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Espenberg Volcanic Field
Espenberg is a volcanic field in Alaska that contains the largest maars on Earth. It was active during the Pleistocene until 17,500 years BP, when a large eruption formed the wide Devil Mountain Maar and deposited tephra over , burying vegetation and forming the largest maar on Earth. Other maars in the field are the North and South Killeak Maars and Whitefish Maar, and Devil Mountain is a shield volcano. The large size of these maars has been attributed to the interaction between permafrost and ascending magma, which favoured intense explosive eruptions. Soils buried underneath the Devil Mountain Maar tephra have been used to reconstruct the regional climate during the last glacial maximum. The maars are part of the Bering Land Bridge National Preserve. Toponyms "Killeak" means "East" in the Inupiaq language. Devil Mountain Maar is also known as "Qitiqliik" or "Kitakhleek" ("Double Lakes") and Whitefish Maar as "Narvaaruaq" or "Navaruk" ("Big Lake"). This volcanic field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devil Mountain (Alaska)
Devil Mountain ( Iñupiaq: ''Iġġiasaaq'') is a small shield volcano in the U.S. state of Alaska, located south of the Devil Mountain Lakes and northwest of Deering. It has an elevation of or . The mountain is part of the Espenberg volcanic field, a group of Pleistocene maars and shield volcanoes at the northern tip of the Seward Peninsula just south of the Arctic Circle. Devil Mountain was named ''Teufelsberg'' by Lieutenant Otto von Kotzebue in 1816, which means ''Devils Mountain'' in the German language German ( ) is a West Germanic languages, West Germanic language mainly spoken in Central Europe. It is the most widely spoken and Official language, official or co-official language in Germany, Austria, Switzerland, Liechtenstein, and the Ita .... References External links * Volcanoes of Alaska Mountains of Alaska Pleistocene shield volcanoes Shield volcanoes of the United States {{NomeAK-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cliff
In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually composed of rock that is resistant to weathering and erosion. The sedimentary rocks that are most likely to form cliffs include sandstone, limestone, chalk, and dolomite. Igneous rocks such as granite and basalt also often form cliffs. An escarpment (or scarp) is a type of cliff formed by the movement of a geologic fault, a landslide, or sometimes by rock slides or falling rocks which change the differential erosion of the rock layers. Most cliffs have some form of scree slope at their base. In arid areas or under high cliffs, they are generally exposed jumbles of fallen rock. In areas of higher moisture, a soil slope may obscure the talus. Many cliffs also fea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand Spit
A spit or sandspit is a deposition bar or beach landform off coasts or lake shores. It develops in places where re-entrance occurs, such as at a cove's headlands, by the process of longshore drift by longshore currents. The drift occurs due to waves meeting the beach at an oblique angle, moving sediment down the beach in a zigzag pattern. This is complemented by longshore currents, which further transport sediment through the water alongside the beach. These currents are caused by the same waves that cause the drift. Hydrology and geology Where the direction of the shore inland ''re-enters'', or changes direction, for example at a headland, the longshore current spreads out or dissipates. No longer able to carry the full load, much of the sediment is dropped. This is called deposition. This submerged bar of sediment allows longshore drift or littoral drift to continue to transport sediment in the direction the waves are breaking, forming an above-water spit. Without the compl ... [...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] |
Devil Mountain Lakes From A Small Plane (4884042722)
A devil is the personification of evil as it is conceived in various cultures and religious traditions. It is seen as the objectification of a hostile and destructive force. Jeffrey Burton Russell states that the different conceptions of the devil can be summed up as 1) a principle of evil independent from God, 2) an aspect of God, 3) a created being turning evil (a ''fallen angel''), and 4) a symbol of human evil. Each tradition, culture, and religion with a devil in its mythos offers a different lens on manifestations of evil.Jeffrey Burton Russell, ''The Devil: Perceptions of Evil from Antiquity to Primitive Christianity'', Cornell University Press 1987 , pp. 41–75 The history of these perspectives intertwines with theology, mythology, psychiatry, art, and literature developing independently within each of the traditions. It occurs historically in many contexts and cultures, and is given many different names—Satan, Lucifer, Beelzebub, Mephistopheles, Iblis—and attri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial planet, rocky planet or natural satellite, moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of volcanism on Venus, Venus, which cover ~80% of the surface, are basaltic; the lunar mare, lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Back-arc
A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of them result from tensional forces, caused by a process known as oceanic trench rollback, where a subduction zone moves towards the subducting plate. Back-arc basins were initially an unexpected phenomenon in plate tectonics, as convergent boundaries were expected to universally be zones of compression. However, in 1970, Dan Karig published a model of back-arc basins consistent with plate tectonics. Structural characteristics Back-arc basins are typically very long and relatively narrow, often thousands of kilometers long while only being a few hundred kilometers wide at most. For back-arc extension to form, a subduction zone is required, but not all subduction zones have a back-arc extension feature. Back-arc basins are found in area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Flow
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is also often called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. The word ''lava'' comes from Italian and is probably derived from the Latin word ''labes'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cinder Cone
A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around the vent to form a cone that often is symmetrical; with slopes between 30 and 40°; and a nearly circular ground plan. Most cinder cones have a bowl-shaped crater at the summit. Mechanics of eruption Cinder cones range in size from tens to hundreds of meters tall and often have a bowl-shaped crater at the summit. They are composed of loose pyroclastic material (cinder or scoria), which distinguishes them from ''spatter cones'', which are composed of agglomerated volcanic bombs. The pyroclastic material making up a cinder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goodhope Bay
Goodhope Bay is a small bay in the Kotzebue Sound, on the Chukchi Sea-facing coast of Alaska. It is across. It is located on the northern coast of the Seward Peninsula, 30 mi. W of Deering; Kotzebue-Kobuk Low . Lieutenant Otto von Kotzebue Otto von Kotzebue (russian: О́тто Евста́фьевич Коцебу́, tr. ; – ) was a Russian officer and navigator in the Imperial Russian Navy. He was born in Reval. He was known for his explorations of Oceania. Early life ... named the area while exploring the region in August 1816, as he had had "good hope" in making important geographic discoveries. References * Bays of Alaska Bodies of water of Northwest Arctic Borough, Alaska Bays of the Chukchi Sea {{NorthwestArcticAK-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chukchi Sea
Chukchi Sea ( rus, Чуко́тское мо́ре, r=Chukotskoye more, p=tɕʊˈkotskəjə ˈmorʲɪ), sometimes referred to as the Chuuk Sea, Chukotsk Sea or the Sea of Chukotsk, is a marginal sea of the Arctic Ocean. It is bounded on the west by the Long Strait, off Wrangel Island, and in the east by Point Barrow, Alaska, beyond which lies the Beaufort Sea. The Bering Strait forms its southernmost limit and connects it to the Bering Sea and the Pacific Ocean. The principal port on the Chukchi Sea is Uelen in Russia. The International Date Line crosses the Chukchi Sea from northwest to southeast. It is displaced eastwards to avoid Wrangel Island as well as the Chukotka Autonomous Okrug on the Russian mainland. Geography The sea has an approximate area of and is only navigable about four months of the year. The main geological feature of the Chukchi Sea bottom is the Hope Basin, which is bound to the northeast by the Herald Arch. Depths less than occupy 56% of the total ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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