Ultramafic rocks are igneous and meta-igneous rocks with a very low silica content, generally >18% MgO, high FeO, low potassium, and are composed of usually greater than 90% mafic minerals. The Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks.
Mathews Tuya is a tuya in northcentral British Columbia. It is one of the six tuyas close to Tuya Lake. It has been partly glaciated and Ar-Ar geochronology shows that is it about 730,000 years old. It mainly comprises palagonitized tephra but also has a few dykes and jointed lava flows on its flanks. The top still has flat-lying lava flows erupted after the tephra pile grew above the surface of the enclosing lake. The other volcanoes in the area include Tuya Butte, South Tuya and Ash Mountain. The volcanoes in the region form part of the Northern Cordilleran Volcanic Province.
Armadillo Peak is a 7.5-million-year-old caldera, located about 3 km north of Bourgeaux Creek and northeast of Raspberry Pass, British Columbia, Canada. It is south of Mount Edziza and is overlapped by the Ice Peak central volcano, which was formed during the early Pleistocene. Its caldera is largely destroyed by glaciers. It is part of the Mount Edziza volcanic complex, which is made of basaltic lava flows.
The Blackfoot diatreme is a diatreme in southeastern British Columbia, Canada, located 60 km (37 mi) northeast of Cranbrook. It is 1,000 m (3,281 ft) in length with a maximum width of 400 m (1,312 ft). The diatreme is elongate in shape, and outcrops east of Blackfoot Creek.
The Cross diatreme is a diatreme in southeastern British Columbia, Canada, located 60 km (37 mi) east of the Rocky Mountain Trench and 8 km (5 mi) northeast of Elkford.
The HP diatreme, also called the HP pipe, is a diatreme in the Rocky Mountains of southeastern British Columbia, Canada, located 50 km (31 mi) northeast of Golden.
The Gahcho Kué kimberlite pipes is a cluster of Cambrian kimberlite diatremes located 280 km (174 mi) northeast of Yellowknife, Northwest Territories, Canada. It consists of four pipes: 5034, Hearne, Tuzo and Tesla.
The Valkyrie pipe is a diatreme in northern Alberta, Canada. It is associated with a group of diatremes called the Birch Mountains kimberlite field which is thought to have formed about 75 million years ago when this part of Alberta was volcanically active during the Late Cretaceous period.
The Jericho pipe is a diamondiferous diatreme in the Slave craton of Nunavut, Canada, located 400 km (249 mi) northeast of Yellowknife near the northern end of Contwoyto Lake. It is home to the now closed Jericho Diamond Mine.
The Legend pipe is a diatreme associated with the Birch Mountains kimberlite field in northern Alberta, Canada. It is thought to have formed about 75 million years ago during the Late Cretaceous period.
The Birch Mountains kimberlite field is a cluster of kimberlitic volcanic pipes or diatremes in north-central Alberta, Canada that were emplaced during a period of kimberlitic volcanism in the Late Cretaceous epoch. As of 2011, 8 diatremes had been discovered in the field, and diamonds and microdiamononds had been recovered during sampling programs.
The Misery Kimberlite Complex is a diatreme cluster in the Northwest Territories, Canada. It was formed approximately 56 million years ago by several overlapping explosive eruptions and intrusions. All seem to have been structurally controlled by zones of weakness related with faults, dikes and a major contact in the Archean basement. The Misery Kimberlite Complex is associated with a field of diamondiferous kimberlites called the Lac de Gras kimberlite field.
The Drybones Bay kimberlite pipe is a diamondiferous diatreme in the Slave craton of the Northwest Territories, Canada. It is the largest diatreme discovered in the Northwest Territories.
The Northern Alberta Kimberlite Province (NAKP) consists of three groups of diatremes or volcanic pipes in north-central Alberta, Canada, most of which are kimberlites and some of which are diamondiferous. They are called the Birch Mountains (BM), Buffalo Head Hills (BHH), and the Mountain Lake cluster (ML), and they were discovered between about 1990 and 1997. Most of the diatremes were emplaced during the Late Cretaceous Epoch although a few are as young as early Paleocene.
K19 pipe is a diatreme in the southwestern part of the Buffalo Head Hills kimberlite field in Northern Alberta, Canada. It is thought to have formed about 60 million years ago, making it one of the youngest volcanic formations in the Buffalo Head Hills kimberlite field and in Alberta. Unlike many other diatremes in the Buffalo Head Hills kimberlite field, it contains low diamond content.
Mount Amorong a potentially active volcano, part of the Amorong Volcanic Group, is located at the northern end of the Luzon Central Plain, in Pangasinan province, Region I, on the island of Luzon, in the Philippines.
Volcanology of Chile studies a continuous volcanic process that has a strong influence on Chilean landscape, geology, economy and society. Volcanism constantly renews the Chilean landscape with lava flows, lava plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes, calderas, diatremes, and maars. However volcanism in Chile as well as in other parts of the world is also associated with several natural hazards such as lahars, earthquakes, pyroclastic flows, toxic gases and ash. Continental Chile has a high concentration of active volcanoes due to its location along the Peru–Chile Trench, a subduction zone where the Nazca and Antarctic Plates are driven beneath the South American Plate. Chile has been subject to volcanism since at least late Paleozoic when subduction along the western margin of South America began. Easter Island, Juan Fernández Islands and other oceanic islands of Chile are extinct volcanoes created by hotspots. Chile has about 500 volcanoes considered active, 60 of which have had recorded eruptions in the last 450 years. The volcanoes with most recorded eruptions are:
Volcanology of Western Canada includes lava flows, lava plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes, calderas, diatremes and maars, along with examples of more less common volcanic forms such as tuyas and subglacial mounds.
