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Rurutu Hotspot
Arago hotspot (also known as the Rurutu hotspot, Young Rurutu hotspot or Atiu hotspot) is a Hotspot (geology), hotspot in the Pacific Ocean, presently located below the Arago seamount close to the island of Rurutu, French Polynesia. Arago is part of a family of hotspots in the southern Pacific, which include the Society hotspot and the Macdonald hotspot among others. These are structures beneath Earth's crust which generate volcanoes and which are in part formed by mantle plumes, although Arago itself might have a shallower origin. As the Pacific Plate, Pacific plate moves over the hotspots, new volcanoes form and old volcanoes are carried away; sometimes an older volcano is carried over the hotspot and is then uplifted as happened with Rurutu. The Arago hotspot is responsible for the formation of Arago seamount and uplift on Rurutu; however reconstructions of the past positions of tectonic plates and geochemistry suggest that other islands and seamounts were constructed by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilbert Islands
The Gilbert Islands (;Reilly Ridgell. ''Pacific Nations and Territories: The Islands of Micronesia, Melanesia, and Polynesia.'' 3rd. Ed. Honolulu: Bess Press, 1995. p. 95. formerly Kingsmill or King's-Mill IslandsVery often, this name applied only to the southern islands of the archipelago, the northern half being designated as the Scarborough Islands. ''Merriam-Webster's Geographical Dictionary''. Springfield, Massachusetts: Merriam Webster, 1997. p. 594) are a chain of sixteen atolls and coral islands in the Pacific Ocean, about halfway between Papua New Guinea and Hawaii. They constitute the main part of the country of Kiribati (the name of which is a rendering of "Gilberts" in the phonology of the indigenous Gilbertese language, Gilbertese). Geography The atolls and islands of the Gilbert Islands lie in an approximate north-to-south line. The northernmost island in the group, Makin (atoll), Makin, it is approximately from southernmost, Arorae, as the crow flies. Geographi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is commonly defined as a vent or fissure 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 because most of Earth's plate boundaries are underwater, most volcanoes 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 resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions."Mid-ocean ridge tectonics, volcanism and geomorphology." Geology 26, no. 455 (2001): 458. https://macdonald.faculty.geol.ucsb.edu/papers/Macdonald%20Mid-Ocean%20Ridge%20Tectonics.pdf Volcanoes can also form where there is str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macdonald Seamount
Macdonald seamount (named after Gordon A. Macdonald) is a seamount in Polynesia, southeast of the Austral Islands and in the neighbourhood of a system of seamounts that include the Ngatemato seamounts and the Taukina seamounts. It rises from the seafloor to a depth of about and has a flat top, but the height of its top appears to vary with volcanic activity. There are some subsidiary cones such as Macdocald seamount. The seamount was discovered in 1967 and has been periodically active with gas release and seismic activity since then. There is hydrothermal activity on Macdonald, and the vents are populated by hyperthermophilic bacteria. Macdonald seamount is the currently active volcano of the Macdonald hotspot, a volcanic hotspot that has formed this seamount and some other volcanoes. Eruptions occurred in 1967, 1977, 1979–1983 and 1987–1989, and earthquakes were recorded in 2007. The activity, which has produced basaltic rocks, has modified the shape of the volcano and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atoll
An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most of the approximately 440 atolls in the world are in the Pacific Ocean. Two different, well-cited models, the subsidence model and the antecedent karst model, have been used to explain the development of atolls.Droxler, A.W. and Jorry, S.J., 2021. "The Origin of Modern Atolls: Challenging Darwin's Deeply Ingrained Theory". ''Annual Review of Marine Science'', 13, pp. 537–573. According to Charles Darwin's subsidence model, the formation of an atoll is explained by the sinking of a volcanic island around which a coral fringing reef has formed. Over geologic time, the volcanic island becomes extinct and eroded as it subsides completely beneath the surface of the ocean. As the volcanic island subsides, the coral fringing reef becomes a ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantle (geology)
A mantle is a layer inside a planetary body bounded below by a Planetary core, core and above by a Crust (geology), crust. Mantles are made of Rock (geology), rock or Volatile (astrogeology), ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone planetary differentiation, differentiation by density. All Terrestrial planet, terrestrial planets (including Earth), half of the giant planets, specifically ice giants, a number of Asteroid, asteroids, and some planetary Natural satellite, moons have mantles. Examples Earth The Earth's mantle is a layer of Silicate minerals, silicate rock between the Crust (geology), crust and the Earth's outer core, outer core. Its mass of 4.01 × 1024 kg is 67% the mass of the Earth. It has a thickness of making up about 84% of Earth's volume. It is predominantly solid, but in Geologic time scale, geological time it behaves as a Viscosity, visc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitcairn Hotspot
The Pitcairn hotspot is a volcanic hotspot located in the south-central Pacific Ocean. Over the past 11 million years, it has formed the Pitcairn-Gambier hotspot chain. It is responsible for creating the Pitcairn Islands and two large seamounts named Adams and Bounty, as well as atolls at Moruroa, Fangataufa and the Gambier Islands. The hotspot is currently located at Adams and Bounty, which are ~60 kilometers East-Southeast of Pitcairn Island. Current hotspot location The current hotspot location is west of the spreading center known as the East Pacific Rise; an area near where the Nazca plate and the Pacific plate are diverging around 20°S, 115°W. This is where material is thought to be sourced from the core-mantle boundary, rising to surface as a localized plume. Opponents of the hotspot theory instead attribute Pitcairn hotspot to upwelling at the western end of the Easter fracture zone. Morphology Multibeam bathymetry shows that the two largest seamounts, Adams and B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marquesas Hotspot
The Marquesas hotspot is a volcanic hotspot in the southern Pacific Ocean. It is responsible for the creation of the Marquesas Islands – a group of eight main islands and several smaller ones – and a few seamounts. The islands and seamounts formed between 5.5 and 0.4 million years ago and constitute the northernmost volcanic chain in French Polynesia. There are two competing theories concerning the origins of volcanism associated with the Marquesas hotspot. Many geoscientists maintain that the area is underlain by a mantle plume which has transported hot material from the lower mantle to the surface, forming the chain of islands and seamounts as the Pacific Plate moved in a north-westerly direction relative to the stationary plume. Radiometric dating of the youngest volcanic rocks suggests that volcanism is still active. Evidence for a plume origin comes mainly from seismic imaging, with large-scale low velocity anomalies being observed from the core-mantle boundary to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
French Polynesia Relief Map
French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), a British rock band * "French" (episode), a live-action episode of ''The Super Mario Bros. Super Show!'' * ''Française'' (film), a 2008 film * French Stewart (born 1964), American actor Other uses * French (surname), a surname (including a list of people with the name) * French (tunic), a type of military jacket or tunic * French's, an American brand of mustard condiment * French (catheter scale), a unit of measurement * French Defence, a chess opening * French kiss, a type of kiss See also * France (other) * Franch, a surname * French Revolution (other) * French River (other), several rivers and other places * Frenching (other) * Justice French (other) Justice French may refer to: * C. G. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raivavae
Raivavae (Tahitian language, Tahitian: ''Ra‘ivāvae'' International Phonetic Alphabet, /ra.ʔi.va:va.e/) is one of the Austral Islands in French Polynesia. Its total land area including offshore islets is . At the 2022 census, it had a population of 900. The island is of volcanic origin, and rises to elevation at Mont Hiro. History The first sighting by Europeans was recorded by the Spanish naval officer Tomás Gayangos on board of the frigate ''El Aguila'' on 5 February 1775. Gayangos had taken over the command of the expedition of Domingo de Bonechea of 1774 after his death in Tahiti and was returning to the Viceroyalty of Peru. The main source describing this sighting is that of José Andía y Varela, pilot of the packet boat ''Jupiter'' that accompanied ''El Aguila'' in this return trip. On 6 February, a boat was sent in, and made contact with the inhabitants at the shore edge, but landing was not made. Raivavae was charted as ''Santa Rosa'' by the Spaniards, who recorded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polynesians
Polynesians are an ethnolinguistic group comprising closely related ethnic groups native to Polynesia, which encompasses the islands within the Polynesian Triangle in the Pacific Ocean. They trace their early prehistoric origins to Island Southeast Asia and are part of the larger Austronesian ethnolinguistic group, with an Urheimat in Taiwan. They speak the Polynesian languages, a branch of the Oceanic subfamily within the Austronesian language family. The Indigenous Māori people form the largest Polynesian population, followed by Samoans, Native Hawaiians, Tahitians, Tongans, and Cook Islands Māori. , there were an estimated 2 million ethnic Polynesians (both full and part) worldwide. The vast majority either inhabit independent Polynesian nation-states (Samoa, Niue, Cook Islands, Tonga, and Tuvalu) or form minorities in countries such as Australia, Chile (Easter Island), New Zealand, France (French Polynesia and Wallis and Futuna), and the United States (Hawaii and Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
François Arago
Dominique François Jean Arago (), known simply as François Arago (; Catalan: , ; 26 February 17862 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of the Carbonari revolutionaries and politician. Early life and work Arago was born at Estagel, a small village of 3,000 near Perpignan, in the ' of Pyrénées-Orientales, France, where his father held the position of Treasurer of the Mint. His parents were François Bonaventure Arago (1754–1814) and Marie Arago (1755–1845). Arago was the eldest of four brothers. Jean (1788–1836) emigrated to North America and became a general in the Mexican army. Jacques Arago, Jacques Étienne Victor (1799–1855) took part in Louis de Freycinet's exploring voyage in the ''Uranie'' from 1817 to 1821, and on his return to France devoted himself to his journalism and the drama. The fourth brother, Étienne Arago, Étienne Vincent (1802–1892), is said to have collaborated with Honoré de Balzac in ''The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
