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Paleomagnetic Pole
Paleomagnetic poles or paleopoles are positions of the geomagnetic poles identified by the study of magnetic fields of the past as recorded in rocks and sediments. Robert F. Butler, ''PaleomagnetismMagnetic Domains to Geologic Terranes'', 1992Chapter 7: Paleomagnetic poles/ref>Dieke Gerritsen, Bram Vaes, Douwe J. J. van Hinsbergen"Influence of Data Filters on the Position and Precision of Paleomagnetic Poles: What Is the Optimal Sampling Strategy?" Determining paleomagnetic poles Theoretically, paleopoles could be located by measuring paleomagnetism in rocks of similar ages in different parts of the globe. However chronological dating is insufficiently precise for this purpose for remote paleographic eras. In addition, continental drift must be taken into an account. Only approximate locations can be assigned to paleopoles, with varying degree of reliability. Due to changing techniques and data selection and acceptance criteria, many "paleomagnetic poles" reported in the past wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomagnetic Pole
The geomagnetic poles are antipodal points where the axis of a best-fitting dipole intersects the surface of Earth. This ''theoretical'' dipole is equivalent to a powerful bar magnet at the center of Earth, and comes closer than any other point dipole model to describing the magnetic field observed at Earth's surface. In contrast, the magnetic poles of the actual Earth are not antipodal; that is, the line on which they lie does not pass through Earth's center. Owing to motion of fluid in the Earth's outer core, the actual magnetic poles are constantly moving (secular variation). However, over thousands of years, their direction averages to the Earth's rotation axis. On the order of once every half a million years, the poles reverse (i.e., north switches place with south) although the time frame of this switching can be anywhere from every 10 thousand years to every 50 million years. The poles also swing in an oval of around in diameter daily due to solar wind deflecting th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleomagnetism
Paleomagnetism (or palaeomagnetismsee ), is the study of magnetic fields recorded in rocks, sediment, or archeological materials. Geophysicists who specialize in paleomagnetism are called ''paleomagnetists.'' Certain magnetic minerals in rocks can record the direction and intensity of Earth's magnetic field at the time they formed. This record provides information on the past behavior of the geomagnetic field and the past location of tectonic plates. The record of geomagnetic reversals preserved in volcanic and sedimentary rock sequences (magnetostratigraphy) provides a time-scale that is used as a geochronologic tool. Evidence from paleomagnetism led to the revival of the continental drift hypothesis and its transformation into the modern theory of plate tectonics. Apparent polar wander paths provided the first clear geophysical evidence for continental drift, while marine magnetic anomalies did the same for seafloor spreading. Paleomagnetic data continues to extend th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert F
The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (''Hrōþiberhtaz''). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of ''Hrōþ, Hruod'' ( non, Hróðr) "fame, glory, honour, praise, renown" and ''berht'' "bright, light, shining"). It is the second most frequently used given name of ancient Germanic origin. It is also in use Robert (surname), as a surname. Another commonly used form of the name is Rupert (name), Rupert. After becoming widely used in Continental Europe it entered England in its Old French form ''Robert'', where an Old English cognate form (''Hrēodbēorht'', ''Hrodberht'', ''Hrēodbēorð'', ''Hrœdbœrð'', ''Hrœdberð'', ''Hrōðberχtŕ'') had existed before the Norman Conquest. The feminine version is Roberta (given name), Roberta. The Italian, Portuguese, and Spanish form is Roberto (given name), Roberto. Robert is also a common name in many Germanic languages, including English ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronological Dating
Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located in a previously established chronology. This usually requires what is commonly known as a "dating method". Several dating methods exist, depending on different criteria and techniques, and some very well known examples of disciplines using such techniques are, for example, history, archaeology, geology, paleontology, astronomy and even forensic science, since in the latter it is sometimes necessary to investigate the moment in the past during which the death of a cadaver occurred. These methods are typically identified as absolute, which involves a specified date or date range, or relative, which refers to dating which places artifacts or events on a timeline relative to other events and/or artifacts. Other markers can help place an artifact or event in a chronology, such as nearby writings and stratigraphic markers. Absolut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Drift
Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed. The idea of continental drift has been subsumed into the science of plate tectonics, which studies the movement of the continents as they ride on plates of the Earth's lithosphere. The speculation that continents might have 'drifted' was first put forward by Abraham Ortelius in 1596. A pioneer of the modern view of mobilism was the Austrian geologist Otto Ampferer.Helmut W. Flügel: Die virtuelle Welt des Otto Ampferer und die Realität seiner Zeit'. In: Geo. Alp., Vol. 1, 2004. The concept was independently and more fully developed by Alfred Wegener in 1912, but the hypothesis was rejected by many for lack of any motive mechanism. The English geologist Arthur Holmes later proposed mantle convection for that mechanism. History Early history Abraham Ortelius , Theodor Christoph Lilienthal (1756), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montana
Montana () is a U.S. state, state in the Mountain states, Mountain West List of regions of the United States#Census Bureau-designated regions and divisions, division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Provinces and territories of Canada, Canadian provinces of Alberta, British Columbia, and Saskatchewan to the north. It is the List of U.S. states and territories by area, fourth-largest state by area, the List of U.S. states and territories by population, eighth-least populous state, and the List of U.S. states and territories by population density, third-least densely populated state. Its state capital is Helena, Montana, Helena. The western half of Montana contains numerous mountain ranges, while the eastern half is characterized by western prairie terrain and badlands, with smaller mountain ranges found throughout the state. Montana has no official nickname but several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arizona
Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14th most populous of the 50 states. Its capital city, capital and List of largest cities, largest city is Phoenix, Arizona, Phoenix. Arizona is part of the Four Corners region with Utah to the north, Colorado to the northeast, and New Mexico to the east; its other neighboring states are Nevada to the northwest, California to the west and the List of states of Mexico, Mexican states of Sonora and Baja California (state), Baja California to the south and southwest. Arizona is the 48th state and last of the contiguous United States, contiguous states to be admitted to the Union, achieving statehood on February 14, 1912. Historically part of the territory of in New Spain, it became part of independent Mexico in 1821. After being defeated in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gringo Gulch
Gringo Gulch is a valley in Santa Cruz County, Arizona, in the United States. The valley's name is derived from the ethnonym gringo ''Gringo'' (, , ) (masculine) (or ''gringa'' (feminine)) is a term in Spanish and Portuguese for a foreigner, usually an English-speaking Anglo-American. There are differences in meaning depending on region and country. In Latin America, it is ge .... References {{coord, 31, 33, 56, N, 110, 46, 35, W, source:GNIS, display=title Landforms of Santa Cruz County, Arizona Valleys of Arizona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patagonia, Arizona
Patagonia is a town in Santa Cruz County, Arizona, United States. As of the 2010 census it had a population of 913. It developed in the mid-19th century as a trading and supply center for nearby mines and ranches. In the 21st century, it is a tourist destination, retirement community, and arts and crafts center. Geography The town is located in the valley of Sonoita Creek between the Santa Rita Mountains to the north and the Patagonia Mountains to the south. State route 82 passes through the town. Nogales lies to the southwest and Sonoita to the northeast. The former mining camps (now ghost towns) of Harshaw, Duquesne and Lochiel lie to the southeast along the eastern margin of the Patagonia Mountains. The high San Rafael Valley also lies to the southeast. Patagonia Lake State Park, around Patagonia Lake, lies about six miles southwest of the town. According to the United States Census Bureau, the town has a total area of , all land. History The area where Patagonia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Summary Style
World War II article in summary style World War II ... was a global war that was underway by 1939 and ended in 1945 .... The start of the war is generally held to be 1 September 1939 .... World War I radically altered the political map, with the defeat of the Central Powers .... The Second Italo–Abyssinian War was a brief colonial war that began in October 1935 and ended in May 1936 .... Germany and Italy lent support to the Spanish State, Nationalist insurrection led by general Francisco Franco in Spain .... Wikipedia articles cover topics at several levels of detail: the WP:LEAD, lead contains a quick summary of the topic's most important points, and each major subtopic is detailed in its own section of the article. The length of a given Wikipedia article tends to grow as people add information to it. Wikipedia articles cannot be of indefinite length as WP:SIZE, very long articles would cause problems and should be WP:SPLIT, split. A fuller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FORK
In cutlery or kitchenware, a fork (from la, furca ' pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tines with which one can spear foods either to hold them to cut with a knife or to lift them to the mouth. History Bone forks have been found in archaeological sites of the Bronze Age Qijia culture (2400–1900 BC), the Shang dynasty (c. 1600–c. 1050 BC), as well as later Chinese dynasties.Needham (2000). ''Science and Civilisation in China. Volume 6: Biology and biological technology. Part V: Fermentations and food science.'' Cambridge University Press. Pages 105–110. A stone carving from an Eastern Han tomb (in Ta-kua-liang, Suide County, Shaanxi) depicts three hanging two-pronged forks in a dining scene. Similar forks have also been depicted on top of a stove in a scene at another Eastern Han tomb (in Suide County, Shaanxi). In Ancient Egypt, large forks were u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Polar Wander
Apparent polar wander (APW) is the perceived movement of the Earth's paleo-magnetic poles relative to a continent while regarding the continent being studied as fixed in position. It is frequently displayed on the present latitude-longitude map as a path connecting the locations of geomagnetic poles, inferred at distinct times using paleomagnetic techniques. In reality, the relative polar movement can be either real polar wander or continental drift (or a combination of both). Data from around the globe are needed in order to isolate or distinguish between the two. Nevertheless, the magnetic poles rarely stray far from the geographic poles of the planet; rather they tend to follow true polar wander. Therefore, the concept of apparent polar wander is very useful in plate tectonics, since it can retrace the relative motion of continents, as well as the formation and break-up of supercontinents. History It has been known for a long time that the geomagnetic field varies through tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
