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Williams Cone is a cinder cone on the northeastern flank of Mount Edziza in Cassiar Land District of northwestern British Columbia, Canada. It has an elevation of 2,100 metres (6,900 feet) and is one of several volcanic cones in the Desolation Lava Field at the northern end of the Big Raven Plateau. The cone is southeast of the community of Telegraph Creek in Mount Edziza Provincial Park, which is one of the largest provincial parks in British Columbia. A roughly 13-kilometre-long (8.1-mile) lava flow travelled down the northern side of the Big Raven Plateau from Williams Cone around 630 CE and temporarily dammed the Klastline River. Ejecta from an eruption column was blown eastward by a strong westerly wind, some of which deposited on the eastern flank of Williams Cone.

Williams Cone is part of the Mount Edziza volcanic complex, which consists of diverse landforms such as shield volcanoes, stratovolcanoes, lava domes and cinder cones. A large, steep-sided feature on the western side of Williams Cone resembles an amphitheatre and contains a smaller, nested cinder cone. Tsecha Creek originates adjacent to Williams Cone and is part of the Stikine River watershed. Surrounding Williams Cone are a number of other volcanic features, including Eve Cone, Moraine Cone, Sidas Cone, Sleet Cone, Storm Cone, Twin Cone and the Triplex Cones, which are also part of the Desolation Lava Field.

Name and etymology

The name of the cone became official on January 2, 1980, and was adopted on National Topographic System map 104G/15 after being submitted to the BC Geographical Names office by the Geological Survey of Canada.[2][9] In his 1992 report The Late Cenozoic Mount Edziza Volcanic Complex, British Columbia, Jack Souther gave Williams Cone the numeronym DLF-10; DLF is an acronym for the Desolation Lava Field whereas 10 refers to Williams Cone being the tenth youngest eruptive centre in the Desolation Lava Field.[10]

Williams Cone is named after Hank Williams who was killed in an avalanche near the cone along with Johnny Edzerza in or before 1974.[2][11] The avalanche occurred during a vicious snowstorm that had blown in from the north as Hank Williams, Johnny Edzerza and his wife Eve Edzerza were dog sledding to Iskut from Telegraph Creek 72 km (45 mi) to the west. Eve Edzerza was the only survivor and directed a rescue team to the site of the accident.[12]

Geography

Williams Cone is located in Cassiar Land District of northwestern British Columbia, Canada, about 20 km (12 mi) southeast of Buckley Lake on the northeastern flank of Mount Edziza.[2][4][13] It has an elevation of 2,100 m (6,900 ft) and is one of several volcanic cones in the Desolation Lava Field, which is one of the largest areas of Holocene lava flows in the Mount Edziza volcanic complex.[1][7][14] The 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.[15]

Williams Cone rises more than 275 m (902 ft) above the surrounding terrain and is 1.2 km (0.75 mi) wide at its base, making it the largest cinder cone in the Desolation Lava Field.[6][16] A large, steep-sided feature on the western side of Williams Cone resembles an amphitheatre and contains a smaller cinder cone.[16] Adjacent to Williams Cone is the head of Tsecha Creek, which is covered with loose ejecta from the cone.[4][17] Tsecha Creek is a tributary of Kakiddi Creek; this north-flowing stream enters the Klastline River which flows into the Stikine River.[18][19][20] Williams Cone is therefore within the Stikine River watershed along with the rest of the Mount Edziza volcanic complex.[21]

Apart from Mount Edziza itself which is a 2,786 m (9,140 ft) high stratovolcano, Williams Cone is surrounded by a number of other volcanic features.[1] Extending about 6 km (3.7 mi) to the northwest is a linear group of four volcanic cones; Eve Cone lies at the northwesternmost end of this line whereas the three Triplex Cones are between Eve Cone and Williams Cone.[7] Sleet Cone, Storm Cone and Moraine Cone are about 3 km (1.9 mi) east, southwest and south-southwest of Williams Cone, respectively. About 5 km (3.1 mi) to the northeast is Twin Cone whereas Sidas Cone is about 9 km (5.6 mi) north of Williams Cone.[7][22] About 3 km (1.9 mi) southeast of Williams Cone is The Pyramid on the northeastern flank of Mount Edziza.[7][23] All of these features are part of the Desolation Lava Field at the northern end of the Big Raven Plateau with the exception of The Pyramid, which is separated from its surroundings by a thick apron of active talus.[7][22]

Williams Cone lies in Mount Edziza Provincial Park southeast of the community of Telegraph Creek.[2] With an area of 266,180 hectares (657,700 acres), Mount Edziza Provincial Park is one of the largest provincial parks in British Columbia and was established in 1972 to showcase the volcanic landscape.[24][25] It includes not only the Mount Edziza area, but also the Spectrum Range to the south, which are separated by Raspberry Pass.[4][24] Mount Edziza Provincial Park is in the Tahltan Highland, a southeast-trending upland area extending along the western side of the Stikine Plateau.[4][26]

Geology

Background

As a part of the Mount Edziza volcanic complex, Williams Cone lies within a broad area of volcanoes and lava flows called the Northern Cordilleran Volcanic Province, which extends from northwestern British Columbia northwards through Yukon into easternmost Alaska.[7][27] The dominant rocks comprising these volcanoes are alkali basalts and hawaiites, but nephelinite, basanite and peralkaline 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. The cause of volcanic activity in the Northern Cordilleran Volcanic Province is thought to be due to rifting of the North American Cordillera driven by changes in relative plate motion between the North American and Pacific plates.[28]

Formation

Williams Cone lava flow from the northeast

Williams Cone was formed by a volcanic eruption that involved the accumulation of spatter and bombs around several vents.[16] An eruption column was blown eastward by a strong westerly wind which resulted in the deposition of cinders and ash on the eastern flank of the cone.[5] The ejecta from this eruption column extends 9.5 km (5.9 mi) east across the Big Raven Plateau to the valley of Kakiddi Creek where it is in the form of 1-to-3-millimetre-wide (0.039-to-0.118-inch) particles.[7][29] It increases in both grain size and thickness toward Williams Cone where 5–20 mm (0.20–0.79 in) wide cinders form beds up to 4.5 m (15 ft) thick. Small streams northeast of Williams Cone have exposed former soil underlying ejecta from the volcano.[30]

The formation of Williams Cone was followed by collapse of its western flank near the end of the eruption to form the steep-sided amphitheatre. Some of the debris from this collapse accumulated in mounds west of the amphitheatre, but most of it was rafted away by massive lava from Williams Cone.[31] The lava issued from the breached central crater of Williams Cone, as well as from vents around the base of the cone. Streams of lava from these vents merged to form an approximately 1.5 km (0.93 mi) wide and 13 km (8.1 mi) long compound flow.[30] This lava flow is one of the largest in the Desolation Lava Field and travelled northeast down the northern side of the Big Raven Plateau into the valley of the Klastline River where it formed a temporary lava dam.[5][7]

Williams Cone and its eruptive products are hawaiitic in composition.[7] They are part of the Big Raven Formation and are the most recent additions to the Desolation Lava Field.[7][16] Radiocarbon dating of charred alpine willow twigs preserved in ejecta from Williams Cone indicates that its eruption occurred sometime between 480 and 780 CE, most likely around 630 CE.[8][30] Although Williams Cone is the youngest volcanic cone in the Desolation Lava Field, it may not be the youngest feature of the Mount Edziza volcanic complex; The Ash Pit on the southern side of the Kitsu Plateau may be younger.[7][32]

Basement

Williams Cone from the north

Williams Cone overlies the Edziza, Ice Peak, Nido and Raspberry formations, all of which are older stratigraphic units of the Mount Edziza volcanic complex. The Edziza Formation is the youngest of the four geological formations; it consists mainly of Pleistocene trachyte that is in the form of pyroclastic breccia, lahar or ash flow deposits. Underlying the Edziza Formation is Pleistocene alkali basalt and hawaiite of the Ice Peak Formation, which are in the form of subaerial lava flows or pyroclastic breccia. These volcanic rocks are underlain by alkali basalt lava flows or flow breccias of the Tenchen Member of the Nido Formation; they were erupted from multiple volcanoes during the Pliocene. The oldest geological formation underlying Williams Cone is the Raspberry Formation, which consists of Miocene alkali basalt and minor hawaiite and mugearite. These volcanic rocks are mainly in the form of lava flows, flow breccias and agglutinate.[7][33] Underlying the Raspberry Formation are sedimentary, volcanic and metamorphic rocks of the Stikinia terrane, which are Paleozoic and Mesozoic in age.[7][33][34]

See also

References

Sources

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