Mount Edziza ( əd-ZY-zə; Tahltan: Tenh Dẕetle [tɛn̥ ˈt͡θɛt͡ɬʰə]) is a volcano in Cassiar Land District of northwestern British Columbia, Canada. It is about 40 kilometres (25 miles) southeast of the community of Telegraph Creek in the middle of the Big Raven Plateau, which is part of the Tahltan Highland. Mount Edziza has an elevation of 2,786 metres (9,140 feet), making it the highest point of the Mount Edziza volcanic complex and one of the highest volcanoes in Canada. However, it had an elevation of at least 3,396 m (11,142 ft) before its formerly cone-shaped summit was likely destroyed by a violent eruption in the geologic past; its current flat summit contains an ice-filled, 2 km (1.2 mi) wide crater. The mountain contains several lava domes, cinder cones and lava fields on its flanks, as well as an ice cap containing several outlet glaciers which extend to lower elevations. All sides of Mount Edziza are drained by tributaries of Mess Creek and Kakiddi Creek, which are situated within the Stikine River watershed. Mount Edziza consists of several types of volcanic rocks and at least six geological formations that formed during six distinct stages of volcanic activity. The first stage, 1.1 million years ago, produced basalt flows and a series of rhyolite and trachyte domes. Basalt flows and smaller amounts of trachyte, tristanite, trachybasalt, benmoreite and mugearite produced during the second stage, about 1 million years ago, compose Ice Peak, a glacially eroded stratovolcano forming the south peak of Mount Edziza. The third and fourth stages, 0.9 million years ago, created basalt ridges and the central trachyte stratovolcano of Mount Edziza, respectively. Thick trachyte flows, most of which have since eroded away, were issued during the fifth stage 0.3 million years ago. The sixth stage began in the last 20,000 years with the eruption of cinder cones, basalt flows and minor trachyte ejecta. Renewed volcanism could block local streams with lava flows, disrupt air traffic with volcanic ash and produce floods or lahars from melting glacial ice. Indigenous peoples have lived adjacent to Mount Edziza for thousands of years. It is a sacred mountain to the Tahltan people, who historically used volcanic glass from it to make tools and weaponry. Mineral exploration just southeast of Mount Edziza had commenced by the 1950s where gold, silver and other metals were discovered. This mineral exploration was conducted by several mining companies into the early 1990s. Mount Edziza and the surrounding area were made into a large provincial park in the early 1970s to preserve the volcanic landscape. The mountain and provincial park can only be accessed by aircraft or by a network of horse trails from surrounding roads.
Name and etymology The mountain was labelled Edziza Peak on Geological Survey of Canada maps as early as 1926. This name for the mountain was adopted by the Geographical Names Board of Canada on September 24, 1945, as identified on the 1926 Geological Survey of Canada map sheet 309A. Edziza Mountain appeared in the 1930 BC Gazetteer, in which the name was erroneously spelled Edzia. On December 3, 1974, the form of name was changed from Edziza Peak to Mount Edziza in accordance with a 1927 British Columbia Land Surveyors report, two world aeronautical charts published in 1950, and three British Columbia maps published in 1931, 1933 and 1943. The form of the name was also changed to reflect entrenched local usage and in conformation with Mount Edziza Provincial Park, which was established in 1972. To the local Tahltan people, Mount Edziza is called Tenh Dẕetle, which translates to 'Ice Mountain'. A number of explanations have been made regarding the origin of the name Edziza. A 1927 report by J. Davidson of the British Columbia Land Surveyors claims that Edziza means 'sand' in the Tahltan language, referring to the deep volcanic ash deposits or pumice-like sand covering large portions of the Big Raven Plateau around Mount Edziza. According to David Stevenson of University of Victoria's Anthropology Department, 'sand' or 'dust' is instead translated as kutlves in Tahltan. An explanation listed in the BC Parks brochure is that Edziza means 'cinders' in the Tahltan language. Another explanation proposed by Canadian volcanologist Jack Souther is that Edziza is a corruption of Edzerza, the name of a local Tahltan family. Obsolete spellings of Edziza include Eddziza, Eddiza, Edidza, Edzia and Etseza.
Geography and geomorphology
Location and climate
Mount Edziza rises from within the middle of the Big Raven Plateau, a barren plateau in Cassiar Land District bounded on the west by Mess Valley, on the north by Klastline Valley, on the east by Kakiddi Valley and on the south by Chakima and Walkout valleys. It lies at the northern end of the Mount Edziza volcanic complex which also includes the smaller Arctic Lake and Kitsu plateaus to the south. This complex of shield volcanoes, stratovolcanoes, lava domes, calderas and cinder cones forms a broad, intermontane plateau at the eastern edge of the Tahltan Highland, a southeast-trending upland area extending along the western side of the Stikine Plateau. Mount Edziza is in the Southern Boreal Plateau Ecosection which consists of several upland summits, wide river valleys and deeply incised plateaus. It is one of seven ecosections composing the Boreal Mountains and Plateaus Ecoregion, a large ecological region of northwestern British Columbia encompassing high plateaus and rugged mountains with intervening lowlands. Boreal forests of black and white spruce occur in the lowlands and valley bottoms of this ecoregion whereas birch, spruce and willow form forests on the mid-slopes. Extensive alpine altai fescue covers the upper slopes, but barren rock is abundant at higher elevations. The region 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. The closest weather stations to Mount Edziza are located at Telegraph Creek and Dease Lake, which lie about 40 km (25 mi) to the northwest and 85 km (53 mi) to the northeast, respectively.
Glaciation
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