of Volcanology]]|publisher=[[Springer Science+Business Media]]|pages=1–13|volume=85|issue=42|year=2023|doi=10.1007/s00445-023-01655-y|bibcode=2023BVol...85...42V|s2cid=259277907|issn=0258-8900|doi-access=free|ref={{harvid|Vargas-Arcila et al.|2023}}}} *{{cite bcgnis|id=38278|name=Vetter Creek|access-date=February 5, 2025|ref={{harvid|BC Geographical Names: Vetter Creek}}}} *{{cite web|url=http://www.usgs.gov/news/volcano-watch-volcanoes-canada-eh|title=Volcano Watch — Volcanoes in Canada, eh?|date=July 1, 2021|archive-date=November 3, 2022|archive-url=https://web.archive.org/web/20221103015731/http://www.usgs.gov/news/volcano-watch-volcanoes-canada-eh|publisher=[[United States Geological Survey]]|ref={{harvid|United States Geological Survey|2021}}}} *{{cite journal|last1=Williams-Jones|first1=Glyn|last2=Barendregt|first2=René W.|last3=Russell|first3=James K|last4=Le Moigne|first4=Yannick|last5=Enkin|first5=Randolph J.|last6=Gallo|first6=Rose|title=The Age of the Tseax Volcanic Eruption, British Columbia, Canada|journal=[[Canadian Journal of Earth Sciences]]|publisher=[[Canadian Science Publishing]]|pages=1238–1253|volume=57|issue=10|year=2020|doi=10.1139/cjes-2019-0240 |bibcode=2020CaJES..57.1238W|s2cid=216209167|issn=1480-3313|ref={{harvid|Williams-Jones et al.|2020}}}} *{{cite journal|last=Wuorinen|first=Vilho|title=Age of Aiyansh Volcano, British Columbia|journal=[[Canadian Journal of Earth Sciences]]|publisher=[[NRC Research Press]]|pages=1037–1038|volume=15|issue=6|year=1978|doi=10.1139/e78-111|bibcode=1978CaJES..15.1037W}} {{refend}}
==External links== *{{commons category-inline|Tseax Cone}} *{{cite web|url=https://www.cbc.ca/news/canada/british-columbia/tseax-volcano-map-1.5605111|title=Nisga'a Knowledge Helps Scientists Create First Detailed map of Tseax Volcano|publisher=[[Canadian Broadcasting Corporation]]|date=June 9, 2020}} *{{cite web|url=https://www.terracestandard.com/news/scientists-produce-extensive-map-of-tseax-volcano-lava-flow/|title=Scientists produce extensive map of Tseax Volcano, Lava Flow|publisher=Terrace Standard and Black Press Group|date=June 3, 2020}} *{{cite web|url=https://www.canadiana.ca/view/oocihm.15537/9|title=Ignis: a Parable of the Great Lava Plain in the Valley of "Eternal Bloom", Naas River, British Columbia}}
{{Northern Cordilleran volcanoes}} {{Interior Mountains}}
[[Category:Cinder cones of British Columbia]] [[Category:Rift volcanoes]] [[Category:Natural disasters in British Columbia]] [[Category:Nass Country]] [[Category:Nisga'a]] [[Category:Northern Cordilleran Volcanic Province]] [[Category:18th-century volcanic events]] [[Category:Hazelton Mountains]] [[Category:VEI-2 volcanoes]] [[Category:Holocene British Columbia]] [[Category:Caves of British Columbia]]