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Big Raven Plateau
Lava plateau
An overhead view of a barren, rocky plateau with a glaciated mountain in the middle.
Satellite image of the Big Raven Plateau
Big Raven Plateau is located in British Columbia
Big Raven Plateau
Big Raven Plateau
Location in British Columbia
Coordinates: 57°42′49″N 130°45′06″W / 57.71361°N 130.75167°W / 57.71361; -130.75167[1]
LocationBritish Columbia, Canada[2]
RangeTahltan Highland[2]
Part ofMount Edziza complex[3]
Age7.5 million years and younger[4]
Formed byVolcanic activity[4]
GeologyTrachybasalt, trachyte, hawaiite, tristanite, mugearite, comendite, benmoreite, pantellerite, alkali basalt[5]
Last eruptionLess than 2,000 years ago[6]
Topo mapNTS 104G10 Mount Edziza[1]
DesignationMount Edziza Provincial Park[2]
Borders onChakima Creek valley (south)[2]
Walkout Creek valley (south)[2]
Klastline River valley (north)[2]
Kakiddi Creek valley (east)[2]
Mess Creek valley (west)[2]
Map Location in Mount Edziza Provincial Park

The Big Raven Plateau is a lava plateau in Cassiar Land District of northwestern British Columbia, Canada.












Geography and geomorphology

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Location

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The Big Raven Plateau is on the Tahltan Highland east of the Zagoddetchino massif and west of the Klastline Plateau in Cassiar Land District. Between the Zagoddetchino massif and the Big Raven Plateau is Mess Creek valley which extends more than 60 kilometres (37 miles) to the south where it separates the Boundary Ranges of the Coast Mountains in the west from the Spectrum Range and Arctic Lake Plateau in the east. Between the Big Raven and Klastline plateaus is the north–south trending Kakiddi Creek valley which includes a number small lakes such as Nuttlude Lake, Kakiddi Lake, Mowchilla Lake and Mowdade Lake. The northern end of the Big Raven Plateau is bounded by the Klastline River valley while the southern end is bounded by two relatively small east–west trending valleys; a mountain ridge extends south of the Big Raven Plateau between these valleys.[2]

The Big Raven Plateau lies at the northern end of the Mount Edziza volcanic complex which also includes the Arctic Lake and Kitsu plateaus, as well as the Spectrum Range to the south.[3] This volcanic complex consists of a group of overlapping shield volcanoes, stratovolcanoes, lava domes and cinder cones that have formed over the last 7.5 million years. It contains four central volcanoes along its north–south trending axis; from north to south these are Mount Edziza, Ice Peak, Armadillo Peak and the Spectrum Range.[4]

Drainage

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As a part of the Mount Edziza volcanic complex, the Big Raven Plateau is drained entirely by streams within the Stikine River watershed.[2][7] The northeastern portion of the Big Raven Plateau is drained by Tsecha Creek which flows to the northeast.[2] Draining the eastern side of the plateau are a series of east-flowing streams choaked with glacial and landslide debris from rapidly eroding headwalls; from north to south these are Tenchen Creek, Nido Creek, Tennaya Creek, Sorcery Creek and Shaman Creek.[2][8] Transportation of the glacial and landslide debris into Kakiddi Creek valley has resulted in the formation of several large alluvial fans behind which Nuttlude Lake, Kakiddi Lake, Mowdade Lake and Mowchilla Lake have ponded.[8] Nido Creek and Tennaya Creek flow into Nuttlude Lake while Sorcery Creek and Shaman Creek flow into Kakiddi Lake.[2] Both lakes are expansions of Kakiddi Creek which flows north into the Klastline River, a tributary of the Stikine River.[2][9][10]

Elwyn Creek and its tributary, Kadeya Creek, drain the northwestern portion of the plateau; Elwyn Creek flows westward while Kadeya Creek flows to the northwest.[2][11] Northwest-flowing Taweh Creek and its tributary, the westward-flowing Sezill Creek, drain the southwestern and western portions of the plateau, respectively.[2][12][13] Elwyn Creek and Taweh Creek are tributaries of Mess Creek which flows northwestward into the Stikine River.[2][14] The northern end of the Big Raven Plateau is drained by small, unnamed streams which flow north into the Klastline River; these streams are shallowly incised into the plateau.[2][8] At the southern end of the Big Raven Plateau is a drainage divide between Chakima Creek, flowing east into the Kakiddi drainage and Walkout Creek flowing west, via Raspberry Creek into Mess Creek.[2][15]

Structure

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The Big Raven Plateau is roughly oval in structure and relatively barren of vegetation which contrasts with the surrounding valleys.[2] In contrast to the northern end of the plateau which is relatively smooth and uneroded, the eastern side has undergone extensive erosion which has resulted in the creation of steep spurs with intervening valleys.[2][8] A handful of these spurs are named on the southeastern side of the Big Raven Plateau; from north to south they are Idiji Ridge, Sorcery Ridge and Cartoona Ridge. Idiji Ridge extends east from the northern end of Tencho Glacier and is the namesake of Idiji Glacier which exists to the northwest. Sorcery Ridge, which shares its name with adjacent Sorcery Creek, extends east from the southern end of Tencho Glacier. Cartoona Ridge lies between Chakima and Shaman creek valleys and shares its name with Cartoona Peak at the westernmost end of the ridge.[5]

The western side of the Big Raven Plateau has been moderately dissected by stream erosion which has resulted in the formation of steep-sided canyons; Elwyn, Sezill and Taweh creek canyons are the most extensive.[2][8] Elwyn and Sezill creek canyons contain hot springs with recorded water temperatures of 36 degrees Celsius (97 degrees Fahrenheit) and 46 degrees Celsius (115 degrees Fahrenheit), respectively. Discharge at these hot springs may be linked to shallow hydrothermal systems driven by residual magmatic heat as they are adjacent to recently active volcanic centres on the plateau.[5][16] Forming the southwestern boundary of the Big Raven Plateau is the Mess Creek Escarpment which extends at least 25 kilometres (16 miles) to the south where it forms the western boundary of the Kitsu Plateau.[2][3]

Landforms

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The summit crater of Mount Edziza

The Big Raven Plateau is dominated by the ice-covered stratovolcano of Mount Edziza which rises to an elevation of 2,786 metres (9,140 feet) from the middle of the plateau.[2][17][18] Immediately north of Mount Edziza is the Desolation Lava Field which covers an area of more than 150 square kilometres (58 square miles) and mostly issued from cinder cones near the northern trim line of Mount Edziza's ice cap.[19] The Snowshoe Lava Field immediately southwest of Mount Edziza covers an area of about 40 square kilometres (15 square miles) and mostly issued from cones on the southwestern flank of Ice Peak.[20]

Smaller features on the Big Raven Plateau include Hoia Bluff at the southwestern end of the plateau along Taweh Creek, Kaia Bluff and Cartoona Peak at the southeastern end of the plateau, Camp Hill near the southwestern edge of the plateau, Tsekone Ridge at the northwestern end of the plateau near the head of Elwyn Creek canyon and Kana Cone on the extreme northern side of the plateau.[2][21]

Mount Edziza

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Mount Edziza is a nearly symmetrical volcanic cone containing a nearly flat summit with an ice-filled, 2-kilometre (1.2-mile) in diameter crater.[4][22] The symmetry of the volcano is broken by several steep-sided lava domes, including Sphinx Dome, Glacier Dome, Triangle Dome and The Pyramid.[23][24] Surrounding the summit crater is a circular ridge that is breached to the east by active cirques where the remains of several lava lakes are exposed inside the crater.[4] The ridge is partially exposed above the ice cap as a discontinuous series of spires and serrated nunataks; spires forming the southern end of the ridge are the highest. Although the eastern side of Mount Edziza has been deeply dissected by glacial erosion, less dissection has taken place on the southern and northwestern flanks of the volcano.[23] Extending northwest from the northwestern flank of Mount Edziza is Pillow Ridge which is named after its exposures of pillow lava.[25]

About 3 kilometres (1.9 miles) south of the summit is Ice Peak, the southern peak of Mount Edziza.[5][26] This prominent pyramid-shaped horn has an elevation of 2,500 metres (8,200 feet) and is the glacially eroded remains of an older stratovolcano whose northern flank is buried under the younger edifice of Mount Edziza.[4][7] The southern and western flanks of Ice Peak are approximal to those of the original stratovolcano while the eastern flank has been almost completely destroyed by headward erosion of glacial valleys.[8] At its climax, the stratovolcano had a symmetrical profile and contained a small crater at its summit; the current summit is an erosional remnant etched from the eastern crater rim.[4][27]

Desolation Lava Field

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Satellite image of the Big Raven Plateau showing the locations of Mount Edziza, Ice Peak and Cocoa and Coffee craters in the Snowshoe Lava Field

The Desolation Lava Field at the northern end of the Big Raven Plateau consists of blocky basaltic lava flows and wind-sculptured ash beds that erupted from at least 10 cinder cones, most of which are clustered near the northern base of Mount Edziza.[5][28] Lava flows in the Desolation Lava Field range in elevation from more than 1,370 metres (4,490 feet) to 820 metres (2,690 feet) on the shore of Buckley Lake and 670 metres (2,200 feet) inside the Klastline River valley.[29] The largest lava flow is about 14 kilometres (8.7 miles) long and travelled to the northeast into the Kakiddi Creek and Klastline River valleys where it temporarily blocked both streams.[30]

From oldest to youngest, the cinder cones in this lava field are Sleet Cone, Storm Cone, the three Triplex Cones, Sidas Cone, Twin Cone, Moraine Cone, Eve Cone and Williams Cone which range in elevation from 2,135 to 1,430 metres (7,005 to 4,692 feet).[24][31] Eve Cone contains a bowl-shaped crater at its summit and is one of the most symmetrical and best preserved cinder cones in Canada, rising about 150 metres (490 feet) above the central portion of the Desolation Lava Field.[32][33] Williams Cone is the largest, reaching 1.2 kilometres (0.75 miles) wide at its base and rises about 275 metres (902 feet) on the northeastern side of Mount Edziza.[32][34]

Snowshoe Lava Field

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The Snowshoe Lava Field at the southern end of the Big Raven Plateau consists of blocky basaltic lava flows that issued from at least 12 separate vents, most of which are associated with a cinder cone.[5][35] Nearly all of these vents are adjacent to the lower edges of broad glaciers projecting from Mount Edziza's ice cap and occur at elevations greater than 1,800 metres (5,900 feet).[36] Although most of the lava in the Snowshoe Lava Field ponded as thick flows on the gently sloping surface of the Big Raven Plateau, some flowed into the upper canyon of Sezill Creek and into the head of Taweh Creek, as well as into the narrow tributary valleys of Walkout and Shaman creeks.[37]

Tennena Cone, Cocoa Crater, Coffee Crater, Keda Cone and The Saucer are the only named volcanic features in the Snowshoe Lava Field which are 2,350 to 1,920 metres (7,710 to 6,300 feet) in elevation.[5][24] The oldest named feature, Tennena Cone, is a subglacial volcano that formed on the upper western flank of Ice Peak during the Last Glacial Maximum between 23,000 and 18,000 years ago, under an expansion of Mount Edziza's ice cap during the Younger Dryas between 12,900 and 11,600 years ago or during a more recent glacial advance.[38][39][40][41] Cocoa Crater, Coffee Crater and Keda Cone are subaerial cinder cones while The Saucer is a low, nearly circular mound of lava roughly 500 metres (1,600 feet) in diameter.[5][42]

Geology

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Stratigraphy

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The Big Raven Plateau is subdivided into at least 10 geological formations, each being the product of a distinct period of volcanic activity.[5][43] These periods of volcanic activity occurred during five magmatic cycles of the Mount Edziza volcanic complex; each cycle began with the effusion of alkali basalt and culminated with the eruption of lesser volumes of felsic magma.[44] The two oldest geological formations comprising the Big Raven Plateau are the Raspberry and Armadillo formations which were deposted during the first magmatic cycle between 7.5 and 6 million years ago. Overlying these two geological formations are the Nido and Pyramid formations which were deposited by volcanic eruptions between 6 and 1 million years ago during the second magmatic cycle. The fifth, sixth and seventh oldest geological formations comprising the Big Raven Plateau are the Ice Peak, Pillow Ridge and Edziza formations which were deposited during the third magmatic cycle between about 1 and 0.8 million years ago. Volcanic eruptions during the fourth magmatic cycle between 0.8 and 0.2 million years ago deposited the Klastline and Kadiddi formations while the Big Raven Formation, the youngest geological formation comprising the Big Raven Plateau, was deposited by volcanic eruptions during the fifth magmatic cycle in the last 20,000 years.[5][43]

 
Snow-covered Big Raven Plateau

The Raspberry Formation is exposed at the base of prominent escarpments on the western, southwestern and southeastern sides of the Big Raven Plateau.[5] It has an elevation of less than 1,310 metres (4,300 feet) along the Mess Creek Escarpment and consists of flat-lying basaltic lava flows interlayered with scoria.[45]

Armadillo Formation

Nido Formation (Tenchen Member)

Pyramid Formation

Ice Peak Formation

Pillow Ridge Formation

Edziza Formation

Klastline Formation

Kakiddi Formation

Big Raven Formation

Basement

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Stikinia

Provincial park

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Panoramic view of the Big Raven Plateau; Eve Cone is visible as a small dark hill to the right

The Big Raven Plateau lies at the northern end of Mount Edziza Provincial Park, a protected area founded in 1972 to showcase the volcanic landscape.[2][46] This remote wilderness area of northwestern British Columbia is not accessible by motorized vehicles to help protect the very sensitive environment. Instead, access is mainly via aircraft or unmaintained hiking trails that cross creeks.[46] Mount Edziza Provincal Park covers 266,180 hectares (657,700 acres), making it one of the largest provincial parks in British Columbia.[46][47] Hunting, camping, fishing, hiking, wildlife viewing and nature studying are some of the activities available in Mount Edziza Provincial Park.[46]

Wildlife in the area includes moose, caribou, mountain goats, stone sheep, wolves, bears, squirrels, owls, ptarmigans, ravens, gyrfalcons, grouse and migratory songbirds. The climate is characterized by warm summers and cold, snowy winters; temperatures are warmest in mid-summer during the day when they may hit the 30 degrees Celsius (86 degrees Fahrenheit) range. However, temperatures can drop below freezing during summer nights, making snow or freezing rain a possibility at any time of the year.[46]

Accessibility

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The closest roads to the Big Raven Plateau are the Stewart–Cassiar Highway to the southeast and the Telegraph Creek Road to the northwest, both of which extend within 40 kilometres (25 miles) of the plateau.[2][48] Extending from these roads are horse trails that provide access to the Big Raven Plateau.[49] From Telegraph Creek, the Buckley Lake Trail extends about 15 kilometres (9.3 miles) southeast along Mess Creek and Three Mile Lake. It then traverses about 15 kilometres (9.3 miles) northeast along Dagaichess Creek and Stinking Lake to the northeastern end of Buckley Lake where it meets with the Klastline River Trail and the Buckley Lake to Mowdade Lake Route, the latter of which climbs up onto the gently sloping northern side of the Big Raven Plateau.[48]

To the east, the roughly 50-kilometre-long (31-mile) Klastline River Trail begins at the community of Iskut on the Stewart–Cassiar Highway. It extends northwest and west along the Klastline River for much its length. The trail enters Mount Edziza Provincial Park at about 25 kilometres (16 miles) where Kakiddi Creek drains into the Klastline River. After entering Mount Edziza Provincial Park, the Klastline River Trail traverses northwest along the Klastline River for about 10 kilometres (6.2 miles) and then crosses the river north of the Big Raven Plateau. From there, the Klastline River Trail traverses west for about 15 kilometres (9.3 miles) to the northeastern end of Buckley Lake where it meets with the Buckley Lake Trail and Buckley Lake to Mowdade Lake Route junction.[48]

The Big Raven Plateau can also be accessed by float plane or helicopter, both of which are available for charter at the communities of Iskut and Dease Lake.[49] Buckley Lake to the northwest, Nuttlude Lake to the east and Kakiddi Lake, Mowchilla Lake and Mowdade Lake to the southeast are large enough to be used by float-equipped aircraft.[2][46][49] Landing on Buckley Lake and Mowchilla Lake with a private aircraft requires a letter of authorization from the BC Parks Stikine Senior Park Ranger. Private aircraft are prohibited from landing on lava flows that are 1,700 metres (5,500 feet) in elevation or higher.[46]

See also

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References

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  1. ^ a b "Big Raven Plateau". BC Geographical Names. Archived from the original on 2021-09-30. Retrieved 2024-03-14.
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab Telegraph Creek, Cassiar Land District, British Columbia (Topographic map) (3 ed.). 1:250,000. A502 (in English and French). Department of Energy, Mines and Resources. 1989. Archived from the original on 2021-05-02. Retrieved 2021-09-25.
  3. ^ a b c Souther 1992, p. 32.
  4. ^ a b c d e f g Wood, Charles A.; Kienle, Jürgen (1990). Volcanoes of North America: United States and Canada. Cambridge University Press. pp. 124, 125. ISBN 0-521-43811-X.
  5. ^ a b c d e f g h i j k Souther, J. G. (1988). "1623A" (Geologic map). Geology, Mount Edziza Volcanic Complex, British Columbia. 1:50,000. Cartography by M. Sigouin, Geological Survey of Canada. Energy, Mines and Resources Canada. doi:10.4095/133498.
  6. ^ Souther 1992, pp. 32, 224.
  7. ^ a b Souther 1992, pp. 32, 33.
  8. ^ a b c d e f Souther 1992, p. 33.
  9. ^ "Nuttlude Lake". BC Geographical Names. Retrieved 2024-08-03.
  10. ^ "Kakiddi Lake". BC Geographical Names. Retrieved 2024-08-03.
  11. ^ "Elwyn Creek". BC Geographical Names. Archived from the original on 2021-10-01. Retrieved 2023-08-20.
  12. ^ "Taweh Creek". BC Geographical Names. Archived from the original on 2021-10-01. Retrieved 2024-01-23.
  13. ^ "Sezill Creek". BC Geographical Names. Retrieved 2024-01-23.
  14. ^ "Mess Creek". BC Geographical Names. Archived from the original on 2021-08-20. Retrieved 2023-08-23.
  15. ^ "Walkout Creek". BC Geographical Names. Archived from the original on 2020-10-31. Retrieved 2023-04-24.
  16. ^ Souther 1992, p. 241.
  17. ^ "Mount Edziza". BC Geographical Names. Archived from the original on 2018-05-15. Retrieved 2024-08-02.
  18. ^ "Edziza: General Information". Global Volcanism Program. Smithsonian Institution. Archived from the original on 2021-08-10. Retrieved 2021-09-25.
  19. ^ Souther 1992, pp. 26, 213, 214.
  20. ^ Souther 1992, pp. 214, 228, 229.
  21. ^ Souther 1992, pp. 32, 214.
  22. ^ Souther 1992, pp. 175, 177.
  23. ^ a b Souther 1992, p. 175.
  24. ^ a b c "Edziza: Synonyms & Subfeatures". Global Volcanism Program. Smithsonian Institution. Archived from the original on 2021-08-10. Retrieved 2023-08-17.
  25. ^ "Pillow Ridge". BC Geographical Names. Archived from the original on 2021-10-01. Retrieved 2024-05-31.
  26. ^ "Ice Peak". BC Geographical Names. Archived from the original on 2021-09-30. Retrieved 2023-07-05.
  27. ^ Souther 1992, p. 18.
  28. ^ Souther 1992, pp. 213, 214, 216.
  29. ^ Souther 1992, p. 216.
  30. ^ Souther 1992, pp. 217, 222.
  31. ^ Souther 1992, p. 214.
  32. ^ a b Souther 1992, p. 223.
  33. ^ "Stikine volcanic belt: Mount Edziza". Catalogue of Canadian volcanoes. Natural Resources Canada. 2009-04-01. Archived from the original on 2009-06-08. Retrieved 2023-01-29.
  34. ^ "Williams Cone". BC Geographical Names. Archived from the original on 2024-06-09. Retrieved 2024-08-05.
  35. ^ Souther 1992, pp. 27, 230.
  36. ^ Souther 1992, p. 228.
  37. ^ Souther 1992, p. 230.
  38. ^ Souther 1992, pp. 26, 230.
  39. ^ Cunha, Regina L.; Lopes, Evandro P.; Reis, Davide M.; Castilho, Rita (2011). "Genetic structure of Brachidontes puniceus populations in Cape Verde archipelago shows signature of expansion during the last glacial maximum". Journal of Molluscan Studies. 77 (2). Oxford University Press: 175. doi:10.1093/mollus/eyr001. ISSN 0260-1230.
  40. ^ Hungerford, Jefferson D. G.; Edwards, Benjamin R.; Skilling, Ian P.; Cameron, Barry I. (2014). "Evolution of a subglacial basaltic lava flow field: Tennena volcanic center, Mount Edziza volcanic complex, British Columbia, Canada". Journal of Volcanology and Geothermal Research. 272 (2). Elsevier: 39. doi:10.1016/j.jvolgeores.2013.09.012. ISSN 0377-0273.
  41. ^ Fiedel, S. J. (2011). "The mysterious onset of the Younger Dryas". Quaternary International. 242. Elsevier: 262. doi:10.1016/j.quaint.2011.02.044. ISSN 1040-6182.
  42. ^ Souther 1992, p. 233.
  43. ^ a b Souther 1992, p. 267.
  44. ^ Souther 1992, pp. 1, 267, 276.
  45. ^ Souther 1992, p. 47.
  46. ^ a b c d e f g "Mount Edziza Provincial Park". BC Parks. Archived from the original on 2023-01-23. Retrieved 2024-03-28.
  47. ^ "Edziza: Photo Gallery". Global Volcanism Program. Smithsonian Institution. Archived from the original on 2021-09-21. Retrieved 2023-05-03.
  48. ^ a b c Mussio, Russell, ed. (2018). Northern BC Backroad Mapbook. Mussio Ventures. pp. 88, 89, 96. ISBN 978-1-926806-87-7.
  49. ^ a b c Souther 1992, p. 31.

Sources

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