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Mariana Trench
The Mariana Trench is an oceanic trench located in the western Pacific Ocean, about east of the Mariana Islands; it is the deep sea, deepest oceanic trench on Earth. It is crescent-shaped and measures about in length and in width. The maximum known depth is at the southern end of a small slot-shaped valley in its floor known as the Challenger Deep. The deepest point of the trench is more than farther from sea level than the peak of Mount Everest. At the bottom of the trench, the water column above exerts a pressure of , more than 1,071 times the standard atmospheric pressure at sea level. At this pressure, the density of water is increased by 4.96%. The temperature at the bottom is . In 2009, the Mariana Trench was established as a National monument (United States), US National Monument, Mariana Trench Marine National Monument. One-celled organisms called monothalamea have been found in the trench at a record depth of below the sea surface by researchers from the Scrip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mariana Trench Marine National Monument
The Mariana Trench Marine National Monument is a United States National Monument (United States), National Monument created by President of the United States, President George W. Bush by the presidential proclamation no. 8335Presidential Proclamation no. 8335 January 6, 2009, ''Establishment of the Marianas Trench Marine National Monument''. on January 6, 2009. January 6, 2009 , January 6, 2009 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), the Pacific Ocean is the largest division of the World Ocean and the hydrosphere and covers approximately 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area ().Pacific Ocean . ''Encyclopædia Britannica, Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the Land and water hemispheres, water hemisphere and the Western Hemisphere, as well as the Pole of inaccessi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Microbes
A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in Jain literature authored in 6th-century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s, Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera, diphtheria, and anthrax. Microorganisms are extremely diverse, representing most unicellular organisms in all three domains of life: two of the three domains, Archaea and Bacteria, only contain microorganisms. The third domain, Eukaryota, includes all multicellular organisms as well as many unicellular protists and protozoans that ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Flux Melting
In igneous petrology and volcanology, flux melting occurs when water and other volatile components are introduced to hot solid rock, depressing the solidus. In engineering and metallurgy, flux is a substance, such as salt, that produces a low melting point ( liquidus) mixture with a metal oxide. In the same way, the addition of water and other volatile compounds to rocks composed of silicate minerals lowers the melting temperature ( solidus) of those rocks. In subduction zones, the ultramafic rock of the upper mantle is melted by the addition of volatiles from the subducting plate. The subducting oceanic crust carries water and other volatiles into the mantle, primarily in the form of hydrous minerals which form as a result of the interaction of oceanic crust and seawater. Bound in the subducting crust, these volatiles are released by metamorphic dewatering into the overlying mantle wedge. The partial melting triggered by the incorporation of volatiles produces mafic magma w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Oceanic Crust
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. The crust lies above the rigid uppermost layer of the mantle. The crust and the rigid upper mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however, it is denser, having a mean density of about 3.0 grams per cubic centimeter as opposed to continental crust which has a density of about 2.7 grams per cubic centimeter. The crust uppermost is the result of the cooling of magma derived from mantle material below the plate. The magma is injected into the spreading center, which consists mainly of a partly solidified crystal mush derive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mariana Plate
The Mariana plate is a micro tectonic plate located west of the Mariana Trench which forms the basement of the Mariana Islands which form part of the Izu–Bonin–Mariana Arc. It is separated from the Philippine Sea plate to the west by a divergent boundary with numerous transform fault offsets. The boundary between the Mariana and the Pacific plate to the east is a subduction zone with the Pacific plate subducting beneath the Mariana. This eastern subduction is divided into the Mariana Trench, which forms the southeastern boundary, and the Izu–Ogasawara Trench the northeastern boundary. The subduction plate motion is responsible for the shape of the Mariana plate and back arc. Geological history Subduction at the Mariana plate has been going on for over 50 million years. Some theories of the origin of this microplate is that when the Pacific plate began to subduct beneath the Philippine plate the volcanism and spreading ridge started to make an arc. This geological activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Tectonic Plate
Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called ''tectonics''. Tectonic plates also occur in other planets and moons. Earth's lithosphere, the rigid outer shell of the planet including the crust and upper mantle, is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault): , , or . The relative movement of the plates typically ranges from zero to 10 cm annually. Faults tend to be geologically active, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Convergent Boundary
A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a plane where many earthquakes occur, called the Wadati–Benioff zone. These collisions happen on scales of millions to tens of millions of years and can lead to volcanism, earthquakes, orogenesis, destruction of lithosphere, and deformation. Convergent boundaries occur between oceanic-oceanic lithosphere, oceanic-continental lithosphere, and continental-continental lithosphere. The geologic features related to convergent boundaries vary depending on crust types. Plate tectonics is driven by convection cells in the mantle. Convection cells are the result of heat generated by the radioactive decay of elements in the mantle escaping to the surface and the return of cool materials from the surface to the mantle. These convection cells bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Subduction
Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second plate, the heavier plate dives beneath the other 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 rates of convergence as high as 11 cm/year. Subduction is possible because the cold and rigid oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle. Once initiated, stable subduction is driven mostly by the negative buoyancy of the dense subducting lithosphere. The down-going slab sinks into the mantle largely under its own ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cross Section Of Mariana Trench
A cross is a religious symbol consisting of two Intersection (set theory), intersecting Line (geometry), lines, usually perpendicular to each other. The lines usually run vertically and horizontally. A cross of oblique lines, in the shape of the Latin letter X, is termed a saltire in heraldic terminology. The cross shape has been widely officially recognized as an absolute and exclusive religious symbol of Christianity from an early period in that religion's history.''Christianity: an introduction'' by Alister E. McGrath 2006 pages 321-323 Before then, it was used as a religious or cultural symbol throughout Europe, in West Asia, west and south Asia (the latter, in the form of the original Swastika); and in Ancient Egypt, where the Ankh was a hieroglyph that represented "life" and was used in the wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
