|
Volcanism Of Western Canada
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 mound A subglacial mound (SUGM) is a type of subglacial volcano. This type of volcano forms when lava erupts beneath a thick glacier or ice sheet. The magma forming these volcanoes was not hot enough to melt a vertical pipe right through the overlying ...s. Volcanic belts * * * * * * * * * External links Erica A. Massey: A Comparative Study of Glaciovolcanic Palagonitization of Tholeitic and Alkaline Sideromelane in Helgafell, Icland, and Wells Gray-Clearwater Volcanic Filed, BC, Canada. B.Sc., The University of British Columbia, 2014 Volcanic fields * * * See also * * * * ReferencesVolcanoes of Canada . . . . {{Manitoba-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Edziza
Mount Edziza is a stratovolcano in the Stikine Country of northwestern British Columbia, Canada. The volcano and the surrounding area are protected within Mount Edziza Provincial Park. It consists of multiple peaks and ridges, with several glaciers flowing in all directions. The summit is topped by an ice-filled caldera, which is almost wide. The three main peaks around the summit caldera are the southwest summit, the southeast summit and the north summit. Ice Peak overlaps the southern flank of Mount Edziza. Mount Edziza is one of Canada's highest volcanoes at . Snow and ice covered Mount Silverthrone in southwestern British Columbia has a height of . History As early as 10,000 years ago, the Tahltan people, who now live in Dease Lake, Telegraph Creek and the Iskut, used obsidian from Mount Edziza to make tools and weapons for trading material. This is the main source of obsidian found in northwestern British Columbia, which was traded as far away as Alaska and northern Alber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldera
A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is gone. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a Volcanic crater, crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur each century, the formation of a caldera is a rare event, occurring only a few times per century. Only seven caldera-forming collapses are known to have occurred between 1911 and 2016. More recently, a caldera collapse occurred at Kīlauea, Hawaii in 2018. Etymology The term ''caldera'' comes from Spanish language, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Alberta
The geology of Alberta encompasses parts of the Canadian Rockies and thick sedimentary sequences, bearing coal, oil and natural gas, atop complex Precambrian crystalline basement rock. Geologic history, stratigraphy & tectonics The Precambrian granite and gneiss crystalline basement rocks beneath Alberta are extremely ancient, dating to the Archean and Proterozoic. The Slave Craton and Southern Alberta craton are the oldest units at more 2.5 billion years old, while younger units from the Proterozoic include the Wopmay orogeny, Great Slave Lake shear zone, Pre-Taltston basement, Taltson magmatic zone, Athabasca polymetamorphic terrane, Red Earth granulite domain, Kimiwan isotopic anomaly, Ksituan magmatic arc, Virgin River shear zone, Central Alberta intrusions and Lacombe domain. In many cases, Proterozoic deformation overprinted older Archean rocks. The Hudsonian Orogeny from 1.9 to 1.6 billion years ago was the last major regional metamorphic event. Paleozoic (539-251 million ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of British Columbia
The geology of British Columbia is a function of its location on the leading edge of the North American continent. The mountainous physiography and the diversity of rock types and ages hint at the complex geology, which is still undergoing revision despite a century of exploration and mapping. The country's most prominent geological features are mountain ranges, including the North American Cordillera, which stretches from Southern Mexico to Alaska. Terrane theory Terrane theory was first proposed by Jim Monger of the Geological Survey of Canada and Charlie Rouse in 1971 as an explanation for a set of fusulinid fossils found in central British Columbia. Rather than use facies changes or seaways (which were common explanations at the time), the two geologists proposed that the fossils in question had been part of an assemblage of rocks that had migrated across the Pacific Ocean to their present location. This theory was then developed by Porter Irwin and Davy Jones of the US ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanism Of Western Canada
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 mound A subglacial mound (SUGM) is a type of subglacial volcano. This type of volcano forms when lava erupts beneath a thick glacier or ice sheet. The magma forming these volcanoes was not hot enough to melt a vertical pipe right through the overlying ...s. Volcanic belts * * * * * * * * * External links Erica A. Massey: A Comparative Study of Glaciovolcanic Palagonitization of Tholeitic and Alkaline Sideromelane in Helgafell, Icland, and Wells Gray-Clearwater Volcanic Filed, BC, Canada. B.Sc., The University of British Columbia, 2014 Volcanic fields * * * See also * * * * ReferencesVolcanoes of Canada . . . . {{Manitoba-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subglacial Mound
A subglacial mound (SUGM) is a type of subglacial volcano. This type of volcano forms when lava erupts beneath a thick glacier or ice sheet. The magma forming these volcanoes was not hot enough to melt a vertical pipe right through the overlying glacial ice, instead forming hyaloclastite and pillow lava deep beneath the glacial ice field. Once the glaciers had retreated, the subglacial volcano would be revealed, with a unique shape as a result of their confinement within glacial ice. They are somewhat rare worldwide, being confined to regions which were formerly covered by continental ice sheets and also had active volcanism during the same period. They are found throughout Iceland, Antarctica and the Canadian province of British Columbia. Subglacial mounds can be mistaken for cinder cones because they may have a similar shape. An example of this confusion is Pyramid Mountain in the Wells Gray-Clearwater volcanic field The Wells Gray-Clearwater volcanic field, also called the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuya
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. As lava that erupts under a glacier cools very quickly and cannot travel far, it piles up into a steep-sided hill. If the eruption continues long enough, it either melts all the ice or emerges through the top of the ice and then creates normal-looking lava flows that make a flat cap on top of the hill. Discovering and dating the lava flows in a tuya has proven useful in reconstructing past glacial ice extents and thicknesses. Formation Tuyas are a type of subglacial volcano that consists of nearly horizontal beds of lava capping outward-dipping beds of fragmental volcanic rocks, and they often rise in isolation above a surrounding plateau. Tuyas are found in Iceland, British Columbia, the Santiam Pass region in Oregon, the Tyva Republic in eas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maar
A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow crater lake which may also be called a maar. The name comes from a Moselle Franconian dialect word used for the circular lakes of the Daun area of Germany. Notes: * According to German Wikipedia's ''"Maar"'' article, in 1544 in his book ''Cosmographia'', Sebastian Münster (1488–1552) first applied the word "maar" (as ''Marh'') to the Ulmener Maar and the Laacher See. See: Sebastian Münster, ''Cosmographia'' (Basel, Switzerland: Heinrich Petri, 1544)p. 341. From p. 341: ''"Item zwen namhafftiger seen seind in der Eyfel / einer bey de schloß Ulmen / und ein ander bey dem Closter züm Laich / die seind sere tieff / habe kein ynflüß aber vil außflüß / die nennet man Marh unnd seind fischreich."'' (Also two noteworthy lakes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatreme
A diatreme, sometimes known as a maar-diatreme volcano, is a volcanic pipe formed by a gaseous explosion. When magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ... rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater, rapid expansion of heated water vapor and volcanic gases can cause a series of explosions. A relatively shallow crater (known as a ''maar'') is left, and a rock-filled fracture (the actual diatreme) in the crust. Diatremes breach the surface and produce a steep, inverted cone shape. The term ''diatreme'' has been applied more generally to any concave body of broken rock formed by explosive or hydrostatics, hydrostatic forces, whether or not it is related to volcanism. The word comes . Global distribution Maar-diatreme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine Volcano
Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges alone are estimated to account for 75% of the magma output on Earth.Martin R. Speight, Peter A. Henderson, "Marine Ecology: Concepts and Applications", John Wiley & Sons, 2013. . Although most submarine volcanoes are located in the depths of seas and oceans, some also exist in shallow water, and these can discharge material into the atmosphere during an eruption. The total number of submarine volcanoes is estimated to be over 1 million (most are now extinct) of which some 75,000 rise more than 1 km above the seabed. Only 119 submarine volcanoes in Earth's oceans and seas are known to have erupted during the last 11,700 years. Hydrothermal vents, sites of abundant biological activity, are commonly found near submarine volcanoes. Effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenstone Belt
Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean and Proterozoic cratons between granite and gneiss bodies. The name comes from the green hue imparted by the colour of the metamorphic minerals within the mafic rocks: the typical green minerals are chlorite, actinolite, and other green amphiboles. Greenstone belts also often contain ore deposits of gold, silver, copper, zinc and lead. A greenstone belt is typically several dozens to several thousand kilometres long. Typically, a greenstone belt within the greater volume of otherwise homogeneous granite-gneiss within a craton contains a significantly larger degree of heterogeneity and complications and forms a tectonic marker far more distinct than the much more voluminous and homogeneous granites. Additionally, a greenstone belt contains far more information on tectonic and metamorphic events, deformations, and paleogeologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
