A subglacial volcano, also known as a glaciovolcano, is a volcanic form produced by subglacial eruptions or eruptions beneath the surface of a glacier or ice sheet which is then melted into a lake by the rising lava. Today they are most common in Iceland and Antarctica; older formations of this type are found also in British Columbia and Yukon Territory, Canada.
Hyaloclastite is a volcanoclastic accumulation or breccia consisting of glass fragments (clasts) formed by quench fragmentation of lava flow surfaces during submarine or subglacial extrusion. It occurs as thin margins on the lava flow surfaces and between pillow lavas as well as in thicker deposits, more commonly associated with explosive, volatile-rich eruptions as well as steeper topography. Hyaloclastites form during volcanic eruptions under water, under ice or where subaerial flows reach the sea or other bodies of water. It commonly has the appearance of angular flat fragments sized between a millimeter to few centimeters. The fragmentation occurs by the force of the volcanic explosion, or by thermal shock and spallation during rapid cooling.
A tuya is a flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet. They are rare worldwide, being confined to regions which were covered by glaciers and had active volcanism during the same period.
Hoodoo Mountain is a potentially active flat-topped stratovolcano in the Stikine Country of northwestern British Columbia, Canada, located 74 km (46 mi) northeast of Wrangell, Alaska, on the north side of the lower Iskut River and 30 km (19 mi) east of its junction with the Stikine River. It is situated in the Boundary Ranges of the Coast Mountains and existed since the Late Pleistocene stage of the Pleistocene epoch, which began 130,000 years ago and ended 10,000 years ago.
The Tuya volcanic field is a volcanic field of tuyas located in far northern British Columbia, Canada, near the border with the Yukon Territory and focused on the area of the Tuya Range, a subrange of the Stikine Ranges of the Cassiar Mountains, though some vents are in the Kawdy Plateau, the northernmost part of the Stikine Plateau. Several small shield volcanoes, and postglacial lapilli cones and lava flows have been reported in this area. The only nonglacial volcanoes in the field are Gabrielse Cone and the West Tuya lava field.
Tuya Butte is a tuya in the Tuya Range of north-central British Columbia, Canada. It is a bit less isolated from other ranges than neighbouring Mount Josephine. Some of the other volcanoes in the area include South Tuya, Ash Mountain, and Mathews Tuya.
Ash Mountain is the highest summit in the Tuya Range of the Stikine Ranges in northcentral British Columbia, Canada, located immediately north of High Tuya Lake at the north end of Tuya Mountains Provincial Park. It is one of the six tuyas clustered close to Tuya Lake. The base of the volcano comprises pillow lava and hyaloclastite indicating that the volcano formed beneath ice or under a large lake. The volcano comprises loose debris as well as dikes of basaltic rock that intruded into the volcanic pile. Other tuyas in the area include Tuya Butte, South Tuya and Mathews Tuya, although most of the group of tuyas are unnamed.
South Tuya, also called Southern Tuya, is a tuya clustered around Tuya Lake in the Northern Cordilleran Volcanic Province in British Columbia, Canada. The base of South Tuya comprises hyaloclastite and pillow lava indicating that the volcano formed beneath a large lake or beneath ice.
Kawdy Mountain is a subglacial mound on the Kawdy Plateau, the northernmost sub-plateau of the Stikine Plateau in northwestern British Columbia, Canada. It consists of nearly horizontal beds of basaltic lava, capping outward dipping beds of fragmental volcanic rocks and last erupted in Pleistocene. Kawdy Mountain is one of many basaltic volcanic features of the Stikine Volcanic Belt, which is forming because the North American tectonic plate is stretching slightly as it moves to the west.
Several types of volcanic eruptions—during which lava, tephra, and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.
Cinder Mountain is a partly eroded cinder cone at the head of Snippaker Creek, British Columbia, Canada. It is one of the Iskut-Unuk River Cones and is the source of a basaltic lava flow that extends 4 km (2 mi) north into Copper King Creek. An isolated pile of subaerial basalt flows and associated pillow lava rest on varved clay and till in King Creek. Cinder Mountain last erupted during the Pleistocene.
Ne Ch'e Ddhawa is a volcano located 7 km (4.3 mi) upstream from Fort Selkirk in the Fort Selkirk Volcanic Field of central Yukon, Canada. It has been described as a cinder cone or a subglacial mound. The volcano erupted subglacially during the late Pleistocene, erupting hyaloclastite tuffs, breccias, and pillow breccias.
Pillow Ridge is a ridge of the Tahltan Highland in northern British Columbia, Canada, located southeast of Telegraph Creek. It extends northwest from Mount Edziza in Mount Edziza Provincial Park.
The Mount Edziza volcanic complex is a large and potentially active north-south trending complex volcano in Stikine Country, northwestern British Columbia, Canada, located 38 kilometres (24 mi) southeast of the small community of Telegraph Creek. It occupies the southeastern portion of the Tahltan Highland, an upland area of plateau and lower mountain ranges, lying east of the Boundary Ranges and south of the Inklin River, which is the east fork of the Taku River. As a volcanic complex, it consists of many types of volcanoes, including shield volcanoes, calderas, lava domes, stratovolcanoes, and cinder cones.
Volcanism of Western Canada has produced lava flows, lava plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, greenstone belts, submarine volcanoes, calderas, diatremes and maars, along with examples of more less common volcanic forms such as tuyas and subglacial mounds.
Tom MacKay Creek Cone is a basalt subglacial mound in northwestern British Columbia, Canada. It is part of the Iskut-Unuk River Cones group and last erupted during the Pleistocene epoch. There is a single vent and a single flow, of weathered, fragmented pillow basalt, of maximum 30m thickness.
The volcanic history of the Northern Cordilleran Volcanic Province presents a record of volcanic activity in northwestern British Columbia, central Yukon and the U.S. state of easternmost Alaska. The volcanic activity lies in the northern part of the Western Cordillera of the Pacific Northwest region of North America. Extensional cracking of the North American Plate in this part of North America has existed for millions of years. Continuation of this continental rifting has fed scores of volcanoes throughout the Northern Cordilleran Volcanic Province over at least the past 20 million years and occasionally continued into geologically recent times.
The Canadian Cascade Arc, also called the Canadian Cascades, is the Canadian segment of the North American Cascade Volcanic Arc. Located entirely within the Canadian province of British Columbia, it extends from the Cascade Mountains in the south to the Coast Mountains in the north. Specifically, the southern end of the Canadian Cascades begin at the Canada–United States border. However, the specific boundaries of the northern end are not precisely known and the geology in this part of the volcanic arc is poorly understood. It is widely accepted by geologists that the Canadian Cascade Arc extends through the Pacific Ranges of the Coast Mountains. However, others have expressed concern that the volcanic arc possibly extends further north into the Kitimat Ranges, another subdivision of the Coast Mountains, and even as far north as Haida Gwaii.
The Mount Cayley volcanic field (MCVF) is a remote volcanic zone on the South Coast of British Columbia, Canada, stretching 31 km (19 mi) from the Pemberton Icefield to the Squamish River. It forms a segment of the Garibaldi Volcanic Belt, the Canadian portion of the Cascade Volcanic Arc, which extends from Northern California to southwestern British Columbia. Most of the MCVF volcanoes were formed during periods of volcanism under sheets of glacial ice throughout the last glacial period. These subglacial eruptions formed steep, flat-topped volcanoes and subglacial lava domes, most of which have been entirely exposed by deglaciation. However, at least two volcanoes predate the last glacial period and both are highly eroded. The field gets its name from Mount Cayley, a volcanic peak located at the southern end of the Powder Mountain Icefield. This icefield covers much of the central portion of the volcanic field and is one of the several glacial fields in the Pacific Ranges of the Coast Mountains.
The Reykjanes Peninsula in southwest Iceland is the continuation of the mostly submarine Reykjanes Ridge, a part of the Mid-Atlantic Ridge, on land and reaching from Esja in the north and Hengill in the east to Reykjanestá in the west. Suðurnes is an administrative unit covering part of Reykjanes Peninsula.
