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Trough (geology)
In geology, a trough is a linear structural depression that extends laterally over a distance. Although it is less steep than a ''trench'', a trough can be a narrow basin or a geologic rift. These features often form at the rim of tectonic plates. There are various oceanic troughs on the ocean floors. Examples of oceanic troughs * Benue Trough * Cayman Trough * Hesperides Trough * Kings Trough * Mariana Trough * Nankai Trough * Northumberland Trough * Okinawa Trough in the East China Sea * Rockall Trough and others along the rift of the mid-oceanic ridge * Salton Trough * South Shetland Trough * Suakin TroughDinwiddie, Robert et al. (2008) ''Ocean: The World's Last Wilderness Revealed'', London, Dorling Kindersley, page 452. in the Red Sea * Timor Trough See also * Oceanic basin * Thalweg * Walker Lane The Walker Lane is a geologic trough roughly aligned with the California/Nevada border southward to where Death Valley intersects the Garlock Fault, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cayman Trough
The Cayman Trough (also known as the Cayman Trench, Bartlett Deep and Bartlett Trough) is a complex transform fault zone pull-apart basin which contains a small spreading ridge, the Mid-Cayman Rise, on the floor of the western Caribbean Sea between Jamaica and the Cayman Islands. It is the deepest point in the Caribbean Sea and forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It extends from the Windward Passage, going south of the Sierra Maestra of Cuba toward Guatemala. The transform fault continues onshore as the Polochic-Motagua fault system, which consists of the Polochic and Motagua faults. This system continues on until the Chiapas massif where it is part of the diffuse triple junction of the North American, Caribbean and Cocos plates. The relatively narrow trough trends east-northeast to west-southwest and has a maximum depth of . Within the trough is a slowly spreading north–south ridge which may be the result of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northumberland Trough
The Northumberland Trough, also known as the Northumberland Basin, is an element of the structural geology of northern England, the origin of which dates back to the Carboniferous period when a block and basin province was established throughout the Pennine region. The trough is an ENE-WSW aligned half-graben, an asymmetric depositional basin. It is defined to the south by the Stublick and Ninety Fathom faults, which separate the trough from the Alston Block. To the north, where its depth is least, the trough's boundary with the Cheviot Block is less well-defined; nevertheless, the south-easterly down-throwing Featherwood and Alwinton faults can be identified along this margin. To the west, the trough is continuous with the Solway Basin. The surrounding blocks are buoyed up by granite batholiths maintaining these regions of the upper crust as areas of raised relief.British Geological Survey. 1996, ''Tectonic Map of Britain, Ireland & adjacent areas'', Pharaoh et al. 1:1500 00 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walker Lane
The Walker Lane is a geologic trough roughly aligned with the California/Nevada border southward to where Death Valley intersects the Garlock Fault, a major left lateral, or sinistral, strike-slip fault. The north-northwest end of the Walker Lane is between Pyramid Lake in Nevada and California's Lassen Peak where the Honey Lake Fault Zone, the Warm Springs Valley Fault, and the Pyramid Lake Fault Zone meet the transverse tectonic zone forming the southern boundary of the Modoc Plateau and Columbia Plateau provinces. The Walker Lane takes up 15 to 25 percent of the boundary motion between the Pacific plate and the North American plate, the other 75 percent being taken up by the San Andreas Fault system to the west. The Walker Lane may represent an incipient major transform fault zone which could replace the San Andreas as the plate boundary in the future. The Walker Lane deformation belt also accommodates nearly 12 mm/yr of dextral shear between the Sierra Nev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalweg
In geography, hydrography, and fluvial geomorphology, a thalweg or talweg () is the line or curve of lowest elevation within a valley or watercourse. Normally only the horizontal position of the curve is considered (as viewed on a map); the corresponding vertical position is represented in a '' stream profile''. Under international law, a thalweg is instead taken to be the middle of the primary navigable channel of a waterway which is the default legal presumption for the boundary between entities such as states. Thalwegs can have local proprietorial and administrative significance because their formerly somewhat shifting position, reliant on renewed soundings, now more fixed as described internationally, is part of centuries-old custom and practice in some jurisdictions. In some jurisdictions and between some states the median line (between banks) is the preferred boundary presumption as may extend from estuaries. Also being easy to map, drawing "turning points" are the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic Basin
In hydrology, an oceanic basin (or ocean basin) is anywhere on Earth that is covered by seawater. Geologically, most of the ocean basins are large Structural basin, geologic basins that are below sea level. Most commonly the ocean is divided into basins following the continents distribution: the Atlantic Ocean, North and South Atlantic (together approximately 75 million km2/ 29 million mi2), Pacific Ocean, North and South Pacific (together approximately 155 million km2/ 59 million mi2), Indian Ocean (68 million km2/ 26 million mi2) and Arctic Ocean (14 million km2/ 5.4 million mi2). Also recognized is the Southern Ocean (20 million km2/ 7 million mi2). All ocean basins collectively cover 71% of the Earth's surface, and together they contain almost 97% of all water on the planet. They have an average depth of almost 4 km (about 2.5 miles). Definitions of boundaries Boundaries based on continents ''"Limits of Oceans and Seas"'',International Hydrographic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timor Trough
The Timor Trough is an oceanic trough that is a continuation of the Sunda Trench (Java Trench) that marks the boundary between the Indo-Australian plate and the Timor plate. It is separated from the Sunda Trench by a sag near Sumba Island at the Scott Plateau and the North Australian Basin, and on the other end becomes the Tanimbar Trough southeast of the Tanimbar Islands, continuing on to the Aru Trough east of the Kai Islands near the Bird's Head Peninsula on New Guinea. Lining the north of the trough are numerous islands, of which Timor is the largest. Further west are the Weber Basin and the Banda Trench. Oil and natural gas Natural gas (also fossil gas, methane gas, and gas) is a naturally occurring compound of gaseous hydrocarbons, primarily methane (95%), small amounts of higher alkanes, and traces of carbon dioxide and nitrogen, hydrogen sulfide and helium ... have been found in the Bonaparte Basin south of the trough and the region is geologically active with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suakin Trough
Suakin or Sawakin (, Beja: ''Oosook'') is a port city in northeastern Sudan, on the west coast of the Red Sea. It was formerly the region's chief port, but is now secondary to Port Sudan, about north. Suakin used to be considered the height of medieval luxury on the Red Sea, but the old city built of coral is now in ruins. In 1983, the adjacent historic mainland town, known as the Geyf, had a population of 18,030 and the 2009 population was estimated at 43,337. Ferries run daily from Suakin to Jeddah in Saudi Arabia. Etymology The Beja name for Suakin is ''Oosook''. This is possibly from the Arabic word ''suq'', meaning market. In Beja, the locative case for this is ''isukib'', whence Suakin might have derived.Berg, RobertSuakin: Time and Tide. ''Saudi Aramco World.'' The spelling on Admiralty charts in the late 19th century was "Sauakin", but in the popular press "Suakim" was predominant. History Ancient Suakin was likely Ptolemy's Port of Good Hope, Limen Evangelis, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Shetland Trough
The South Shetland Trough is an undersea trough located north of the South Shetland Islands, which are a group of Antarctic islands. It is the remnant of a subduction zone where the defunct Phoenix Plate, now part of the Antarctic Plate, subducted under the Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martin in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica. ... and the South Shetland Islands. References Oceanic basins of the Southern Ocean Subduction zones {{marine-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salton Trough
The Salton Trough is an active tectonic pull-apart basin, or graben. It lies within the Imperial, Riverside, and San Diego counties of southeastern California and extends south of the Mexico–United States border into the state of Baja California. Description The Salton Trough is classified as a distinct section of the Basin and Range Province within the Intermontane Plateaus division. The northwestern end of the trough starts at the San Gorgonio Pass in Riverside County and extends southeast to the Gulf of California. Major geographical features located in the trough include the Coachella Valley, the Salton Sea, and the Imperial Valley, in the United States, and the western side of the Mexicali Valley and the Colorado River Delta in Mexico. At below sea level, the Salton Sink is the topographic low area within the Salton Trough and is the second-lowest point, after Death Valley, on the North American continent. At below sea level, the Salton Sea, which fills the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mid-oceanic Ridge
A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a divergent plate boundary. The rate of seafloor spreading determines the morphology of the crest of the mid-ocean ridge and its width in an ocean basin. The production of new seafloor and oceanic lithosphere results from mantle upwelling in response to plate separation. The melt rises as magma at the linear weakness between the separating plates, and emerges as lava, creating new oceanic crust and lithosphere upon cooling. The first discovered mid-ocean ridge was the Mid-Atlantic Ridge, which is a spreading center that bisects the North and South Atlantic basins; hence the origin of the name 'mid-ocean ridge'. Most oceanic spreading centers are not in the middle of their hosting ocean basis but regardless, are traditionally called mid-o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Okinawa Trough
The (also called , literally "China-Ryukyu Border Trough") is a seabed feature of the East China Sea. It is an active, initial back-arc rifting basin which has formed behind the Ryukyu arc-trench system in the West Pacific. It developed where the Philippine Sea Plate is subducting under the Eurasia Plate. Description It is a back-arc basin formed by extension within the continental lithosphere behind the far deeper Ryukyu Trench-arc system. The thickness of the crust in the northern Okinawa Trough is 30 km, thinning to 10 km in the southern Okinawa Trough. It has a large section more than deep and a maximum depth of . The Okinawa Trough still in an early stage of evolving from arc type to back-arc activity, and features volcanoes such as the Yonaguni Knoll IV. Implications for the China–Japan maritime boundary Interpretations The existence of the Okinawa Trough complicates descriptive issues in the East China Sea.Ji, Guoxing. (1995) "Maritime Jurisdiction in t ... [...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] |
