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Antarctic Plate
The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the supercontinent Pangea), the Antarctic plate began moving the continent of Antarctica south to its present isolated location, causing the continent to develop a much colder climate. The Antarctic Plate is bounded almost entirely by extensional mid-ocean ridge systems. The adjoining plates are the Nazca Plate, the South American Plate, the African Plate, the Somali Plate, the Indo-Australian Plate, the Pacific Plate, and, across a transform boundary, the Scotia Plate. The Antarctic Plate has an area of about . It is Earth's fifth-largest tectonic plate. The Antarctic Plate's movement is estimated to be at least per year towards the Atlantic Ocean. Subduction beneath South America The Antarctic Plate started to subduct beneath South America 14 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Tectonic Plates
This is a list of tectonic plates on Earth's surface. Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around thick and consist of two principal types of material: oceanic crust (also called '' sima'' from silicon and magnesium) and continental crust (''sial'' from silicon and aluminium). The composition of the two types of crust differs markedly, with mafic basaltic rocks dominating oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks. Current plates Geologists generally agree that the following tectonic plates currently exist on Earth's surface with roughly definable boundaries. Tectonic plates are sometimes subdivided into three fairly arbitrary categories: ''major'' (or ''primary'') ''plates'', ''minor'' (or ''secondary'') ''plates'', and ''microplates'' (or ''tertiary plates''). Major plates These plates comprise the bulk of the continents an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and Izanagi Plates. The Pacific Plate subsequently grew to where it underlies most of the Pacific Ocean basin. This reduced the Farallon Plate to a few remnants along the west coast of North America and the Phoenix Plate to a small remnant near the Drake Passage, and destroyed the Izanagi Plate by subduction under Asia. The Pacific Plate contains an interior hot spot forming the Hawaiian Islands. Boundaries The north-eastern side is a divergent boundary with the Explorer Plate, the Juan de Fuca Plate and the Gorda Plate forming respectively the Explorer Ridge, the Juan de Fuca Ridge and the Gorda Ridge. In the middle of the eastern side is a transform boundary with the North American Plate along the San Andreas Fault, and a boundary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Topography
The term dynamic topography is used in geodynamics to refer the elevation differences caused by the flow within Earth's mantle. Definition In geodynamics, ''dynamic topography'' refers to topography generated by the motion of zones of differing degrees of buoyancy (convection) in Earth's mantle. It is also seen as the residual topography obtained by removing the isostatic contribution from the observed topography (i.e., the topography that cannot be explained by an isostatic equilibrium of the crust or the lithosphere resting on a fluid mantle) and all observed topography due to post-glacial rebound. Elevation differences due to dynamic topography are frequently on the order of a few hundred meters to a couple of kilometers. Large scale surface features due to dynamic topography are mid-ocean ridges and oceanic trenches. Other prominent examples include areas overlying mantle plumes such as the African superswell. The mid-ocean ridges are high due to dynamic topography becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantle (geology)
A mantle is a layer inside a planetary body bounded below by a core and above by a crust. Mantles are made of rock or ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by density. All terrestrial planets (including Earth), a number of asteroids, and some planetary moons have mantles. Earth's mantle The Earth's mantle is a layer of silicate rock between the crust and the 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 geological time it behaves as a viscous fluid. Partial melting of the mantle at mid-ocean ridges produces oceanic crust, and partial melting of the mantle at subduction zones produces continental crust. Other planetary mantles Mercury has a silicate mantle approximately thick, constituting only 28% of its ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patagonia
Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and glaciers in the west and deserts, tablelands and steppes to the east. Patagonia is bounded by the Pacific Ocean on the west, the Atlantic Ocean to the east, and many bodies of water that connect them, such as the Strait of Magellan, the Beagle Channel, and the Drake Passage to the south. The Colorado and Barrancas rivers, which run from the Andes to the Atlantic, are commonly considered the northern limit of Argentine Patagonia. The archipelago of Tierra del Fuego is sometimes included as part of Patagonia. Most geographers and historians locate the northern limit of Chilean Patagonia at Huincul Fault, in Araucanía Region.Manuel Enrique Schilling; Richard WalterCarlson; AndrésTassara; Rommulo Vieira Conceição; Gustavo Walter Berto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taitao Peninsula
The Taitao Peninsula (Spanish: ''Península de Taitao'') is a westward projection of the mainland of Chile, with which it is connected by the narrow Isthmus of Ofqui, over which the natives and early missionaries were accustomed to carry their boats between the Moraleda Channel and Gulf of Penas. spelled "Taytao" It is situated in the Aysén del General Carlos Ibáñez del Campo Region and a part of this peninsula is located inside the boundaries of Laguna San Rafael National Park. The Presidente Ríos Lake, with a surface area of , lies in the middle of the peninsula. A southward incurving projection of the outer shoreline of this peninsula is known as Tres Montes peninsula, the most southern point of which is a cape of the same name. Spanish explorers and Jesuits that sailed south from Chiloé Archipelago in the 17th and 18th centuries regularly avoided rounding Taitao Peninsula entering instead the Gulf of Penas after a brief land crossing at the isthmus of Ofqui. While at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chile Ridge
The Chile Ridge, also known as the Chile Rise, is a submarine oceanic ridge formed by the divergent plate boundary between the Nazca Plate and the Antarctic Plate. It extends from the triple junction of the Nazca, Pacific, and Antarctic plates to the Southern coast of Chile. The Chile Ridge is easy to recognize on the map, as the ridge is divided into several segmented fracture zones which are perpendicular to the ridge segments, showing an orthogonal shape toward the spreading direction. The total length of the ridge segments is about 550–600 km. The continuously spreading Chile Ridge collides with the southern South America Plate to the east, and the ridge has been subducting underneath the Taitao Peninsula since 14 million years ago (Ma). The ridge-collision has generated a slab window beneath the overlying South America Plate, with smaller volume of upper mantle magma melt, proven by an abrupt low velocity of magma flow rate below the separating Chile ridge. The subduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strait Of Magellan
The Strait of Magellan (), also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and Tierra del Fuego to the south. The strait is considered the most important natural passage between the Atlantic and Pacific oceans. It was discovered and first traversed by the Spanish expedition of Ferdinand Magellan in 1520, after whom it is named. Prior to this, the strait had been navigated by canoe-faring indigenous peoples including the Kawésqar. Magellan's original name for the strait was ''Estrecho de Todos los Santos'' ("Strait of All Saints"). The King of Spain, Emperor Charles V, who sponsored the Magellan-Elcano expedition, changed the name to the Strait of Magellan in honor of Magellan. The route is difficult to navigate due to frequent narrows and unpredictable winds and currents. Maritime piloting is now compulsory. The strait is shorter and more sheltered than the Drake Passage, the often stor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chile Triple Junction
The Chile Triple Junction (or Chile Margin Triple Junction) is a geologic triple junction located on the seafloor of the Pacific Ocean off Taitao and Tres Montes Peninsula on the southern coast of Chile. Here three tectonic plates meet: the South American Plate, the Nazca Plate and the Antarctic Plate. This triple junction is unusual in that it consists of a mid-oceanic ridge, the Chile Rise, being subducted under the South American Plate at the Peru–Chile Trench. The Chile Triple Junction is the boundary between the Chilean Rise and the Chilean margin, where the Nazca, Antarctic, and South American plates meet at the trench. Tectonic plate movement The Antarctic Plate started to subduct beneath South America 14 million years ago in the Miocene epoch forming the Chile Triple Junction. At first the Antarctic Plate subducted only in the southernmost tip of Patagonia, meaning that the Chile Triple Junction lay near the Strait of Magellan. As the southern part of Nazca Plate and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tectonic Evolution Of Patagonia
Patagonia comprises the southernmost region of South America, portions of which lie on either side of the Argentina-Chile border. It has traditionally been described as the region south of the Rio Colorado, although the physiographic border has more recently been moved southward to the Huincul fault. The region's geologic border to the north is composed of the Rio de la Plata craton and several accreted terranes comprising the La Pampa province. The underlying basement rocks of the Patagonian region can be subdivided into two large massifs: the North Patagonian Massif and the Deseado Massif. These massifs are surrounded by sedimentary basins formed in the Mesozoic that underwent subsequent deformation during the Andean orogeny. Patagonia is known for its vast earthquakes and the damage they cause. The rocks comprising Patagonia occurred along the southwestern margin of the ancient supercontinent of Gondwana. During a period of continental rifting in the Cambrian period, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Subduction is possible because the cold oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle underlying the cold, rigid lithosphere. Once initiated, stable subduction is driven mostly by the negative buoyancy of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
