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W. Jason Morgan
William Jason Morgan (October 10, 1935 – July 31, 2023) was an American geophysicist who made seminal contributions to the theory of plate tectonics and geodynamics. He retired as the Knox Taylor Professor emeritus of geology and professor of geosciences at Princeton University. He served as a visiting scholar in the Department of Earth and Planetary Sciences at Harvard University until his death. Early life and education Morgan was born on October 10, 1935, in Savannah, Georgia. His father William owned a hardware and dry goods store and his mother Maxie Ponita (Donehoo) Morgan was a French teacher and volunteered with the Girl Scouts of America. He attended Georgia Institute of Technology, initially studying mechanical engineering, but switched to physics halfway through his studies. He graduated in 1957. He was in the Navy for two years working as an instructor at its Nuclear Power School, which directed him toward graduate studies. In 1959, he went to Princeton Universit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George W
George Walker Bush (born July 6, 1946) is an American politician and businessman who was the 43rd president of the United States from 2001 to 2009. A member of the Bush family and the Republican Party (United States), Republican Party, he is the eldest son of the 41st president, George H. W. Bush, and was the 46th governor of Texas from 1995 to 2000. Bush flew warplanes in the Texas Air National Guard in his twenties. After graduating from Harvard Business School in 1975, he worked in the oil industry. He later co-owned the Major League Baseball team Texas Rangers (baseball), Texas Rangers before being elected governor of Texas 1994 Texas gubernatorial election, in 1994. Governorship of George W. Bush, As governor, Bush successfully sponsored legislation for tort reform, increased education funding, set higher standards for schools, and reformed the criminal justice system. He also helped make Texas the Wind power in Texas, leading producer of wind-generated electricity in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visiting Scholar
In academia, a visiting scholar, visiting scientist, visiting researcher, visiting fellow, visiting lecturer, or visiting professor is a scholar from an institution who visits a host university to teach, lecture, or perform research on a topic for which the visitor is valued. In many cases, the position is not salaried because the visitor is salaried by their home institution (or partially salaried, as in some cases of sabbatical leave from US universities). Some visiting positions are salaried. Typically, a visiting scholar may stay for a couple of months or even a year,UT"Visiting Scholar". The University of Texas at Austin. though the stay can be extended. A visiting scholar is usually invited by the host institution, and it is not out of the ordinary for them to provide accommodation. Such an invitation is often regarded as recognizing the scholar's prominence in the field. Attracting prominent visiting scholars often allows the permanent faculty and graduate students t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seamount
A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to in height. They are defined by oceanographers as independent features that rise to at least above the seafloor, characteristically of conical form.IHO, 2008. Standardization of Undersea Feature Names: Guidelines Proposal form Terminology, 4th ed. International Hydrographic Organization and Intergovernmental Oceanographic Commission, Monaco. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over geologic time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface. After they have subsided and sunk below the sea surface, such flat-top ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only state not on the North American mainland, the only state that is an archipelago, and the only state in the tropics. Hawaii consists of 137 volcanic islands that comprise almost the entire Hawaiian Islands, Hawaiian archipelago (the exception, which is outside the state, is Midway Atoll). Spanning , the state is Physical geography, physiographically and Ethnology, ethnologically part of the Polynesian subregion of Oceania. Hawaii's ocean coastline is consequently the List of U.S. states and territories by coastline, fourth-longest in the U.S., at about . The eight main islands, from northwest to southeast, are Niihau, Niihau, Kauai, Kauai, Oahu, Oahu, Molokai, Molokai, Lanai, Lānai, Kahoʻolawe, Kahoolawe, Maui, and Hawaii (island), Hawaii, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hotspot (geology)
In geology, hotspots (or hot spots) are volcanic locales thought to be fed by underlying Mantle (geology), mantle that is anomalously hot compared with the surrounding mantle. Examples include the Hawaii hotspot, Hawaii, Iceland hotspot, Iceland, and Yellowstone hotspots. A hotspot's position on the Earth's surface is independent of plate boundary, tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The alternative plate theory (volcanism), plate theory is that the mantle source beneath a hotspot is not anomalously hot, rather the crust above is unusually weak or thin, so that lithospheric extension permits the passive rising of melt from shallow depths. Origin The origins of the concept of hotspots lie in the work of J. Tuzo Wilson, who postulated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantle (geology)
A mantle is a layer inside a planetary body bounded below by a Planetary core, core and above by a Crust (geology), crust. Mantles are made of Rock (geology), rock or Volatile (astrogeology), ices, and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone planetary differentiation, differentiation by density. All Terrestrial planet, terrestrial planets (including Earth), half of the giant planets, specifically ice giants, a number of Asteroid, asteroids, and some planetary Natural satellite, moons have mantles. Examples Earth The Earth's mantle is a layer of Silicate minerals, silicate rock between the Crust (geology), crust and the Earth's outer core, 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 Geologic time scale, geological time it behaves as a Viscosity, visc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuzo Wilson
John Tuzo Wilson (October 24, 1908 – April 15, 1993) was a Canadian geophysicist and geologist who achieved worldwide acclaim for his contributions to the theory of plate tectonics. He added the concept of ''hot spots'', a volcanic region hotter than the surrounding mantle (as in the Hawaii hotspot). He also conceived of the ''transform fault'', a major plate boundary where two plates move past each other horizontally (''e.g.,'' the San Andreas Fault). His name was given to two young Canadian submarine volcanoes called the Tuzo Wilson Seamounts. The Wilson cycle of seabed expansion and contraction (associated with the Supercontinent cycle) bears his name. One of the two large low-shear-velocity provinces was given the name Tuzo after him, the other being named Jason after W. Jason Morgan, who furthered Wilson's work into plume theory. Early life and education Wilson was born in Ottawa on October 24, 1908, the son of John Armistead Wilson CBE, and his wife, Henrietta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantle Plume
A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps. Some such volcanic regions lie far from tectonic plate boundaries, while others represent unusually large-volume volcanism near plate boundaries. Concepts Mantle plumes were first proposed by J. Tuzo Wilson in 1963 and further developed by W. Jason Morgan in 1971 and 1972. A mantle plume is posited to exist where super-heated material forms ( nucleates) at the core-mantle boundary and rises through the Earth's mantle. Rather than a continuous stream, plumes should be viewed as a series of hot bubbles of material. Reaching the brittle upper Earth's crust they form diapirs. These diapirs are "hotspots" in the crust. In particular, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mid-ocean Ridge
A mid-ocean ridge (MOR) is a undersea mountain range, 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 boundary, 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 (geology), 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 oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry William Menard
Henry William Menard (December 10, 1920 – February 9, 1986) was an American geologist. Life and career He earned a B.S. and M.S. from the California Institute of Technology in 1942 and 1947, having served in the South Pacific during World War II as a photo interpreter. In 1949, he completed a Ph.D. in marine geology at Harvard University. Menard is perhaps best known for his promotion of the theory of plate tectonics before it was widely accepted in the scientific community. Menard served many roles during his career as a marine geologist. Field worker, theorist, educator, popularizer, entrepreneur and statesman. Menard's historical and sociological writings are respected by historians of science. Menard began his professional career in 1949, in the Sea Floor Studies Section of San Diego's Navy Electronics Laboratory. He joined the Scripps Institution of Oceanography (SIO) in 1955 as associate professor of geology. Menard's field work was extensive, involving 1,000 aqua-lung ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seafloor Spreading
Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener and Alexander du Toit of continental drift postulated that continents in motion "plowed" through the fixed and immovable seafloor. The idea that the seafloor itself moves and also carries the continents with it as it spreads from a central rift axis was proposed by Harold Hammond Hess from Princeton University and Robert Dietz of the U.S. Naval Electronics Laboratory in San Diego in the 1960s. The phenomenon is known today as plate tectonics. In locations where two plates move apart, at mid-ocean ridges, new seafloor is continually formed during seafloor spreading. Significance Seafloor spreading helps explain continental drift in the theory of plate tectonics. When oceanic plates diverge, tensional stress causes fractures to occur i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fred Vine
Frederick John Vine FRS (17 June 1939 – 21 June 2024) was an English marine geologist and geophysicist. He made key contributions to the theory of plate tectonics, helping to show that the seafloor spreads from mid-ocean ridges with a symmetrical pattern of magnetic reversals in the basalt rocks on either side. Early life Vine was born in Chiswick, London, and educated at Latymer Upper School and St John's College, Cambridge where he studied Natural Sciences (BA, 1962) and marine geophysics (PhD, 1965). He married Susan 'Sue' Vine (née McCall), who worked as a research assistant for Drummond Matthews in the Department of Geodesy and Geophysics, University of Cambridge, contributing to the development of the sea-floor spreading hypothesis associated with Matthews and her husband. Plate tectonics Vine's PhD thesis was on 'Magnetism in the Seafloor' and supervised by Drummond Matthews. Having met Harry Hess he was aware of sea floor spreading, where the ocean bed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
