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Accretion (geology)
In geology, accretion is a process by which material is added to a tectonic plate at a subduction zone, frequently on the edge of existing continental landmasses. The added material may be sediment, volcanic arcs, seamounts, oceanic crust or other igneous features. Description Accretion involves the addition of material to a tectonic plate via subduction, the process by which one plate is forced under the other when two plates collide. The plate which is being forced down, the subducted plate, is pushed against the upper, over-riding plate. Sediment on the ocean floor of the subducting plate is often scraped off as the plate descends. This accumulated material is called an accretionary wedge (or accretionary prism), which is pushed against and attaches to the upper plate. In addition to accumulated ocean sediments, volcanic island arcs or seamounts present on the subducting plate may be amalgamated onto existing continental crust on the upper plate, increasing the contine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America 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 south and west by the Pacific Ocean. The region includes Middle America (Americas), Middle America (comprising the Caribbean, Central America, and Mexico) and Northern America. North America covers an area of about , representing approximately 16.5% of Earth's land area and 4.8% of its total surface area. It is the third-largest continent by size after Asia and Africa, and the list of continents and continental subregions by population, fourth-largest continent by population after Asia, Africa, and Europe. , North America's population was estimated as over 592 million people in list of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's popula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mediterranean Ridge
The Mediterranean Ridge is a wide ridge in the bed of the Mediterranean Sea, running along a rough quarter circle from Calabria, south of Crete, to the southwest corner of Turkey. It is an accretionary wedge caused by the African Plate subducting under the Eurasian and Anatolian plates. As the African Plate moves slowly north-northeastward, the sedimentary rocks covering the Mediterranean seafloor are being affected by active shortening, involving both thrust faulting and folding, lifting them up and forming the ridge. Along the ridge, five deep basins full of anoxic brine have been found (including the L'Atalante basin), where Messinian evaporite deposits of brine caught up in this ongoing orogeny have dissolved. Incipient collision with Africa The central section of the Mediterranean Ridge shows evidence for the initial stages of collision with the Cyrenaica Cyrenaica ( ) or Kyrenaika (, , after the city of Cyrene), is the eastern region of Libya. Cyrenaica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbados
Barbados, officially the Republic of Barbados, is an island country in the Atlantic Ocean. It is part of the Lesser Antilles of the West Indies and the easternmost island of the Caribbean region. It lies on the boundary of the South American Plate, South American and Caribbean Plate, Caribbean plates. Its capital and largest city is Bridgetown. Inhabited by Island Caribs, Kalinago people since the 13th century, and prior to that by other Indigenous peoples of the Americas, Indigenous peoples, Barbados was claimed for the Crown of Castile by Spanish navigators in the late 15th century. It first appeared on a Spanish map in 1511. The Portuguese Empire claimed the island between 1532 and 1536, but abandoned it in 1620 with their only remnants being the introduction of wild boars intended as a supply of meat whenever the island was visited. An Kingdom of England, English ship, the ''Olive Blossom'', arrived in Barbados on 14 May 1625; its men took possession of the island in the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philippine Sea Plate
The Philippine Sea plate or the Philippine plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of the Philippine Mobile Belt, which is geologically and tectonically separate from the Philippine Sea plate. The plate is bordered mostly by convergent boundaries: To the north, the Philippine Sea plate meets the Okhotsk microplate at the Nankai Trough. The Philippine Sea plate, the Amurian plate, and the Okhotsk plate meet near Mount Fuji in Japan. The thickened crust of the Izu–Bonin–Mariana arc colliding with Japan constitutes the Izu Collision Zone. The east of the plate includes the Izu– Ogasawara (Bonin) and the Mariana Islands, forming the Izu–Bonin–Mariana Arc system. There is also a divergent boundary between the Philippine Sea plate and the small Mariana plate which carries the Mariana Islands. To the east, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nankai Trough
The is a submarine trough located south of the Nankaidō region of Japan's island of Honshu, extending approximately offshore. The underlying fault, the ''Nankai megathrust,'' is the source of the devastating Nankai megathrust earthquakes, while the trough itself is potentially a major source of hydrocarbon fuel, in the form of methane clathrate. In plate tectonics, the Nankai Trough marks a subduction zone that is caused by subduction of the Philippine Sea plate beneath Japan, part of the Eurasian plate (Kanda et al., 2004). This plate boundary would be an oceanic trench except for a high flux of sediments that fills the trench. Within the Nankai Trough there is a large amount of deformed trench sediments (Ike, 2004), making one of Earth's best examples of accretionary prism. Furthermore, seismic reflection studies have revealed the presence of basement highs that are interpreted as seamounts that are covered in sediments (Ike, 2004). The northern part of the trough i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grenville Province
The Grenville Province is a tectonically complex region, in Eastern Canada, that contains many different aged Terrane, accreted terranes from various origins. It exists southeast of the Grenville Front Tectonic Zone, Grenville Front and extends from Labrador southwestern to Lake Huron. It is bounded by the Saint Lawrence River, St. Lawrence River/Saint Lawrence Seaway, Seaway to the southeast. The Grenville Front separates the Grenville Province from the Superior craton, Superior Craton. Adjacent to the Grenville Front is the Parautochthonous Belt. The Parautochthonous Belt is made of rocks originally derived from the Superior Craton, which have been metamorphosed and reworked since their emplacement. The rocks to the southwest of the Parautochthonous Belt are various Terrane, accreted terranes that have been thrust upon or emplaced during the various tectonic events that have taken place from 2.0 to 0.98 billion years ago. The compositions of these terranes are unique and have dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mazatzal Orogeny
The Mazatzal orogeny was an orogenic event in what is now the Southwestern United States from 1650 to 1600 Mya in the Statherian Period of the Paleoproterozoic. Preserved in the rocks of New Mexico and Arizona, it is interpreted as the collision of the 1700-1600 Mya age Mazatzal island arc terrane with the proto-North American continent. This was the second in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism. Description Age and isotope data show that southern North America is composed of a series of northeast-trending provinces representing island arc terranes accreted onto the 1800 Mya core of Laurentia. These are the Yavapai province (1800–1700 Mya), the Mazatzal province (1700–1650 Mya), the Granite-Rhyolite province (1500–1300 Mya), and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yavapai Orogeny
The Yavapai orogeny was an orogenic (mountain-building) event in what is now the Southwestern United States that occurred between 1710 and 1680 million years ago ( Mya), in the Statherian Period of the Paleoproterozoic. Recorded in the rocks of New Mexico and Arizona, it is interpreted as the collision of the 1800-1700 Mya age Yavapai island arc terrane with the proto-North American continent. This was the first in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism. Description Age and isotope data show that southern North America is composed of a series of northeast-trending provinces representing island arc terranes accreted onto the 1800 Mya core of Laurentia. These are the Yavapai province (1800–1700 Mya), the Mazatzal province (1700–1650 Mya), the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
