| Exile Hill | |
|---|---|
| Exile Peak | |
 Geologicalcross section of Exile Hill | |
| Highest point | |
| Elevation | 1,890 m (6,200 ft)[1] |
| Coordinates | 57°22′41″N130°49′29″W / 57.37806°N 130.82472°W /57.37806; -130.82472[2] |
| Geography | |
  Exile Hill Location in British Columbia | |
 | |
| Location inMount Edziza Provincial Park | |
| Country | Canada[3] |
| Province | British Columbia[3] |
| District | Cassiar Land District[2] |
| Protected area | Mount Edziza Provincial Park[2] |
| Parent range | Tahltan Highland[3] |
| Topo map | NTS 104G7Mess Lake[2] |
| Geology | |
| Formed by | Volcanism[4] |
| Mountain type(s) | Cinder cone,plug dome[5][6] |
| Rock type(s) | Basalt,trachyte[7] |
| Last eruption | Pliocene age[5] |
Exile Hill, sometimes referred to asExile Peak, is an isolated hill inCassiar Land District of northwesternBritish Columbia, Canada. It has anelevation of 1,890 metres (6,200 feet) and is part of theArctic Lake Plateau or the neighbouringSpectrum Range, which are within the limits of theTahltan Highland. Exile Hill is about 60 kilometres (37 miles) southeast of the community ofTelegraph Creek inMount Edziza Provincial Park. Access to Exile Hill is via aircraft, which are permitted to land onMess Lake and Little Arctic Lake to the northwest and southeast, respectively.
Exile Hill is part of theMount Edziza volcanic complex, which consists of diverse landforms such asshield volcanoes,stratovolcanoes,lava domes andcinder cones. Thevolcanic rocks comprising the hill are ofPliocene age and are subdivided into twogeological formations that were deposited during thesecond magmatic cycle of the Mount Edziza volcanic complex.Basalt comprises theNido Formation whereas the younger Spectrum Formation consists oftrachyte. Nearby volcanic features includeOutcast Hill,Tadekho Hill,Kuno Peak,Nahta Cone andWetalth Ridge.
The name of the hill became official on January 2, 1980, and was adopted on theNational Topographic System map 104G/15 after being submitted to theBC Geographical Names office by theGeological Survey of Canada.[2][8]Exile is a reference to the Wetalth, a group of seven people previously living in the area who were outcast or exiled from theTahltans.[2][9]Nahta Cone,Outcast Hill andWetalth Ridge are extensions of the Wetalth theme.[10] CanadianvolcanologistJack Souther labelled Exile Hill asExile Peak on ageological map in his 1992 report,The Late Cenozoic Mount Edziza Volcanic Complex, British Columbia.[11]
Exile Hill is located about 60 km (37 mi) southeast of the community ofTelegraph Creek inCassiar Land District of northwesternBritish Columbia, Canada.[2][3][12] It has anelevation of 1,890 m (6,200 ft) and is part of theArctic Lake Plateau or the neighbouringSpectrum Range, which are at the southern end of theMount Edziza volcanic complex.[1][2][3][13] The volcanic complex consists of a group of overlappingshield volcanoes,stratovolcanoes,lava domes andcinder cones that have formed over the last 7.5 million years.[14] Exile Hill rises above the southeastern side ofMess Creek valley and istopographically higher than its surroundings.[3][15] Theterrain east of Exile Hill is relatively flat, but elsewhere it is surrounded by vegetated valleys.[3]Tadekho Creek and Nahta Creek flow through valleys north and south of Exile Hill, respectively, and aretributaries of Mess Creek.[3][16]
Exile Hill is surrounded by a number of other landforms within the Mount Edziza volcanic complex.[16] Outcast Hill, about 5 km (3.1 mi) to the northeast, is a cinder cone on aninterfluve between Tadekho Creek to the south and an unnamed tributary of Tadekho Creek to the north.[3][17] About 5 km (3.1 mi) southeast of Exile Hill isTadekho Hill, a nearly circularvolcanic cone about 5 km (3.1 mi) northwest of Little Arctic Lake.[3][18]Kuno Peak, about 10 km (6.2 mi) to the east, is a glaciated mountain peak at the western end of aridge extending from the southwestern end of the Spectrum Range.[3] About 10 km (6.2 mi) south and southeast of Exile Hill are Nahta Cone and Wetalth Ridge, respectively, which are on the opposite side of Nahta Creek valley.[3][16]
Exile Hill lies inMount Edziza Provincial Park which, with an area of 266,180 hectares (657,700 acres), is one of the largestprovincial parks in British Columbia.[2][19][20] It was established in 1972 to preserve the volcanic landscape extending fromMount Edziza in the north to the Spectrum Range in the south.[3][20] Mount Edziza Provincial Park is in theTahltan Highland, a southeast-trendingupland area extending along the western side of theStikine Plateau.[3][21]
As a part of the Mount Edziza volcanic complex, Exile Hill lies within a broad area of volcanoes and lava flows called theNorthern Cordilleran Volcanic Province, which extends from northwestern British Columbia northwards throughYukon into easternmostAlaska.[16][22] The dominant rocks comprising these volcanoes arealkali basalts andhawaiites, butnephelinite,basanite andperalkaline[a]phonolite,trachyte andcomendite are locally abundant. These rocks were deposited by volcanic eruptions from 20 million years ago to as recently as a few hundred years ago. The cause of volcanic activity in the Northern Cordilleran Volcanic Province is thought to be due torifting of theNorth American Cordillera, driven by changes in relativeplate motion between theNorth American andPacific plates.[24]
Exile Hill consists ofPliocenevolcanic rocks that comprise twogeological formations, both of which were deposited by volcanic eruptions during thesecond magmatic cycle of the Mount Edziza volcanic complex.[16][25] The oldest geological formation, the 4.4-million-year-oldNido Formation, is subdivided into twogeological members; the Kounugu Member is the main geological member at Exile Hill.[16][26]Alkali basalt, hawaiite andpicrite are the main rocks comprising the Kounugu Member, which erupted from at least four separate eruptive centres: Swarm Peak, Vanished Peak, Lost Peak and Exile Hill.[16][27] The youngest geological formation, the 3.1-million-year-old Spectrum Formation, comprises mostlycomendite,pantellerite and pantelleritictrachyte that erupted from theSpectrum Dome and much smallersatellitic centres such as Exile Hill.[7][16] Exile Hill is the only eruptive centre of the Mount Edziza volcanic complex known to have been active during both theNido andSpectrum eruptive periods, but the amount of lava erupted from it remains unknown.[28]
The formation of Exile Hill began with the eruption of a smallcinder cone on the extreme western edge of the surrounding plateau.[5][29] This cone was almost completely inundated by younger lava flows from the south and east, but thick deposits ofbombs and agglutinatedspatter exposed on the southeastern flank of Exile Hill are probably remnants of this early cone.[30] A series ofbasaltic lava flows up to 180 m (590 ft) thick, believed to have originated from a vent adjacent to Exile Hill, are exposed in isolatedbuttes and in cliffs along the upper Mess Creek valley.[31]
Basaltic lava flows of Exile Hill aregeomorphologically and compositionally more diverse than those from the Swarm Peak and Vanished Peak eruptive centres. The lowermost basaltic lava flow forming the base of Exile Hill is more than 30 m (98 ft) thick whereas the uppermost rubbly basaltic lava flows are only a few metres in thickness. Characterizing the lowermost basaltic lava flows are long, curving columns that occur in sheath-like clusters. In contrast, the upper basaltic lava flows contain random, blockycolumnar jointing or stout, spheroidally weathered columns.[31]
Exile Hill basalt is overlain by a thick layer of gravel that consists mainly of pebbles andcobblestones. The pebbles and cobblestones consist ofrhyolite andobsidian, which probably originated from the Spectrum Dome to the east. Jack Souther mapped the gravel as part of the Nido Formation in 1992.[6]
The western side of Exile Hill contains a smallplug dome of Spectrum Formation trachyte about 100 m (330 ft) high that was formed during at least three separate lava eruptions.[32] This 213 m (699 ft) wide dome contains prominent vertical flow layering and is surrounded bybreccia that protrudes through the Nido Formation basalt.[32] The breccia was deposited by anexplosive eruption and consists of immensely altered, rusty trachyteclasts[b] in a yellowish-browngroundmass of much smaller breccia particles.[7]Yeda Peak about 8 km (5.0 mi) east of Exile Hill was the site of a similar but much larger eruption near the end of the Spectrum eruptive period.[34]
A roughly 100 m (330 ft) thick series of trachyte lava flows caps the summit of Exile Hill and overlies the thick layer of gravel capping the Nido Formation basalt. The trachyte is fine grained, pantelleritic in composition and contains 1–2 mm (0.039–0.079 in) widephenocrysts offeldspar.Interlayering these lava flows arebeds ofpyroclastic material containing bombs, spatter and light-coloured trachyteblocks that have beenfused together.[6]
Exposed on the southwestern side of Exile Hill is a small porous green trachyteintrusion underlying the breccia. It is irregular in mass and contains subhorizontal flow layering, suggesting that thissubvolcanic intrusion most likely formed when trachyticmagma moved laterally from the dome conduit and crystallized into the surrounding Nido Formation basalt.[32]
Exile Hill is underlain bymetasedimentary rocks of theStikiniaterrane, aPaleozoic andMesozoicsuite ofvolcanic andsedimentary rocks thataccreted[c] to thecontinental margin of North America during theJurassic.[16][36][37] Most of these rocks around the base of Exile Hill are covered withfelsenmeer,till, glacial outwash,fluvial outwash orsolifluction deposits. The northwestern side of Exile Hill contains activetalus cones whereas the southwestern and northeastern sides of the hill contain landslide deposits which extend onto thebasement rocks.[16]
As of 2025, Alpine Lakes Air and BC Yukon Air are the only air charter companies permitted to provide access to this area via aircraft.[20] Private aircraft are also permitted to land in the area, but a letter of authorization from theBC Parks Stikine Senior Park Ranger is required to land onMess Lake and Little Arctic Lake, which are the closest lakes of significant size to Exile Hill.[3][20] These two lakes are about 10 and 7 km (6.2 and 4.3 mi) northwest and southeast of Exile Hill, respectively.[3]
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