|
Hoopers Shoulder
Mount Erebus () is the second-highest volcano in Antarctica (after Mount Sidley), the highest active volcano in Antarctica, and the southernmost active volcano on Earth. It is the List of islands by highest point, sixth-highest ultra mountain on the continent. With a summit elevation of , it is located in the Ross Dependency on Ross Island, which is also home to three inactive volcanoes: Mount Terror (Antarctica), Mount Terror, Mount Bird, and Mount Terra Nova. The volcano has been active since about 1.3 million years ago and has a long-lived lava lake in its inner summit crater that has been present since at least the early 1970s. The volcano was the site of the Air New Zealand Flight 901 accident, which occurred in November 1979. Geology and volcanology Mount Erebus is the world's southernmost active volcano. It is the current eruptive centre of the Erebus hotspot. The summit contains a persistent convecting Phonolite, phonolitic lava lake, one of five long-lasting lav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Peaks By Prominence
This is a list of mountain peaks ordered by their topographic prominence. Terminology The prominence of a peak is the minimum height of climb to the summit on any route from a higher peak, or from sea level if there is no higher peak. The lowest point on that route is the col. For full definitions and explanations of ''topographic prominence'', ''key col'', and ''parent'', see topographic prominence. In particular, the different definitions of the parent of a peak are addressed at length in that article. ''Height'' on the other hand simply means elevation of the summit above sea level. Regarding parents, the ''prominence parent'' of peak A can be found by dividing the island or region in question into territories, by tracing the runoff from the key col (mountain pass) of every peak that is more prominent than peak A. The parent is the peak whose territory peak A resides in. The ''encirclement parent'' is found by tracing the contour below peak A's key col and picking the highe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonolite
Phonolite is an uncommon extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grained) to porphyritic (mixed fine- and coarse-grained). Phonolite is a variation of the igneous rock trachyte that contains nepheline or leucite rather than quartz. Its intrusive equivalent is nepheline syenite. Phonolite is typically fine grained and compact. The name ''phonolite'' comes from the Ancient Greek meaning "sounding stone" due to the metallic sound it produces if an unfractured plate is hit; hence, the English name ''clinkstone'' is given as a synonym. Formation Unusually, phonolite forms from magma with a relatively low silica content, generated by low degrees of partial melting (less than 10%) of highly aluminous rocks of the lower crust such as tonalite, monzonite and metamorphic rocks. Melting of such rocks to a very low degree promotes the liberation of aluminium, potassium, sodium and calcium by melting of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tephritic Phonolite
Tephriphonolite or tephri-phonolite is a mafic to intermediate extrusive igneous rock in composition between phonotephrite and phonolite. It contains 9 to 14% alkali content and 48 to 57% silica content (see TAS diagram). Tephriphonolite is roughly equivalent to tephritic phonolite of the QAPF classification. Tephriphonolite has been found, for example, at Colli Albani volcano in Italy and in the Asunción Rift The Asunción Rift is a composite graben and rift in eastern Paraguay. The rift is at some localities filled with up to 2500 m of sediments. The rift has a width of 40 to 25 km and can be divided in three segments. The western segment has a NW ... of Paraguay. References {{petrology-stub Volcanic rocks Mafic rocks Intermediate rocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porphyritic
Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning all types of igneous rocks can display some degree of porphyritic texture. Most Porphyritic rocks have bimodal size ranges, meaning the rock is composed of two distinct sizes of crystal. In extrusive rocks, the phenocrysts are surrounded by a fine-grained (aphanitic) matrix or groundmass of volcanic glass or non-visible crystals, commonly seen in porphyritic basalt. Porphyritic intrusive rocks have a matrix with individual crystals easily distinguished with the eye, but one group of crystals appearing clearly much bigger than the rest, as in a porphyritic granite. The term comes from the Ancient Greek (), meaning "purple". Purple was the color of royalty, and the "imperial porphyry" was a deep purple igneous rock with large crystals of pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anorthoclase
The mineral anorthoclase ((Na,K)AlSi3O8) is a crystalline solid solution in the alkali feldspar series, in which the sodium-aluminium silicate member exists in larger proportion. It typically consists of between 10 and 36 percent of KAlSi3O8 and between 64 and 90 percent of NaAlSi3O8.Deere, Howie and Zussman, ''Rock Forming Minerals,'' Vol. 4 ''Framework Silicates,'' Wiley, pp. 2 - 5, Fig. 1 Structure and stability Anorthoclase is an intermediate member of the high albite – sanidine alkali feldspar solid solution series. Intermediate members of this series, high albite, anorthoclase and high sodium sanidine are stable at temperatures of and above. Below 400 to 600 °C only very limited solution exists (less than about 5% on both the low albite and microcline ends).Klein, Cornelis and Cornelius S. Hurlbut, Jr. ''Handbook of Mineralogy,'' Wiley, pp. 446-449 (Fig. 11-95 Anorthoclase and high albite exhibit triclinic symmetry, whereas sanidine and the low temperature orthoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratovolcano
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as . Stratovolcanoes are sometimes called composite volcanoes because of their composite stratified structure, built up from sequential outpourings of erupted materials. They are among the most common types of volcanoes, in contrast to the less common shield volca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygenetic Volcanic Field
A polygenetic volcanic field is a group of polygenetic volcanoes, each of which erupts repeatedly, in contrast with monogenetic volcanoes, each of which erupts only once. Polygenetic volcanic fields generally occur where there is a high-level magma chamber. These volcanic fields may show lithological discontinuities due to major changes in magma chemistry, volcanotectonic events, or long erosional intervals, and may last over 10 million years. Unlike monogenetic volcanoes, polygenetic volcanoes reach massive sizes, such as Mauna Loa, which is the world's largest active volcano. Polygenetic volcanoes include stratovolcanoes, complex volcanoes, somma volcanoes, shield volcanoes and 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 ...s. References Volcanology {{Vol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scott Base
Scott Base is a New Zealand Antarctica, Antarctic research station at Pram Point on Ross Island near Mount Erebus in New Zealand's Ross Dependency territorial claim. It was named in honour of Captain Robert Falcon Scott, Royal Navy, RN, leader of two United Kingdom, British expeditions to the Ross Sea area of Antarctica. The base was set up as support to field research and the centre for research into earth sciences, and now conducts research in many fields, operated by Antarctica New Zealand. The base is from the larger U.S. McMurdo Station via Pegasus Road. History Scott Base was originally constructed in support of the UK inspired and privately managed Commonwealth Trans-Antarctic Expedition (TAE). The New Zealand government provided support for the TAE and also for the International Geophysical Year (IGY) project of 1957, five of whose members were attached to the Expedition. In February 1956, 10 months before the TAE and IGY parties were due to head to the Antarctic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McMurdo Station
McMurdo Station is a United States Antarctic research station on the south tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program (USAP), a branch of the National Science Foundation. The station is the largest community in Antarctica, capable of supporting up to 1,258 residents, and serves as one of three year-round United States Antarctic science facilities. All personnel and cargo going to or coming from Amundsen–Scott South Pole Station first pass through McMurdo. By road, McMurdo is 3 kilometres (1.9 mi) from New Zealand's smaller Scott Base. History The station takes its name from its geographic location on McMurdo Sound, named after Lieutenant Archibald McMurdo of . The ''Terror'', commanded by Irish explorer Francis Crozier, along with expedition flagship ''Erebus'' under command of James Clark Ross, first charted the area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromboli
Stromboli ( , ; scn, Struògnuli ) is an island in the Tyrrhenian Sea, off the north coast of Sicily, containing Mount Stromboli, one of the four active volcanoes in Italy. It is one of the eight Aeolian Islands, a volcanic arc north of Sicily. Strabo writes that people believed that this is where Aeolus lived. The island, with an area of , represents the upper third of the volcano. Its population was about 500 . The volcano has erupted many times and is constantly active with minor eruptions, often visible from many points on the island and from the surrounding sea, giving rise to the island's nickname "Lighthouse of the Mediterranean". Etymology Its name is derived from the Ancient Greek name , (Στρογγύλη) which was derived from (, "round"), after the volcano's round, conical appearance when seen from a distance. Height and shape Stromboli is an island in the Tyrrhenian Sea, off the north coast of Sicily, containing Mount Stromboli, one of the three active vol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Geophysical Research
The ''Journal of Geophysical Research'' is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the understanding of the Earth, Sun, and Solar System. It has seven sections: A (Space Physics), B (Solid Earth), C (Oceans), D (Atmospheres), E (Planets), F (Earth Surface), and G (Biogeosciences). All current and back issues are available online for subscribers. History The journal was originally founded under the name ''Terrestrial Magnetism'' by the American Geophysical Union's president Louis Agricola Bauer in 1896. It was renamed to ''Terrestrial Magnetism and Atmospheric Electricity'' in 1899 and in 1948 it acquired its current name. In 1980, three specialized sections were established: ''A: Space Physics'', ''B: Solid Earth'', and ''C: Oceans''. Subsequently, further sections have been added: ''D: Atmospheres'' in 1984, ''E: Planets'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
