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Mid-Pacific Mountains
The Mid-Pacific Mountains (MPM) is a large oceanic plateau located in the central North Pacific Ocean or south of the Hawaiian–Emperor seamount chain. Of volcanic origin and Mesozoic in age, it is located on the oldest part of the Pacific Plate and rises up to ( Darwin Rise) above the surrounding ocean floor and is covered with several layers of thick sedimentary sequences that differ from those of other plateaux in the North Pacific. About 50 seamounts are distributed over the MPM. Some of the highest points in the range are above sea level which include Wake Island and Marcus Island. The ocean floor of the MPM dates back to the Jurassic-Cretaceous, some of the oldest oceanic crust on Earth. The MPM is a range of guyots with a lava composition similar to those found in Iceland and the Galapagos Islands, and they probably formed similarly at or near a rift system. In the Cretaceous, they formed large tropical islands located closer to the Equator that began to sink in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic Plateau
An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides. There are 184 oceanic plateaus in the world, covering an area of or about 5.11% of the oceans. The South Pacific region around Australia and New Zealand contains the greatest number of oceanic plateaus (see map). Oceanic plateaus produced by large igneous provinces are often associated with hotspots, mantle plumes, and volcanic islands — such as Iceland, Hawaii, Cape Verde, and Kerguelen. The three largest plateaus, the Caribbean, Ontong Java, and Mid-Pacific Mountains, are located on thermal swells. Other oceanic plateaus, however, are made of rifted continental crust, for example the Falkland Plateau, Lord Howe Rise, and parts of Kerguelen, Seychelles, and Arctic ridges. Plateaus formed by large igneous provinces were formed by the equivalent of continental flood basalts such as the Deccan Traps in India and the Snak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resolution Guyot
Resolution Guyot (formerly known as Huevo) is a guyot (tablemount) in the underwater Mid-Pacific Mountains in the Pacific Ocean. It is a circular flat mountain, rising above the seafloor to a depth of about , with a wide summit platform. The Mid-Pacific Mountains lie west of Hawaii and northeast of the Marshall Islands, but at the time of its formation the guyot was located in the Southern Hemisphere. The guyot was probably formed by a hotspot (geology), hotspot in today's French Polynesia before plate tectonics shifted it to its present-day location. The Easter hotspot, Easter, Marquesas hotspot, Marquesas, Pitcairn hotspot, Pitcairn and Society hotspot, Society hotspots, among others, may have been involved in the formation of Resolution Guyot. Volcanic activity has been radiometric dating, dated to have occurred 107–129 million years ago and formed a volcanic island that was subsequently flattened by erosion. Carbonate deposition commenced, forming an atoll-like structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plateaus Of The Pacific Ocean
In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides have deep hills or escarpments. Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Plateaus are classified according to their surrounding environment as intermontane, piedmont, or continental. A few plateaus may have a small flat top while others have wide ones. Formation Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, Plate tectonics movements and erosion by water and glaciers. Volcanic Volcanic plateaus are produced by volcanic activity. The Columbia Plateau in the north-western United States is an example. They may be formed by upwelling of volcanic magma or extrusion of lava. The un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Easter Microplate
Easter Plate is a tectonic List of tectonic plates#Microplates, microplate located to the west of Easter Island off the west coast of South America in the middle of the Pacific Ocean, bordering the Nazca Plate to the east and the Pacific Plate to the west. It was discovered from looking at earthquake distributions that were offset from the previously perceived Nazca-Pacific Divergent boundary. This young plate is 5.25 million years old and is considered a microplate because it is small with an area of approximately . Seafloor spreading along the Easter microplate's borders have some of the highest global rates, ranging from /yr. Structure and tectonics (present) From the 1970s to 1990s, multiple efforts were made to collect data on the area, including several Magnetic anomaly, magnetic and gravitational anomaly surveys. These surveys show that Easter plate is uniquely shallow, bordered by spreading centers and Transform Boundaries, transform boundaries, with a triple junction loc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific-Farallon Ridge
The Pacific-Farallon Ridge was a spreading ridge during the Late Cretaceous that extended 10,000 km in length and separated the Pacific Plate to the west and the Farallon Plate to the east. It ran south from the Pacific-Farallon-Kula triple junction at 51°N to the Pacific-Farallon-Antarctic triple junction at 43°S. As the Farallon Plate subducted obliquely under the North American Plate, the Pacific-Farallon Ridge approached and eventually made contact with the North American Plate about 30 million years ago. On average, this ridge had an equatorial spreading rate of 13.5 cm per year until its eventual collision with the North American Plate. In present day, the Pacific-Farallon Ridge no longer formally exists since the Farallon Plate has been broken up or subducted beneath the North American Plate, and the ridge has segmented, having been mostly subducted as well. The most notable remnant of the Pacific-Farallon Ridge is the 4000 km Pacific-Nazca segment of the E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuamotu
The Tuamotu Archipelago or the Tuamotu Islands (french: Îles Tuamotu, officially ) are a French Polynesian chain of just under 80 islands and atolls in the southern Pacific Ocean. They constitute the largest chain of atolls in the world, extending (from northwest to southeast) over an area roughly the size of Western Europe. Their combined land area is . This archipelago's major islands are Anaa, Fakarava, Hao and Makemo. The Tuamotus have approximately 16,000 inhabitants. The islands were initially settled by Polynesians, and modern Tuamotuans have inherited from them a shared culture and the Tuamotuan language. The Tuamotus are a French overseas collectivity. History The early history of the Tuamotu islands is generally unknown. Archaeological findings suggest that the western Tuamotus were settled from the Society Islands as early as 900 CE or as late as 1200 CE. DNA evidence suggests that they were settled about 1110 CE. On the islands of Rangiroa, Manihi and Mataiva, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Islands
The Line Islands, Teraina Islands or Equatorial Islands (in Gilbertese, ''Aono Raina'') are a chain of 11 atolls (with partly or fully enclosed lagoons) and coral islands (with a surrounding reef) in the central Pacific Ocean, south of the Hawaiian Islands. The island chain stretches northwest to southeast across , making it one of the longest island chains in the world. It lies at the geographic center of the Pacific Ocean (), near Starbuck Island. One of the atolls in the group, Kiritimati, has the largest land area of any atoll in the world. Of the 11 atolls, all of which were formed by volcanic activity, only the Kiritimati and Tabuaeran atolls and Teraina island have a permanent population (one of the reefs, Filippo Reef, is shown on some maps, but its existence is doubted). Eight of the atolls are parts of Kiribati. The remaining three—Jarvis Island, Kingman Reef (which is largely submerged), and Palmyra Atoll—are territories of the United States grouped with the United ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Easter Hotspot
The Easter hotspot is a volcanic hotspot located in the southeastern Pacific Ocean. The hotspot created the Sala y Gómez Ridge which includes Easter Island, Salas y Gómez Island and the Pukao Seamount which is at the ridge's young western edge. Easter Island, because of its tectonomagmatic features (low eruptive rate, scattered rift zones, and scarce lateral collapses), represents an end-member type of hotspot volcano in this chain. The hotspot may also be responsible for the formation of the Tuamotu Archipelago, Line Islands, and the chain of seamounts lying in between. See also * Easter Island § Geology * Moai (seamount) The Moai Seamount is a submarine volcano, the second most westerly in the Easter Seamount Chain or Sala y Gómez ridge. It is east of Pukao seamount and west of Easter Island. It rises over 2,500 metres from the ocean floor to within a few hun ... References External links * Volcanism of Chile Hotspots of the Pacific Ocean Geograp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brisbane, Australia
Brisbane ( ) is the capital and most populous city of the Australian state of Queensland, and the third-most populous city in Australia and Oceania, with a population of approximately 2.6 million. Brisbane lies at the centre of the South East Queensland metropolitan region, which encompasses a population of around 3.8 million. The Brisbane central business district is situated within a peninsula of the Brisbane River about from its mouth at Moreton Bay, a bay of the Coral Sea. Brisbane is located in the hilly floodplain of the Brisbane River Valley between Moreton Bay and the Taylor and D'Aguilar mountain ranges. It sprawls across several local government areas, most centrally the City of Brisbane, Australia's most populous local government area. The demonym of Brisbane is ''Brisbanite''. The Traditional Owners of the Brisbane area include clans of the Yugara, Turrbal and Quandamooka peoples. The Turrbal word for the Brisbane area is ''Meeanjin''. The Moreton Bay p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwin Guyot
Darwin Guyot is a volcanic underwater mountain top, or guyot, in the Mid-Pacific Mountains between the Marshall Islands and Hawaii. Named after Charles Darwin, it rose above sea level more than 118 million years ago during the early Cretaceous period to become an atoll, developed Rudists, rudist reefs, and then drowned, perhaps as a consequence of sea level rise. The flat top of Darwin Guyot now rests below sea level. Name and research history The name ''Darwin Guyot'' was proposed in 1970 and accepted by the Board on Geographic Names shortly thereafter; it refers to Charles Darwin and the fact that unlike other guyots in the region it resembles an atoll. On the second voyage of the Beagle, in the 1830s, Darwin had theorised that as land rose, oceanic islands sank, and coral reefs round them grew to form atolls. It was dredged and surveyed in 1968 by the ship ; previously in the same year the had crossed over the guyot. Geography and geomorphology Darwin Guyot lies betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horizon Guyot
Horizon Guyot is a presumably Cretaceous guyot (tablemount) in the Mid-Pacific Mountains, Pacific Ocean. It is an elongated ridge, over long and high, that stretches in a northeast-southwest direction and has two flat tops; it rises to a minimum depth of . The Mid-Pacific Mountains lie west of Hawaii and northeast of the Line Islands. It was probably formed by a hotspot, but the evidence is conflicting. Volcanic activity occurred during the Turonian-Cenomanian eras 100.5–89.8 million years ago and another stage has been dated to have occurred 88–82 million years ago. Between these volcanic episodes, carbonate deposition from lagoonal and reefal environments set in and formed limestone. Volcanic islands developed on Horizon Guyot as well and were colonised by plants. Horizon Guyot became a seamount during the Coniacian-Campanian period. Since then, pelagic ooze has accumulated on the seamount, forming a thick layer that is further modified by ocean currents and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaiian–Emperor Seamount Chain
The Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific Ocean that reaches above sea level in Hawaii. It is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Seamounts: together they form a vast underwater mountain region of islands and intervening seamounts, atolls, shallows, banks and reefs along a line trending southeast to northwest beneath the northern Pacific Ocean. The seamount chain, containing over 80 identified undersea volcanoes, stretches about from the Aleutian Trench in the far northwest Pacific to the Kamaʻehuakanaloa Seamount (formerly Lōʻihi), the youngest volcano in the chain, which lies about southeast of the Island of Hawaiʻi. Regions The chain can be divided into three subsections. The first, the Hawaiian archipelago (also known as the ''Windward isles''), consists of the islands comprising the U.S. state of Hawaii. As it is the closest to the hots ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
