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Geomagnetic Reversals
A geomagnetic reversal is a change in the Earth's dipole magnetic field such that the positions of magnetic north and magnetic south are interchanged (not to be confused with geographic north and geographic south). The Earth's magnetic field has alternated between periods of ''normal'' polarity, in which the predominant direction of the field was the same as the present direction, and ''reverse'' polarity, in which it was the opposite. These periods are called '' chrons''. Reversal occurrences appear to be statistically random. There have been at least 183 reversals over the last 83 million years (thus on average once every ~450,000 years). The latest, the Brunhes–Matuyama reversal, occurred 780,000 years ago with widely varying estimates of how quickly it happened. Some sources estimate the most recent four reversals took on average 7,000 years to occur. Clement (2004) suggests that this duration is dependent on latitude, with shorter durations at low latitudes and lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomagnetic Polarity Late Cenozoic
Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from structure of Earth, Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo. The magnitude of Earth's magnetic field at its surface ranges from . As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11° with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of Earth. The North geomagnetic pole (Ellesmere Island, Nunavut, Canada) actually represents the South pole of Earth's magnetic field, and conversely the South geomagnetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allan V
Allan may refer to: People * Allan (given name), a list of people and characters with this given name * Allan (surname), a list of people and characters with this surname * Allan (footballer, born 1984) (Allan Barreto da Silva), Brazilian football striker * Allan (footballer, born 1989) (Allan dos Santos Natividade), Brazilian football forward * Allan (footballer, born 1991) (Allan Marques Loureiro), Brazilian football midfielder * Allan (footballer, born 1994) (Allan Christian de Almeida), Brazilian football midfielder * Allan (footballer, born 1997) (Allan Rodrigues de Souza), Brazilian football midfielder * Allan (footballer, born 2004) (Allan Andrade Elias), Brazilian football midfielder Places * Allan, Queensland, Australia * Allan, Saskatchewan, Canada * Allan Water (Ontario), a river * Allan, the Allaine river's lower course, in France * Allan, Drôme, town in France * Allan, Iran (other), places in Iran * Bridge of Allan, Central Scotland, a town o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harry Hammond Hess
Harry Hammond Hess (May 24, 1906 – August 25, 1969) was an American geologist and a United States Navy officer in World War II who is considered one of the "founding fathers" of the unifying theory of plate tectonics. He published theories on sea floor spreading, specifically on relationships between island arcs, seafloor gravity anomalies, and serpentinized peridotite, suggesting that the convection in the Earth's mantle is the driving force behind this process. Early life and education Harry Hammond Hess was born on May 24, 1906, in New York City to Julian S. Hess, a member of the New York Stock Exchange, and Elizabeth Engel Hess. He attended Asbury Park High School in Asbury Park, New Jersey. In 1923, he entered Yale University, where he intended to study electrical engineering but ended up graduating with a Bachelor of Science degree in geology. Hess failed his first time taking mineralogy at Yale and was told he had no future in the field. Despite this, he continued wi ... [...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] |
Drummond Matthews
Drummond Hoyle Matthews FRS (5 February 1931 – 20 July 1997), known as "Drum", was a British marine geologist and geophysicist and a key contributor to the theory of plate tectonics. His work, along with that of fellow Briton Fred Vine and Canadian Lawrence Morley, showed how variations in the magnetic properties of rocks forming the ocean floor could be consistent with, and ultimately help confirm, Harry Hammond Hess's 1962 theory of seafloor spreading. In 1989 he was awarded the Geological Society of London's highest honour, the Wollaston Medal. Early life During World War II he went to school at The Downs in Malvern, and then Bryanston School in Dorset. He became head boy at both. Career Alfred Wegener's theory of continental drift had never gained much scientific support due to its lack of any satisfactory mechanism to drive the process. During the 1950s, however, extensive surveys of the ocean floor revealed a global, linked system of mid-ocean ridges, all o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick 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 acts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic
Oceanic may refer to: *Of or relating to the ocean *Of or relating to Oceania **Oceanic climate **Oceanic languages **Oceanic person or people, also called "Pacific Islander(s)" Places * Oceanic, British Columbia, a settlement on Smith Island, British Columbia, Canada *Oceanic, New Jersey, an unincorporated community within Rumson Borough, Monmouth County, New Jersey, United States Ships named Oceanic * , the White Star Line's first ocean liner ** Oceanic-class ocean liner, class of liners based on SS ''Oceanic'' (1870) * , a transatlantic ocean liner built for the White Star Line * , a project of the 1930s * , built as SS ''Independence'' in 1950 * , also named ''Big Red Boat I'' by Premier Cruises Art, entertainment, and media Fictional entities * Oceanic Airlines or Oceanic Airways, often used in disaster movies * Oceanic Flight 815, a flight in the television series ''Lost'' Literature * "Oceanic" (novella), a 1998 sci-fi novella by Greg Egan Music ;Artists * Oceanic ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, one that measures the direction of an ambient magnetic field, in this case, the Earth's magnetic field. Other magnetometers measure the magnetic dipole moment of a magnetic material such as a ferromagnet, for example by recording the effect of this magnetic dipole on the induced current in a coil. The invention of the magnetometer is usually credited to Carl Friedrich Gauss in 1832. Earlier, more primitive instruments were developed by Christopher Hansteen in 1819, and by William Scoresby by 1823. Magnetometers are widely used for measuring the Earth's magnetic field, in geophysical surveys, to detect magnetic anomalies of various types, and to determine the dipole moment of magnetic materials. In an aircraft's attitude and heading ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamont–Doherty Earth Observatory
The Lamont-Doherty Earth Observatory (LDEO) is a research, research institution specializing in the Earth science and climate change. Though part of Columbia University, it is located on a separate closed campus in Palisades, New York. The observatory was one of the centers of research that led to the development of the theory of plate tectonics as well as many other notable scientific developments. Campus LDEO is located in Palisades, New York on a property overlooking the Hudson River which was once the weekend residence of banker Thomas W. Lamont. It was donated to the university in 1948 by his widow, Florence Lamont. In 1969, the Observatory was renamed "Lamont-Doherty" following a gift from the Henry L. and Grace Doherty Charitable Foundation. Research Climate change The LDEO is a substantial source of data for the US government in relation to climate change. Faculty at the LDEO have been noted for giving climate change testimony to United States Congress, Congr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neil D
Neil is a masculine name of Irish origin. The name is an anglicisation of the Irish '' Niall'' which is of disputed derivation. The Irish name may be derived from words meaning "cloud", "passionate", "victory", "honour" or "champion".. As a surname, Neil is traced back to Niall of the Nine Hostages who was an Irish king and eponymous ancestor of the Uí Néill and MacNeil kindred. Most authorities cite the meaning of Neil in the context of a surname as meaning "champion". Origins The Gaelic name was adopted by the Vikings and taken to Iceland as ''Njáll'' (see Nigel). From Iceland it went via Norway, Denmark, and Normandy to England. The name also entered Northern England and Yorkshire directly from Ireland, and from Norwegian settlers. ''Neal'' or ''Neall'' is the Middle English form of ''Nigel''. As a first name, during the Middle Ages, the Gaelic name of Irish origins was popular in Ireland and later Scotland. During the 20th century ''Neil'' began to be used in England and N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian National University
The Australian National University (ANU) is a public university, public research university and member of the Group of Eight (Australian universities), Group of Eight, located in Canberra, the capital of Australia. Its main campus in Acton, Australian Capital Territory, Acton encompasses seven teaching and research colleges, in addition to several national academies and institutes. Established in 1946, ANU is the only university to have been created by the Parliament of Australia. It traces its origins to Canberra University College, which was established in 1929 and was integrated into ANU in 1960. ANU enrols 13,329 undergraduate and 11,021 postgraduate students and employs 4,517 staff. The university's endowment stood at A$1.8 billion as of 2018. ANU counts six List of Nobel laureates, Nobel laureates and 49 Rhodes Scholarship, Rhodes scholars among its List of Australian National University people, faculty and alumni. The university has educated the incumbent Governor-Gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ian McDougall (geologist)
Ian McDougall (24 May 1935 – 10 November 2018) was an Australian geologist and geochemist. McDougall was born in Hobart and studied at the University of Tasmania and Australian National University, before taking up a research position at ANU. He was a Fellow of the Geological Society of America, the Australian Academy of Science, and the American Geophysical Union. McDougall also served as Vice President of the International Association of Volcanology and Chemistry of the Earth's Interior. McDougall's research areas included plate tectonics and geochronology Geochronology is the science of Chronological dating, determining the age of rock (geology), rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, .... He has been described as "one of Australia's most internationally distinguished earth scientists," and was awarded the Centenary Medal in 2001. McDougall died on 10 No ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
