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Billy Mitchell (volcano)
Billy Mitchell is a pyroclastic shield in the central part of the island of Bougainville, just north-east of the Bagana Volcano in Papua New Guinea. It is a small pyroclastic shield truncated by a 2 km wide caldera filled by a crater lake. It is named after Billy Mitchell, a 20th-century United States Army general who is regarded as the father of the United States Air Force. The last two major eruptions were in 1580 AD ± 20 years and about 1030 AD. They were among the largest Holocene eruptions in Papua New Guinea. Both were explosive eruptions with a Volcanic Explosivity Index of at least 5. The 1580 AD ± 20 years eruption produced pyroclastic flows and probably formed its caldera. The ignimbrite deposit from that eruption, which had a VEI of 6, extends from the caldera to the coast, and its volume is around . Caldera lake Billy Mitchell caldera lake is about 1,013 m above sea level, has total surface area , and the maximum depth approximately 88.3 m. The only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bagana
Bagana is an active volcanic cone located in the centre of the island of Bougainville, Papua New Guinea, the largest island of the Solomon group. It is the most active volcano in the country, occupying a remote portion of central Bougainville Island. It is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical, roughly 1855-m-high lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is frequent and is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50 m thick with prominent levees that descend the volcano's flanks on all sides. Just north-east of Bagana is the volcan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Crater Lakes
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 sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Shields
Pyroclastic rocks (derived from the el, πῦρ, links=no, meaning fire; and , meaning broken) are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroclasts. Pyroclastic rocks are a type of volcaniclastic deposit, which are deposits made predominantly of volcanic particles. 'Phreatic' pyroclastic deposits are a variety of pyroclastic rock that forms from volcanic steam explosions and they are entirely made of accidental clasts. 'Phreatomagmatic' pyroclastic deposits are formed from explosive interaction of magma with groundwater. Unconsolidated accumulations of pyroclasts are described as tephra. Tephra may become lithified to a pyroclastic rock by cementation or chemical reactions as the result of the passage of hot gases (fumarolic alteration) or groundwater (e.g. hydrothermal alteration and diagenesis) and burial, or, if it is emplaced at temperatures so hot that the soft glassy pyroc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lakes Of Papua New Guinea
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger oceans, they do form part of the Earth's water cycle. Lakes are distinct from lagoons, which are generally coastal parts of the ocean. Lakes are typically larger and deeper than ponds, which also lie on land, though there are no official or scientific definitions. Lakes can be contrasted with rivers or streams, which usually flow in a channel on land. Most lakes are fed and drained by rivers and streams. Natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers, where a river channel has widened into a basin. Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the last ic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanoes Of Bougainville Island
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 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountains Of Papua New Guinea
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher than a hill, typically rising at least 300 metres (1,000 feet) above the surrounding land. A few mountains are isolated summits, but most occur in mountain ranges. Mountains are formed through tectonic forces, erosion, or volcanism, which act on time scales of up to tens of millions of years. Once mountain building ceases, mountains are slowly leveled through the action of weathering, through slumping and other forms of mass wasting, as well as through erosion by rivers and glaciers. High elevations on mountains produce colder climates than at sea level at similar latitude. These colder climates strongly affect the ecosystems of mountains: different elevations have different plants and animals. Because of the less hospitable terrain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Volcanism On Earth
This timeline of volcanism on Earth includes a list of major volcanic eruptions of approximately at least magnitude 6 on the Volcanic explosivity index (VEI) or equivalent sulfur dioxide emission during the Quaternary period (from 2.58 Mya to the present). Other volcanic eruptions are also listed. Some eruptions cooled the global climate—inducing a volcanic winter—depending on the amount of sulfur dioxide emitted and the magnitude of the eruption. Before the present Holocene epoch, the criteria are less strict because of scarce data availability, partly since later eruptions have destroyed the evidence. Only some eruptions before the Neogene period (from 23 Mya to 2.58 Mya) are listed. Known large eruptions after the Paleogene period (from 66 Mya to 23 Mya) are listed, especially those relating to the Yellowstone hotspot, the Santorini caldera, and the Taupō Volcanic Zone. Active volcanoes such as Stromboli, Mount Etna and Kīlauea do not appear on this list, but some back- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Billy Mitchell (Chugach Mountains)
Mount Billy Mitchell is a prominent peak located in the Chugach Mountains, east of Valdez and west of the Copper River in the U.S. state of Alaska. This mountain forms a prominent and easily visible landmark between mile markers 43 and 51 of the Richardson Highway, as the highway passes just to its west between Tonsina and the Thompson Pass (see photograph). Mount Billy Mitchell was named for William "Billy" Mitchell (18791936), a brigadier general of the United States Army Air Service who is often referred to as the "father of the United States Air Force". Naming In response to the Klondike Gold Rush, the United States Army established numerous military outposts throughout the District of Alaska. As a lieutenant in the United States Army Signal Corps, Mitchell was stationed in Alaska at that time. On May 26, 1900, the United States Congress appropriated $450,000 in order to establish a communications system to connect the many isolated and widely separated U.S. Army ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Volcanoes In Papua New Guinea ...
This is a list of active and extinct volcanoes in Papua New Guinea. New Guinea Admiralty Islands Bougainville D'Entrecasteaux Islands New Britain New Ireland Offshore islands References * Volcanoes of the World External links * {{Global Volcanism Program Papua New Guinea * Volcanoes 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anguilla Megastoma
The Polynesian longfinned eel (''Anguilla megastoma''), also known as the Pacific long-finned eel, at www.fishbase.org. is an eel in the family Anguillidae.''Anguilla megastoma'' at www.fishbase.org. It was described by Johann Jakob Kaup in 1856.Kaup, J. J., 1856 ''Catalogue of the apodal fish in the collection of the British Museum.'' London. 1-163, Pls. 1-19. It is a tropical eel found in freshwaters in the Pacific Ocean, Pacific, including Sulawesi, Indonesia; the Society Islands, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
