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46-524: Arctic Lake Plateau 57°17′59″N 130°46′06″W  /  57.29972°N 130.76833°W  / 57.29972; -130.76833 The Big Raven Formation is a stratigraphic unit of Quaternary age in northwestern British Columbia , Canada. It is the youngest and least voluminous geological formation of the Mount Edziza volcanic complex (MEVC); it overlies at least six older formations of this volcanic complex. The main volcanic rocks of

92-642: A drainage system. Extending 700 metres (2,300 feet) north and 500 metres (1,600 feet) west of Nahta Cone are two tephra deposits, suggesting it was active twice during different wind directions. Northeast of Nahta Cone on the south flank of Kuno Peak in the Spectrum Range are the remains of a Big Raven pyroclastic cone. The remains consist of steeply dipping beds of coarse agglutinated pyroclastic rocks and basaltic lava flows that overlie thick felsenmeer and talus deposits. Much of this cone has been destroyed by repeated landslides and solifluction on Kuno Peak,

138-531: A long and narrow graben -like depression bounded by steeply- dipping faults that extend to the north. A more than 24 km-long (15 mi) fault along the eastern edge of this structure shows signs of having been active contemporaneously with volcanism of the Mount Edziza volcanic complex . It has vertically displaced Holocene basalt flows by 15 to 20 m (50 to 70 ft) and older basalt flows by 91 to 122 m (299 to 400 ft), such that

184-620: A much smaller Big Raven lava field near the edge of an escarpment ; at least three separate vents are in this lava field. Two isolated Big Raven vents on and adjacent to the Arctic Lake Plateau produced lava flows, as did two isolated Big Raven vents in Walkout Creek valley. Most Big Raven vents are marked by a cone of pyroclastic rocks . Stratigraphically , the Big Raven Formation is the youngest unit of

230-476: A narrow, wedge-shaped notch on the eastern flank of Mount Edziza. The northernmost Big Raven vent and the northernmost vent of the entire MEVC is marked by the nested Kana Cone which rises about 60 metres (200 feet) above the surrounding terrain . Its summit contains a roughly 20-metre-deep (66-foot) crater that is breached to the north, exposing oxidated bombs and spatter. Lava from the crater breach extends downslope into Klastline Valley where it temporarily dammed

276-416: A recently active eruptive centre of the Mount Edziza volcanic complex. The Mess Creek Hot Springs 7 km (4.3 mi) south of Mess Lake have a recorded temperature of 42.5 °C (108.5 °F) and may be discharging from a deeply circulating hydraulic system along a major fault on the western side of Mess Creek valley. The historic Yukon Telegraph Trail runs along the eastern side of Mess Creek. It

322-496: Is characterized by hummocky , ridge and trough topography. As a result, some of this lava was forced to flow into depressions paralleling minor landslide scarps. The heavily eroded eastern flank of Mount Edziza contains at least three satellitic centres of the Big Raven Formation. Cinder Cliff consists of thin, slaggy basalt flows that ponded against an ice dam in the upper part of Tenchen Valley . Tuff breccia and ash, as well as glacial and fluvial gravel, form mixed deposits at

368-492: Is classified as 38.7% conifer forest , 25% barren , 15.9% shrubland , 10% snow/glacier, 8.3% herbaceous and small amounts of other cover. Mess Creek originates from an unnamed lake behind an alluvial fan at 57°07′42″N 130°56′12″W  /  57.12833°N 130.93667°W  / 57.12833; -130.93667 . From its source the creek flows about 45 km (28 mi) north into Mess Lake and then continues northwest for another 63 km (39 mi) into

414-472: Is mostly covered over by air-fall pumice of the Sheep Track Member. As a result, the surface details of most of the upper lava flows in this lava field remain obscured and the cones are mantled with Sheep Track pumice. The Snowshoe Lava Field contains three subglacial cones , Tennena Cone being the only one named. Tennena Cone consists of a pile of tuff breccia and pillow basalt and is one of

460-538: Is named. Two unnamed transitional cones are on the southwestern edge of Mount Edziza's summit ice cap inside the alpine trim lines, both of which have been reduced to low, drumlin -like ridges as a result of glacial ice overridding them. The three other transitional cones are unglaciated, having formed at lower elevations just below the terminal alpine moraine. Their inner structures have been exposed by sufficient erosion but they still retain their central craters and original conical form. One of these cones, Coffee Crater ,

506-402: Is the second named right tributary which flows northwest and then north into Mess Creek. The third named right tributary is Raspberry Creek which flows northwest into Mess Creek. Taweh Creek , the fourth named right tributary, flows northwest into Mess Creek west of Mount Edziza . The fifth named right tributary, Crayke Creek , flows southwest into Mess Creek off Mount Edziza. Elwyn Creek

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552-467: Is the sixth named right tributary which flows west into Mess Creek. The seventh named right tributary is Dagaichess Creek which flows southeast into Mess Creek just south of Telegraph Creek. Only two left tributaries of Mess Creek are named. The first one is Schaft Creek which flows north into Mess Creek on the west side of Mount Edziza Provincial Park. The other named left tributary, Tudadela Creek, flows north into Mess Creek. Mess Creek flows through

598-677: Is the youngest vent of the Mess Lake Lava Field; it may also be the youngest vent of the entire MEVC. The Ash Pit was the source of a 2.5-kilometre-wide (1.6-mile) and 6.5-kilometre-long (4.0-mile) tephra deposit on the Kitsu Plateau that extends to the northeast. It was also the source of a lava flow that travelled down Nagha Creek valley towards the eastern side of Mess Lake, portions of which are buried under stream gravel, outwash and braided channel deposits. Arctic Lake Plateau The Arctic Lake Plateau , also called

644-614: Is widespread throughout the MEVC, occurring on or adjacent to the Arctic Lake , Big Raven and Kitsu plateaus. Two lava fields of the Big Raven Formation occur on the Big Raven Plateau which in total contain at least 22 separate vents that issued lava flows. At least four isolated Big Raven vents occur on the eastern flank of Mount Edziza and on the extreme northern slope of the Big Raven Plateau. The Kitsu Plateau contains

690-602: The Arctic Plateau , is a plateau in northwestern British Columbia , Canada . It is located northeast of Arctic Lake at the south end of Mount Edziza Provincial Park . This Arctic Lake should not be confused with the other Arctic Lakes in British Columbia, which lie northeast of the city of Prince George in a pairing known as the Arctic and Pacific Lakes , which with their adjoining mountain ranges are at

736-617: The Klastline River . The two youngest cinder cones in the Desolation Lava Field, Eve Cone and Williams Cone , produced basaltic lava that flowed to Buckley Lake and the Klastline River, respectively. A radiocarbon date of 610 CE ± 150 years has been obtained from willow twigs preserved in ejecta from Williams Cone. Some of the lava flows comprising the Desolation Lava Field issued from vents adjacent to

782-410: The Walkout Creek centres occur on the northern and western sides of Walkout Creek valley, both of which are largely buried and deeply eroded. The larger cone on the northern side of the valley is of geological interest because it was constructed on top of an active, slow moving landslide . Although both cones produced lava flows, lava from the larger cone was controlled by the underlying landslide which

828-591: The Big Raven Formation are alkali basalts and hawaiites , although a small volume of trachyte comprises the Sheep Track Member . These rocks were deposited by volcanic eruptions in the last 20,000 years during the latest magmatic cycle of the MEVC. Alkali basalt and hawaiite are in the form of lava flows and small volcanic cones while trachyte of the Sheep Track Member is mainly in the form of volcanic ejecta which covers an area of about 40 square kilometres (15 square miles). The Big Raven Formation

874-625: The Big Raven Formation overlies the Nido Formation east of Mount Edziza. Big Raven breccia on the plateau surface east of Mess Lake directly overlies trachyte of the Armadillo Formation. The exact age of the Big Raven Formation is unknown but its oldest rocks were probably deposited during the Last Glacial Maximum at least 20,000 years ago which corresponds with the beginning of the latest magmatic cycle of

920-476: The Big Raven Formation, as well as on the eastern flank of Mount Edziza and along Walkout Creek. Trachyte represents a small volume of the Big Raven Formation and mainly comprises air-fall pumice of the Sheep Track Member. The Big Raven Formation is widespread throughout the MEVC, occurring on or adjacent to the Kitsu, Arctic Lake and Big Raven plateaus. The Big Raven Plateau is the main physiographic feature at

966-454: The Klastline River, both of which have since etched new channels around or through the lava flow. The presence of lacustrine silt in small terraces upstream from the lava flow suggests that both streams were dammed long enough to form temporary lakes. The Snowshoe Lava Field is a group of volcanic cones and blocky basalt flows similar in age to the Desolation Lava Field. It covers an area of about 40 square kilometres (15 square miles) and

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1012-574: The Klastline River; the river has since etched a new channel along the northern valley wall. The lava continued to flow downstream through Klastline Valley and possibly reached the Stikine River where Big Raven lava flows overlie about 100 metres (330 feet) of sediment at the mouths of the Klastline and Tahltan rivers. Two isolated occurrences of the Big Raven Formation occur on the Arctic Lake Plateau, Nahta Cone near its northern edge being

1058-583: The MEVC. A Holocene age for its younger rocks has not been wholly determined from geologic dating but rather from the lack of evidence suggesting that they were overridden by the Cordilleran Ice Sheet which retreated from the area about 11,000 years ago. Tephrochronological , radiocarbon and fission track dating has yielded ages of 6520 BCE ± 200 years, 750 BCE ± 100 years, 610 CE ± 150 years and 950 CE ± 6000 years for some Big Raven volcanic rocks at Mount Edziza. Alkali basalt and hawaiite are

1104-620: The MEVC. It is separated from the Klastline Formation by a layer of moraine that was deposited by retreating glaciers at the end of the last glacial period . The Big Raven Formation overlies the Ice Peak Formation north and south of Mount Edziza. An outlier of the Big Raven Formation is separated from the Spectrum Formation by a thick layer of unconsolidated felsenmeer and talus . Another outlier of

1150-605: The Sheep Track Formation had been reassigned as a member of the Big Raven Formation; its recognition as a geological formation has since been abandoned. The Big Raven Formation is the least voluminous geological formation of the MEVC, consisting of 1.7 cubic kilometres (0.41 cubic miles) of volcanic material. The Big Raven Formation overlies the Klastline , Edziza , Ice Peak, Spectrum, Nido , Armadillo and Raspberry formations, all of which are older units of

1196-564: The Snowshoe Lava Field flows and cinder cones, The Saucer is covered by only thin drifts of wind-blown pumice and may postdate the Sheep Track eruption. The source of the Sheep Track pumice remains unknown but it probably originated from a vent hidden under Tencho Glacier. Fission track dating of Sheep Track pumice on the southwestern flank of Ice Peak has yielded an age of 950 CE ± 6000 years. Two small Big Raven cones called

1242-593: The Spectrum Range to the east and Mess Creek valley to the west. The Big Raven Plateau contains the Desolation Lava Field on the northern flank of Mount Edziza which consists of several lava flows that issued from at least 10 separate Big Raven vents. Another area of Big Raven lava flows called the Snowshoe Lava Field occurs on the western flank of Ice Peak; it issued from at least 12 separate vents. The Sheep Track Member overlies much of

1288-601: The Stikine River. About midway through its course, Mess Creek is bounded on the east by the Mess Creek Escarpment . This is a long, often cliff-like feature forming the western edge of the Mount Edziza volcanic complex . The final 12 km (7.5 mi) of Mess Creek flows through a gorge. Mess Creek contains seven named right tributaries . The first one is Tadekho Creek which flows northwest into Mess Creek just south of Mess Lake. Kitsu Creek

1334-589: The base of Clinder Cliff. Icefall Cone on the northeastern spur of Tennaya Cirque and Ridge Cone on the western rim of Idiji Cirque are remnants of two Big Raven eruptive centres that have been greatly modified by mass wasting and alpine glaciation. They both consist of agglutinated spatter, bombs , cinders and slaggy basalt flows; the lava flows are almost completely buried under talus, moraine, fluvial gravel and glacial ice. An intermittently exposed basalt flow extending to near Kakiddi Lake may have issued from Icefall Cone, Ridge Cone or an undiscovered vent inside

1380-481: The edge of the Mess Creek Escarpment where they most likely cascaded into Mess Creek valley, but no evidence of this phenomenon has been found on or below the escarpment. At the southern end of the Mess Lake Lava Field on the steep, south-facing side of Nagha Creek is the third separate vent called The Ash Pit . This 60-metre-deep (200-foot) and 0.4-kilometre-in diameter (0.25-mile) conical depression

1426-598: The former of which also buried lava flows on the Arctic Lake Plateau that originated from this cone. The Mess Lake Lava Field is an area of lava flows and tephra deposits between Raspberry Creek in the north, Nagha Creek in the south and Mess Lake in the east. It covers an area of about 18 square kilometres (6.9 square miles) and contains three separate vents of Big Raven age. The two oldest vents are marked by slightly eroded pyroclastic cones whose craters and cone-shaped structures are still apparent despite being somewhat rounded. Lava flows from both cones travelled westward to

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1472-490: The late Cenozoic Mount Edziza volcanic complex in northwestern British Columbia, Canada. It contains one sub-unit called the Sheep Track Member which is lithologically distinct from the rest of the Big Raven Formation. Initially, the Big Raven Formation and the Sheep Track Member were recognized as two separate geological formations by Jack Souther , Richard Lee Armstrong and J. Harakal in 1984; both formations were grouped together in their descriptions and mapping. By 1988,

1518-422: The main volcanic rocks comprising the Big Raven Formation, having erupted from at least 30 vents along the entire north–south trending axis of the MEVC. They are in the form of lava flows and pyroclastic cones which largely comprise two lava fields on the northern and western flanks of Mount Edziza and Ice Peak , respectively. Isolated pyroclastic cones and lava flows occur at the northern and southern extremities of

1564-399: The more than 150-square-kilometre (58-square-mile) Desolation Lava Field. This is the largest lava field of the Big Raven Formation, as well as one of the youngest volcanic features on Mount Edziza. Sleet Cone and Storm Cone , the oldest cones in the Desolation Lava Field, were sources of lava flows that directly travelled over glacial till . The Triplex Cones issued lava that flowed to near

1610-413: The northeast issued the most voluminous lava in the Snowshoe Lava Field, having flowed westward where it engulfed an area more than 3 kilometres (1.9 miles) wide and 8 kilometres (5.0 miles) long. This lava then continued to flow westward into upper Taweh Valley where it transformed into a relatively narrow flow that formerly extended to near Mess Creek. A subaerial vent referred to as The Saucer produced

1656-492: The northern trim line of Mount Edziza's summit ice cap where meltwater interacted with the erupting lava to form tuff rings . These tuff rings composed of quenched breccia later transitioned into normal subaerial cinder cones as the progressing eruptions displaced ice and meltwater. The more than 12-kilometre-long (7.5-mile) lava flow from Williams Cone formed a temporary dam across the Klastline River at its distal end. Lava from Moraine Cone temporarily dammed Kakiddi Creek and

1702-462: The northern end of the MEVC; its dominant feature is Mount Edziza which rises from the middle of the plateau. Further south near the middle of the MEVC is the Kitsu Plateau which is bounded on the north by Raspberry Pass , on the west by the Mess Creek Escarpment and on the south by the Spectrum Range . The Arctic Lake Plateau is a nearly flat upland at the southern end of the MEVC between

1748-830: The northwestern extremity of the McGregor Plateau . This article about a location in the Interior of British Columbia , Canada is a stub . You can help Misplaced Pages by expanding it . Mess Lake Mess Creek's watershed covers 2,330 km (900 sq mi) and its estimated mean annual discharge is 59.3 m /s (2,090 cu ft/s). The mouth of Mess Creek is located about 3 km (1.9 mi) southwest of Telegraph Creek , about 73 km (45 mi) west of Iskut and about 94 km (58 mi) southwest of Dease Lake in Cassiar Land District . Mess Creek's watershed's land cover

1794-531: The oldest cones in the Snowshoe Lava Field. A smaller unnamed subglacial cone 1.5 kilometres (0.93 miles) to the south also consists of a pile of pillow basalt and tuff breccia. Further south at the southern terminus of Tencho Glacier is another unnamed pile of tuff breccia and pillow basalt. It may be the remains of a tuff ring that has been glacially modified after having formed in a meltwater lake when Tencho Glacier existed at lower elevations. The Snowshoe Lava Field contains five transitional cones, one of which

1840-467: The south shore of Buckley Lake more than 12 kilometres (7.5 miles) to the northwest. Sidas Cone and Twin Cone are complex volcanic piles resulting from simultaneous, multi-vent lava fountaining . Both cones issued relatively thin clinkery-surfaced basalt flows that are sparsely porphyritic . Moraine Cone was the source of a lava flow that travelled northeast into Kakiddi Valley near its junction with

1886-552: The southern end of the Big Raven Plateau, including the Snowshoe Lava Field. At least three Big Raven vents occur on the eastern flank of Mount Edziza and comprise another volcanic zone called the east slope centres. An isolated Big Raven vent called Kana Cone occurs on the extreme northern slope of the plateau while two cinder cones occur on the southern slope of the plateau in Walkout Creek valley. Blocky basalt flows, wind-sculptured ash beds and cinder cones comprise

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1932-412: The southernmost vent of Big Raven age. This cone overlies a glacially-scoured limestone hill and contains a crater that is breached to the east. At least five small conelets comprise Nahta Cone, the largest of which has a topographic relief of approximately 60 metres (200 feet). The breach in the eastern crater rim served as a passageway for at least two highly fluid lava flows that travelled north along

1978-413: The western margin of Tencho Glacier while the smallest fragments form a circular area at least 10 kilometres (6.2 miles) in diameter. Erosion has largely removed the Sheep Track pumice from drainage channels of small intermittent streams on the upper Big Raven Plateau but deposits as much as 2 metres (6.6 feet) thick occur in interfluvial areas. Although the Sheep Track pumice was deposited on nearly all of

2024-625: The western side of the fault has been downthrown. The downthrowing of this fault during the Holocene may have been due to the draining of magma chambers following eruptions at the Mount Edziza volcanic complex. Two groups of hot springs occur along Mess Creek. The Mess Lake Hot Springs near the southeastern corner of Mess Lake have deposited massive tufa over an area of more than 120 ha (300 acres). Discharge at these hot springs may be linked to shallow hydrothermal systems driven by residual magmatic heat as they are adjacent to The Ash Pit ,

2070-622: The youngest lava flow in the Snowshoe Lava Field from near the southern edge of Mount Edziza's summit ice cap. Unlike the other three subaerial centres, The Saucer flow appears to have issued without any accompanying lava fountaining, resulting in no cinder cone development. The southwestern flank of Ice Peak and the surrounding Big Raven Plateau are blanketed with loose, air-fall tephra of the Sheep Track Member. It covers an area of about 40 square kilometres (15 square miles) and consists of pumice fragments that range in size from snowball-sized chunks to pea-sized debris. The largest fragments occur along

2116-443: Was the source of a lava flow that extended to the southwest; the northern edge of the terminal lobe of this lava flow forms a prominent, 18-metre-high (59-foot) escarpment. Three subaerial cones exist in the Snowshoe Lava Field, two of which are named. The largest subaerial cone, Cocoa Crater , produced a 2-kilometre-wide (1.2-mile) lava flow that travelled into upper Sezill Creek canyon. Keda Cone and an unnamed subaerial cone to

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