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Europe
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Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, yet the non-oceanic borders of Europe—a concept dating back to classical antiquity—are arbitrary. Europe covers about 10,180,000 square kilometres, or 2% of the Earths surface, politically, Europe is divided into about fifty sovereign states of which the Russian Federation is the largest and most populous, spanning 39% of the continent and comprising 15% of its population. Europe had a population of about 740 million as of 2015. Further from the sea, seasonal differences are more noticeable than close to the coast, Europe, in particular ancient Greece, was the birthplace of Western civilization. The fall of the Western Roman Empire, during the period, marked the end of ancient history. Renaissance humanism, exploration, art, and science led to the modern era, from the Age of Discovery onwards, Europe played a predominant role in global affairs. Between the 16th and 20th centuries, European powers controlled at times the Americas, most of Africa, Oceania. The Industrial Revolution, which began in Great Britain at the end of the 18th century, gave rise to economic, cultural, and social change in Western Europe. During the Cold War, Europe was divided along the Iron Curtain between NATO in the west and the Warsaw Pact in the east, until the revolutions of 1989 and fall of the Berlin Wall. In 1955, the Council of Europe was formed following a speech by Sir Winston Churchill and it includes all states except for Belarus, Kazakhstan and Vatican City. Further European integration by some states led to the formation of the European Union, the EU originated in Western Europe but has been expanding eastward since the fall of the Soviet Union in 1991. The European Anthem is Ode to Joy and states celebrate peace, in classical Greek mythology, Europa is the name of either a Phoenician princess or of a queen of Crete. The name contains the elements εὐρύς, wide, broad and ὤψ eye, broad has been an epithet of Earth herself in the reconstructed Proto-Indo-European religion and the poetry devoted to it. For the second part also the divine attributes of grey-eyed Athena or ox-eyed Hera. The same naming motive according to cartographic convention appears in Greek Ανατολή, Martin Litchfield West stated that phonologically, the match between Europas name and any form of the Semitic word is very poor. Next to these there is also a Proto-Indo-European root *h1regʷos, meaning darkness. Most major world languages use words derived from Eurṓpē or Europa to refer to the continent, in some Turkic languages the originally Persian name Frangistan is used casually in referring to much of Europe, besides official names such as Avrupa or Evropa
2.
Asia
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Asia covers an area of 44,579,000 square kilometres, about 30% of Earths total land area and 8. 7% of the Earths total surface area. The continent, which has long been home to the majority of the population, was the site of many of the first civilizations. Asia is notable for not only its large size and population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, the western boundary with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. The most commonly accepted boundaries place Asia to the east of the Suez Canal, the Ural River, and the Ural Mountains, and south of the Caucasus Mountains, China and India alternated in being the largest economies in the world from 1 to 1800 A. D. The accidental discovery of America by Columbus in search for India demonstrates this deep fascination, the Silk Road became the main East-West trading route in the Asian hitherland while the Straits of Malacca stood as a major sea route. Asia has exhibited economic dynamism as well as robust population growth during the 20th century, given its size and diversity, the concept of Asia—a name dating back to classical antiquity—may actually have more to do with human geography than physical geography. Asia varies greatly across and within its regions with regard to ethnic groups, cultures, environments, economics, historical ties, the boundary between Asia and Africa is the Red Sea, the Gulf of Suez, and the Suez Canal. This makes Egypt a transcontinental country, with the Sinai peninsula in Asia, the border between Asia and Europe was historically defined by European academics. In Sweden, five years after Peters death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Urals as the border of Asia, the Russians were enthusiastic about the concept, which allowed them to keep their European identity in geography. Tatishchev announced that he had proposed the idea to von Strahlenberg, the latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th century, the border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is usually placed along the crest of the Caucasus Mountains, the border between Asia and the loosely defined region of Oceania is usually placed somewhere in the Malay Archipelago. The terms Southeast Asia and Oceania, devised in the 19th century, have had several different geographic meanings since their inception. The chief factor in determining which islands of the Malay Archipelago are Asian has been the location of the possessions of the various empires there. Lewis and Wigen assert, The narrowing of Southeast Asia to its present boundaries was thus a gradual process, Asia is larger and more culturally diverse than Europe. It does not exactly correspond to the borders of its various types of constituents. From the time of Herodotus a minority of geographers have rejected the three-continent system on the grounds there is no or is no substantial physical separation between them
3.
Atlantic Ocean
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The Atlantic Ocean is the second largest of the worlds oceans with a total area of about 106,460,000 square kilometres. It covers approximately 20 percent of the Earths surface and about 29 percent of its surface area. It separates the Old World from the New World, the Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Eurasia and Africa to the east, and the Americas to the west. The Equatorial Counter Current subdivides it into the North Atlantic Ocean, in contrast, the term Atlantic originally referred specifically to the Atlas Mountains in Morocco and the sea off the Strait of Gibraltar and the North African coast. The Greek word thalassa has been reused by scientists for the huge Panthalassa ocean that surrounded the supercontinent Pangaea hundreds of years ago. The term Aethiopian Ocean, derived from Ancient Ethiopia, was applied to the Southern Atlantic as late as the mid-19th century, many Irish or British people refer to the United States and Canada as across the pond, and vice versa. The Black Atlantic refers to the role of ocean in shaping black peoples history. Irish migration to the US is meant when the term The Green Atlantic is used, the term Red Atlantic has been used in reference to the Marxian concept of an Atlantic working class, as well as to the Atlantic experience of indigenous Americans. Correspondingly, the extent and number of oceans and seas varies, the Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea, Norwegian Sea, to the east, the boundaries of the ocean proper are Europe, the Strait of Gibraltar and Africa. In the southeast, the Atlantic merges into the Indian Ocean, the 20° East meridian, running south from Cape Agulhas to Antarctica defines its border. In the 1953 definition it extends south to Antarctica, while in later maps it is bounded at the 60° parallel by the Southern Ocean, the Atlantic has irregular coasts indented by numerous bays, gulfs, and seas. Including these marginal seas the coast line of the Atlantic measures 111,866 km compared to 135,663 km for the Pacific. Including its marginal seas, the Atlantic covers an area of 106,460,000 km2 or 23. 5% of the ocean and has a volume of 310,410,900 km3 or 23. 3%. Excluding its marginal seas, the Atlantic covers 81,760,000 km2 and has a volume of 305,811,900 km3, the North Atlantic covers 41,490,000 km2 and the South Atlantic 40,270,000 km2. The average depth is 3,646 m and the maximum depth, the bathymetry of the Atlantic is dominated by a submarine mountain range called the Mid-Atlantic Ridge. It runs from 87°N or 300 km south of the North Pole to the subantarctic Bouvet Island at 42°S, the MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR reaches above 2000 m along most of its length, the MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other
4.
Arctic Ocean
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The Arctic Ocean is the smallest and shallowest of the worlds five major oceans. Alternatively, the Arctic Ocean can be seen as the northernmost part of the all-encompassing World Ocean, located mostly in the Arctic north polar region in the middle of the Northern Hemisphere, the Arctic Ocean is almost completely surrounded by Eurasia and North America. It is partly covered by sea ice throughout the year and almost completely in winter, the summer shrinking of the ice has been quoted at 50%. The US National Snow and Ice Data Center uses satellite data to provide a record of Arctic sea ice cover. The Arctic may become ice free for the first time in human history within a few years or by 2040, for much of European history, the north polar regions remained largely unexplored and their geography conjectural. He was probably describing loose sea ice known today as growlers or bergy bits, his Thule was probably Norway, early cartographers were unsure whether to draw the region around the North Pole as land or water. The makers of navigational charts, more conservative than some of the more fanciful cartographers, tended to leave the region blank and this lack of knowledge of what lay north of the shifting barrier of ice gave rise to a number of conjectures. In England and other European nations, the myth of an Open Polar Sea was persistent, john Barrow, longtime Second Secretary of the British Admiralty, promoted exploration of the region from 1818 to 1845 in search of this. In the United States in the 1850s and 1860s, the explorers Elisha Kane, even quite late in the century, the eminent authority Matthew Fontaine Maury included a description of the Open Polar Sea in his textbook The Physical Geography of the Sea. Nevertheless, as all the explorers who travelled closer and closer to the reported, the polar ice cap is quite thick. Fridtjof Nansen was the first to make a crossing of the Arctic Ocean. The first surface crossing of the ocean was led by Wally Herbert in 1969, in a dog sled expedition from Alaska to Svalbard, with air support. The first nautical transit of the pole was made in 1958 by the submarine USS Nautilus. Since 1937, Soviet and Russian manned drifting ice stations have extensively monitored the Arctic Ocean, scientific settlements were established on the drift ice and carried thousands of kilometres by ice floes. In World War II, the European region of the Arctic Ocean was heavily contested, the Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km2, almost the size of Antarctica. The coastline is 45,390 km long and it is surrounded by the land masses of Eurasia, North America, Greenland, and by several islands. It is connected to the Pacific Ocean by the Bering Strait and to the Atlantic Ocean through the Greenland Sea, countries bordering the Arctic Ocean are, Russia, Norway, Iceland, Greenland, Canada and the United States. There are several ports and harbours around the Arctic Ocean In Alaska, in Canada, ships may anchor at Churchill in Manitoba, Nanisivik in Nunavut, Tuktoyaktuk or Inuvik in the Northwest territories
5.
African Plate
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The African Plate is a major tectonic plate straddling the equator as well as the prime meridian. It includes much of the continent of Africa, as well as oceanic crust which lies between the continent and various surrounding ocean ridges, between 60 million years ago and 10 million years ago, the Somali Plate began rifting from the African Plate along the East African Rift. All of these are divergent or spreading boundaries with the exception of the northern boundary, the cratons are, from south to north, the Kalahari craton, Congo craton, Tanzania craton and West African craton. The cratons were widely separated in the past, but came together during the Pan-African orogeny, the cratons are connected by orogenic belts, regions of highly deformed rock where the tectonic plates have engaged. The African Plate is rifting in the interior of the African continent along the East African Rift. This rift zone separates the African Plate to the west from the Somali Plate to the east, the African Plates speed is estimated at around 2.15 cm per year. It has been moving over the past 100 million years or so in a general northeast direction and this is drawing it closer to the Eurasian Plate, causing subduction where oceanic crust is converging with continental crust. Along its northeast margin, the African Plate is bounded by the Red Sea Rift where the Arabian Plate is moving away from the African Plate. The New England hotspot in the Atlantic Ocean has probably created a line of mid- to late-Tertiary age seamounts on the African Plate. USGS - Understanding plate motions Meijer, P. Th, wortel, M. J. R. Cenozoic dynamics of the African plate with emphasis on the Africa-Eurasia collision. Journal of Geophysical Research, Solid Earth
6.
Plate tectonics
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The theoretical model builds on the concept of continental drift developed during the first few decades of the 20th century. The geoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s, the lithosphere, which is the rigid outermost shell of a planet, is broken up into tectonic plates. The Earths lithosphere is composed of seven or eight major plates, where the plates meet, their relative motion determines the type of boundary, convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The relative movement of the plates typically ranges from zero to 100 mm annually, tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle, the material lost is balanced by the formation of new crust along divergent margins by seafloor spreading. In this way, the surface of the lithosphere remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle, earlier theories, since disproven, proposed gradual shrinking or gradual expansion of the globe. Tectonic plates are able to move because the Earths lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the ridge and drag, with downward suction. Another explanation lies in the different forces generated by forces of the Sun. The relative importance of each of these factors and their relationship to other is unclear. The outer layers of the Earth are divided into the lithosphere and asthenosphere and this is based on differences in mechanical properties and in the method for the transfer of heat. Mechanically, the lithosphere is cooler and more rigid, while the asthenosphere is hotter, in terms of heat transfer, the lithosphere loses heat by conduction, whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, Plate motions range up to a typical 10–40 mm/year, to about 160 mm/year. The driving mechanism behind this movement is described below, tectonic lithosphere plates consist of lithospheric mantle overlain by either or both of two types of crustal material, oceanic crust and continental crust. Average oceanic lithosphere is typically 100 km thick, its thickness is a function of its age, as passes, it conductively cools
7.
Eurasia
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Eurasia /jʊˈreɪʒə/ is a combined continental landmass of Europe and Asia. The term is a portmanteau of its constituent continents, in geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on the paleomagnet data, Eurasia covers around 55,000,000 square kilometres, or around 36. 2% of the Earths total land area. The landmass contains around 5.0 billion people, equating to approximately 70% of the human population, humans first settled in Eurasia between 60,000 and 125,000 years ago. Physiographically, Eurasia is a single continent, the concepts of Europe and Asia as distinct continents date back to antiquity and their borders are geologically arbitrary. Eurasia is connected to Africa at the Suez Canal, and Eurasia is sometimes combined with Africa as the largest contiguous landmass on Earth called Afro-Eurasia. Eurasia formed 375 to 325 million years ago with the merging of Siberia, Kazakhstania, and Baltica, chinese cratons collided with Siberias southern coast. Eurasia has been the host of ancient civilizations, including those based in Mesopotamia. In the Axial Age, a belt of civilizations stretched through the Eurasian subtropical zone from the Atlantic to the Pacific. This belt became the mainstream of world history for two millennia, originally, “Eurasia” is a geographical notion, in this sense, it is simply the biggest continent, the combined landmass of Europe and Asia. However, geopolitically, the word has different meanings, reflecting the specific geopolitical interests of each nation. “Eurasia” is one of the most important geopolitical concepts, as Zbigniew Brzezinski observed, how America manages Eurasia is critical. A power that dominates “Eurasia” would control two of the three most advanced and economically productive regions. About 75 per cent of the people live in “Eurasia”. “Eurasia” accounts for about three-fourths of the known energy resources. ”At the moment one of the most prominent projects of the European Union is the Russia - EU Four Common Spaces Initiative. A political and economic union of former Soviet states named the Eurasian Economic Union was established in 2015, the Russian concept of “Eurasia” corresponded initially more or less to the land area of Imperial Russia in 1914, including parts of Eastern Europe. One of Russias main geopolitical interests lies in ever closer integration with those countries that it considers part of “Eurasia. ”Every two years since 1996 a meeting of most Asian and European countries is organised as the Asia-Europe Meeting. In ancient times, the Greeks classified Europe and Asia as separate lands, where to draw the dividing line between the two regions is still a matter of discussion
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Continent
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A continent is one of several very large landmasses on Earth. Generally identified by convention rather than any strict criteria, up to seven regions are regarded as continents. Ordered from largest in size to smallest, they are, Asia, Africa, North America, South America, Antarctica, Europe, in geology, areas of continental crust include regions covered with water. Islands are frequently grouped with a continent to divide all the worlds land into geopolitical regions. Under this scheme, most of the countries and territories in the Pacific Ocean are grouped together with the continent of Australia to form a geopolitical region called Oceania. By convention, continents are understood to be large, continuous, discrete masses of land, many of the seven most commonly recognized continents identified by convention are not discrete landmasses separated completely by water. Earths major landmasses all have coasts on a single, continuous World Ocean, the most restricted meaning of continent is that of a continuous area of land or mainland, with the coastline and any land boundaries forming the edge of the continent. From this perspective the edge of the shelf is the true edge of the continent. In this sense the islands of Great Britain and Ireland are part of Europe, while Australia, as a cultural construct, the concept of a continent may go beyond the continental shelf to include oceanic islands and continental fragments. In this way, Iceland is considered part of Europe and Madagascar part of Africa, extrapolating the concept to its extreme, some geographers group the Australasian continental plate with other islands in the Pacific into one continent called Oceania. This divides the land surface of Earth into continents or quasi-continents. The ideal criterion that each continent be a discrete landmass is commonly relaxed due to historical conventions, of the seven most globally recognized continents, only Antarctica and Australia are completely separated from other continents by ocean. Several continents are defined not as absolutely distinct bodies but as more or less discrete masses of land, Asia and Africa are joined by the Isthmus of Suez, and North and South America by the Isthmus of Panama. In both cases, there is no separation of these landmasses by water. Both these isthmuses are very narrow compared to the bulk off the landmasses they unite, North America and South America are treated as separate continents in the seven-continent model. However, they may also be viewed as a continent known as America or the Americas. This viewpoint was common in the United States until World War II and this remains the more common vision in Latin American countries, Spain, Portugal, France, Italy and Greece, where they are taught as a single continent. The criterion of a landmass is completely disregarded if the continuous landmass of Eurasia is classified as two separate continents, Europe and Asia
9.
Indian subcontinent
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Geologically, the Indian subcontinent is related to the land mass that rifted from Gondwana and merged with the Eurasian plate nearly 55 million years ago. Geographically, it is the region in south-central Asia delineated by the Himalayas in the north, the Hindu Kush in the west. Politically, the Indian subcontinent usually includes Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, sometimes, the term South Asia is used interchangeably with Indian subcontinent. There is no consensus about which countries should be included in each and it is first attested in 1845 to refer to the North and South Americas, before they were regarded as separate continents. Its use to refer to the Indian subcontinent is seen from the twentieth century. It was especially convenient for referring to the region comprising both the British India and the states under British Paramountcy. The term Indian subcontinent also has a geological significance and it was, like the various continents, a part of the supercontinent of Gondwana. A series of tectonic splits caused formation of basins, each drifting in various directions. The geological region called the Greater India once included the Madagascar, Seychelles, Antartica, as a geological term, Indian subcontinent has meant that region formed from the collision of the Indian basin with Eurasia nearly 55 million years ago, towards the end of Paleocene. The Indian subcontinent has been a particularly common in the British Empire. The region, state Mittal and Thursby, has also labelled as India, Greater India. The BBC and some sources refer to the region as the Asian Subcontinent. Some academics refer to it as South Asian Subcontinent, the terms Indian subcontinent and South Asia are sometimes used interchangeably. There is no accepted definition on which countries are a part of South Asia or Indian subcontinent. In dictionary entries, the term subcontinent signifies a large, distinguishable subdivision of a continent, the region experienced high volcanic activity and plate subdivisions, creating Madagascar, Seychelles, Antartica, Austrolasia and the Indian subcontinent basin. The Indian subcontinent drifted northeastwards, colliding with the Eurasian plate nearly 55 million years ago and this geological region largely includes Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. The zone where the Eurasian and Indian subcontinent plates meet remains one of the active areas. The English term mainly continues to refer to the Indian subcontinent, physiographically, it is a peninsular region in south-central Asia delineated by the Himalayas in the north, the Hindu Kush in the west, and the Arakanese in the east
10.
Arabian Plate
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The Arabian Plate is a minor tectonic plate in the northern and eastern hemispheres. It is one of three continental plates that have been moving northward in recent geological history and colliding with the Eurasian Plate, the Arabian Plate consists mostly of the Arabian peninsula, it extends eastward at the Sinai and the Red Sea and northward to the Levant. The Arabian Plate was part of the African plate during much of the Phanerozoic Eon, the opening of the Red Sea rift led to extensive volcanic activity. There are large volcanic fields called the Older Harrats, such as Harrat Khaybar and Harrat Rahat, some activity still continues especially around Medina, and there are regular eruptions within the Red Sea. The collision between the Arabian Plate and Eurasia is pushing up the Zagros Mountains of Iran, because the Arabian Plate and Eurasian Plate collide, many cities are in danger such as those in southeastern Turkey. These dangers include earthquakes, tsunamis, and volcanoes, countries within the plate include Lebanon, Syria, Djibouti, Yemen, Oman, Qatar, Bahrain, Kuwait, Iraq, Saudi Arabia, Jordan, and the United Arab Emirates. Regions include parts of the Southern Denkalya Subregion, the Southeastern Anatolia Region, Awdal and the Khuzestan Province
11.
Chersky Range
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The Chersky Range is a chain of mountains in northeastern Siberia between the Yana River and the Indigirka River. It generally runs from northwest to southeast through the Sakha Republic, the highest peak in the range is Peak Pobeda, which is 3,003 meters tall. The range lies on the boundary between the Eurasian and North American tectonic plates, the Chersky mountains, along with the neighboring Verkhoyansk Range, have a moderate effect on the climate of Siberia. The ridges obstruct west-moving air flows, decreasing the amount of snowfall in the plains to the west. At some time between 1633 and 1642 Poznik Ivanov ascended a tributary of the lower Lena, crossed the Verkhoyansk Range to the upper Yana, the range was sighted in 1926 by Sergei Obruchev and named by the Russian Geographical Society after the Polish explorer and geographer Ivan Chersky. The precise nature of the boundary between the North American and Eurasian tectonic plates in the area of the Chersky Range is still not fully understood and is the subject of ongoing research. By the 1980s, the Chersky Range was considered mostly a zone of continental rifting where the crust was spreading apart. There is thought to be a point in the Chersky Range where the forces coming from the north change to the compressional forces noted throughout most of the range. The Chersky Range is also thought to include a triple junction where the Ulakhan Fault intersects the suture zone. Whatever the exact nature of the regional tectonics, the Chersky Range is an active zone. It connects in the north with the extension of the Laptev Sea Rift
12.
Siberia
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Siberia is an extensive geographical region, and by the broadest definition is also known as North Asia. Siberia has historically been a part of Russia since the 17th century, the territory of Siberia extends eastwards from the Ural Mountains to the watershed between the Pacific and Arctic drainage basins. It stretches southwards from the Arctic Ocean to the hills of north-central Kazakhstan and to the borders of Mongolia. With an area of 13.1 million square kilometres, Siberia accounts for 77% of Russias land area and this is equivalent to an average population density of about 3 inhabitants per square kilometre, making Siberia one of the most sparsely populated regions on Earth. If it were a country by itself, it would still be the largest country in area, the origin of the name is unknown. Some sources say that Siberia originates from the Siberian Tatar word for sleeping land, another account sees the name as the ancient tribal ethnonym of the Sirtya, a folk, which spoke a language that later evolved into the Ugric languages. This ethnic group was assimilated to the Siberian Tatar people. The modern usage of the name was recorded in the Russian language after the Empires conquest of the Siberian Khanate, a further variant claims that the region was named after the Xibe people. The Polish historian Chycliczkowski has proposed that the name derives from the word for north. He said that the neighbouring Chinese, Arabs and Mongolians would not have known Russian and he suggests that the name is a combination of two words, su and bir. The region is of significance, as it contains bodies of prehistoric animals from the Pleistocene Epoch. Specimens of Goldfuss cave lion cubs, Yuka and another woolly mammoth from Oymyakon, a rhinoceros from the Kolyma River. The Siberian Traps were formed by one of the largest known volcanic events of the last 500 million years of Earths geological history. They continued for a million years and are considered a cause of the Great Dying about 250 million years ago. At least three species of human lived in Southern Siberia around 40,000 years ago, H. sapiens, H. neanderthalensis, the last was determined in 2010, by DNA evidence, to be a new species. Siberia was inhabited by different groups of such as the Enets, the Nenets, the Huns, the Scythians. The Khan of Sibir in the vicinity of modern Tobolsk was known as a prominent figure who endorsed Kubrat as Khagan of Old Great Bulgaria in 630, the Mongols conquered a large part of this area early in the 13th century. With the breakup of the Golden Horde, the autonomous Khanate of Sibir was established in the late 15th century, turkic-speaking Yakut migrated north from the Lake Baikal region under pressure from the Mongol tribes during the 13th to 15th century
13.
Oceanic crust
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Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. The crust overlies the solidified and uppermost layer of the mantle, the crust and the solid mantle layer together constitute oceanic lithosphere. Oceanic crust is the result of erupted mantle material originating from below the plate, cooled and in most instances and this occurs mostly at mid-ocean ridges, but also at scattered hotspots, and also in rare but powerful occurrences known as flood basalt eruptions. It is primarily composed of rocks, or sima, which is rich in iron. Although a complete section of oceanic crust has not yet been drilled, Oceanic crust is significantly simpler than continental crust and generally can be divided in three layers. Layer 1 is on an average 0.4 km thick and it consists of unconsolidated or semiconsolidated sediments, usually thin or even not present near the mid-ocean ridges but thickens farther away from the ridge. Layer 3 is formed by slow cooling of magma beneath the surface and consists of coarse grained gabbros and it constitutes over two-thirds of oceanic crust volume with almost 5 km thickness. The most voluminous volcanic rocks of the floor are the mid-oceanic ridge basalts. These rocks have low concentrations of large ion lithophile elements, light rare earth elements, volatile elements, there can be found basalts enriched with incompatible elements, but they are rare and associated with mid-ocean ridge hot spots such as surroundings of Galapagos Islands, the Azores and Iceland. Oceanic crust is continuously being created at mid-ocean ridges, as plates diverge at these ridges, magma rises into the upper mantle and crust. As it moves away from the ridge, the lithosphere becomes cooler and denser, the youngest oceanic lithosphere is at the oceanic ridges, and it gets progressively older away from the ridges. As the mantle rises it cools and melts, as the pressure decreases, the amount of melt produced depends only on the temperature of the mantle as it rises. Hence most oceanic crust is the same thickness, an example of this is the Gakkel Ridge under the Arctic Ocean. Thicker than average crust is found above plumes as the mantle is hotter and hence it crosses the solidus and melts at a depth, creating more melt. An example of this is Iceland which has crust of thickness ~20 km, the oceanic lithosphere subducts at what are known as convergent boundaries. These boundaries can exist between oceanic lithosphere on one plate and oceanic lithosphere on another, or between oceanic lithosphere on one plate and continental lithosphere on another, in the second situation, the oceanic lithosphere always subducts because the continental lithosphere is less dense. The subduction process consumes older oceanic lithosphere, so oceanic crust is more than 200 million years old. The process of super-continent formation and destruction via repeated cycles of creation and destruction of oceanic crust is known as the Wilson cycle, the oldest large scale oceanic crust is in the west Pacific and north-west Atlantic - both are about up to 180-200 million years old
14.
Mid-Atlantic Ridge
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In the North Atlantic, it separates the Eurasian and North American Plates, whereas in the South Atlantic it separates the African and South American Plates. The ridge extends from a junction with the Gakkel Ridge northeast of Greenland southward to the Bouvet Triple Junction in the South Atlantic, although the Mid-Atlantic Ridge is mostly an underwater feature, portions of it have enough elevation to extend above sea level. The section of the ridge that includes the island of Iceland is also known as the Reykjanes Ridge, the ridge has an average spreading rate of about 2.5 cm per year. A ridge under the Atlantic Ocean was first inferred by Matthew Fontaine Maury in 1850, the ridge was discovered during the expedition of HMS Challenger in 1872. A team of scientists on board, led by Charles Wyville Thomson, the existence of such a ridge was confirmed by sonar in 1925 and was found to extend around the Cape of Good Hope into the Indian Ocean by the German Meteor expedition. Ewing, Heezen and Tharp discovered that the ridge is part of a 40, the ridge is central to the breakup of the hypothetical supercontinent of Pangaea that began some 180 million years ago. The Mid-Atlantic Ridge includes a deep valley that runs along the axis of the ridge along nearly its entire length. This rift marks the boundary between adjacent tectonic plates, where magma from the mantle reaches the seafloor, erupting as lava. This trench, however, is not regarded as the boundary between the North and South American Plates, nor the Eurasian and African Plates and this bulge is thought to be caused by upward convective forces in the asthenosphere pushing the oceanic crust and lithosphere. This divergent boundary first formed in the Triassic period, when a series of three-armed grabens coalesced on the supercontinent Pangaea to form the ridge, usually, only two arms of any given three-armed graben become part of a divergent plate boundary. The failed arms are called aulacogens, and the aulacogens of the Mid-Atlantic Ridge eventually became many of the river valleys seen along the Americas. The Fundy Basin on the Atlantic coast of North America between New Brunswick and Nova Scotia in Canada is evidence of the ancestral Mid-Atlantic Ridge, atlantis Massif Central Atlantic Magmatic Province Fifteen-Twenty Fracture Zone Evans, Rachel. Plumbing Depths to Reach New Heights, Marie Tharp Explains Marine Geological Maps, the Library of Congress Information Bulletin. MAR-ECO, a Census of Marine Life project on life along the Mid-Atlantic Ridge
15.
Gakkel Ridge
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The Gakkel Ridge is a mid-oceanic ridge, a divergent tectonic plate boundary between the North American Plate and the Eurasian Plate. It is located in the Eurasian Basin of the Arctic Ocean, geologically, it connects the northern end of the Mid-Atlantic Ridge with the Laptev Sea Rift. The existence and approximate location of the Gakkel Ridge were predicted by Soviet polar explorer Yakov Yakovlevich Gakkel, the Ridge is named after him, and the name was recognized in April 1987 by SCUFN. The ridge is the slowest known spreading ridge on earth, with a rate of less than one centimeter per year, until 1999, it was believed to be non-volcanic, that year, scientists operating from a nuclear submarine discovered active volcanos along it. In 2001 two research icebreakers, the German Polarstern and the American Healy, with groups of scientists, cruised to the Gakkel Ridge to explore it. Among other discoveries, this expedition found evidence of hydrothermal vents and these suggest volatile substances in concentrations ten times those in the magmas of normal mid-ocean ridges. Using free-swimming robotic submersibles on the Gakkel ridge, the AGAVE expedition also discovered what they called bizarre mats of microbial communities containing a dozen or more new species
16.
North American Plate
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The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, the Bahamas, extreme northeastern Russia, and parts of Iceland and the Azores. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia, the plate includes both continental and oceanic crust. The interior of the continental landmass includes an extensive granitic core called a craton. Along most of the edges of this craton are fragments of material called terranes. It is thought that much of North America west of the Rocky Mountains is composed of such terranes, the parallel Septentrional and Enriquillo-Plantain Garden faults, which run through the island of Hispaniola and bound the Gonâve Microplate, are also a part of the boundary. On the northerly boundary is a continuation of the Mid-Atlantic ridge called the Gakkel Ridge, the rest of the boundary in the far northwestern part of the plate extends into Siberia. On its western edge, the Farallon Plate has been subducting under the North American Plate since the Jurassic Period, the Juan de Fuca, Explorer, Gorda, Rivera, Cocos and Nazca plates are remnants of the Farallon Plate. The boundary along the Gulf of California is complex and it is generally accepted that a piece of the North American Plate was broken off and transported north as the East Pacific Rise propagated northward, creating the Gulf of California. A few hotspots are thought to exist below the North American Plate, the most notable hotspots are the Yellowstone, Raton, and Anahim hotspots. The Yellowstone and Anahim hotspots are thought to have first arrived during the Miocene period and are still geologically active, for the most part, the North American Plate moves in roughly a southwest direction away from the Mid-Atlantic Ridge. One recent study suggests that a convective current is propelling the plate. Geologic timeline of Western North America New Madrid Seismic Zone - an ancient intraplate fault zone within the North American Plate, notable as early as 1699 Notes
17.
Philippine Sea Plate
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The Philippine Sea Plate or Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of the Philippine Mobile Belt, to the north, the Philippine Sea Plate meets the Okhotsk Plate at the Nankai Trough. The Philippine Sea Plate, the Amurian Plate, and the Okhotsk Plate meet at Mount Fuji in Japan, thickened crust of the Izu-Bonin-Mariana arc colliding with Japan constitutes the Izu Collision Zone. The eastern side of the Philippine Sea Plate is a convergent boundary with the Pacific Plate subducting at the Izu-Ogasawara Trench, the east of the plate includes the Izu-Ogasawara and the Mariana Islands, forming the Izu-Bonin-Mariana Arc system. There is also a divergent boundary between the Philippine Sea Plate and the small Mariana Plate which carries the Mariana Islands, to the south, the Philippine Sea Plate is bounded by the Caroline Plate and Birds Head Plate. To the west, the Philippine Sea Plate subducts under the Philippine Mobile Belt at the Philippine Trench, to the northwest the Philippine Sea Plate meets Taiwan and the Nansei islands on the Okinawa Plate, and southern Japan on the Amurian Plate. List of earthquakes in Guam List of earthquakes in Japan List of earthquakes in the Philippines Hall, Robert, Fuller, Michael, Ali, Jason R. Anderson, the Philippine Sea Plate Magnetism and Reconstructions. High resolution map of Tectonic Plate Boundaries Map showing Seismicity of the Earth, 1900‒2012, Philippine Sea Plate and Vicinity United States Geological Survey
18.
Okhotsk Plate
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The Okhotsk Plate is a minor tectonic plate covering the Sea of Okhotsk, the Kamchatka Peninsula, Sakhalin Island and Tōhoku and Hokkaidō in Japan. It was formerly considered a part of the North American Plate, the boundary is a left-lateral moving transform fault, the Ulakhan Fault. The earthquake devastated Neftegorsk, and the town was not rebuilt after the earthquake, other notable intraplate earthquakes such as the 1983 Sea of Japan earthquake and the 1993 Hokkaidō earthquake triggered tsunamis in the Sea of Japan. The boundary between Okhotsk Plate and Pacific Plate is a zone, where Pacific Plate subducts beneath the Okhotsk Plate. Many strong megathrust earthquakes occurred here, some of them among the largest on world record, GPS measurements and other studies show that the Okhotsk Plate is slowly rotating in a clockwise direction. Models indicate that it rotates 0.2 deg/Myr about a pole located north of Sakhalin, Okhotsk Plate Modeling Joint US-Russia Workshop on the Plate Tectonic Evolution of Northeast Russia, Dec.2004
19.
Amurian Plate
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The Amurian Plate is a minor tectonic plate in the northern and eastern hemispheres. It covers Manchuria, the Korean Peninsula, Western Japan, once thought to be a part of the Eurasian Plate, the Amur Plate is now generally considered to be a separate plate moving southeast with respect to the Eurasian Plate. The Amurian Plate is named after the Amur River, that forms the border between the Russian Far East and Northeastern China, the Baikal Rift Zone is considered a boundary between the Amurian Plate and the Eurasian Plate. GPS measurements indicate that the plate is slowly rotating counterclockwise, the Amurian Plate may have been involved in the 1976 Tangshan earthquake in China. Determination of the Amurian Plate Motion, mantle Dynamics and Plate Interactions in East Asia, Geodynamics Series. V.27, edited by M. F. J. Flower et al
20.
Divergent boundary
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In plate tectonics, a divergent boundary or divergent plate boundary is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent boundaries within continents initially produce rifts which eventually become rift valleys, most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges. Divergent boundaries also form volcanic islands which occur when the plates apart to produce gaps which molten lava rises to fill. Current research indicates that complex convection within the Earths mantle allows material to rise to the base of the lithosphere beneath each divergent plate boundary. This supplies the area with vast amounts of heat and a reduction in pressure that melts rock from the asthenosphere beneath the area forming large flood basalt or lava flows. Each eruption occurs in only a part of the boundary at any one time. Over millions of years, tectonic plates may move many hundreds of kilometers away from both sides of a divergent plate boundary, because of this, rocks closest to a boundary are younger than rocks further away on the same plate. At divergent boundaries, two plates move apart from other and the space that this creates is filled with new crustal material sourced from molten magma that forms below. The origin of new divergent boundaries at triple junctions is thought to be associated with the phenomenon known as hotspots. Here, exceedingly large convective cells bring very large quantities of hot asthenospheric material near the surface, the hot spot which may have initiated the Mid-Atlantic Ridge system currently underlies Iceland which is widening at a rate of a few centimeters per year. Divergent boundaries can create massive fault zones in the ridge system. Spreading is generally not uniform, so where spreading rates of adjacent ridge blocks are different and these are the fracture zones, many bearing names, that are a major source of submarine earthquakes. A sea floor map will show a strange pattern of blocky structures that are separated by linear features perpendicular to the ridge axis. If one views the sea floor between the zones as conveyor belts carrying the ridge on each side of the rift away from the spreading center the action becomes clear. Crest depths of the old ridges, parallel to the current spreading center and it is at mid-ocean ridges that one of the key pieces of evidence forcing acceptance of the seafloor spreading hypothesis was found. Airborne geomagnetic surveys showed a pattern of symmetrical magnetic reversals on opposite sides of ridge centers. The pattern was far too regular to be coincidental as the widths of the bands were too closely matched. Scientists had been studying polar reversals and the link was made by Lawrence W. Morley, Frederick John Vine, the magnetic banding directly corresponds with the Earths polar reversals
21.
Iceland
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Iceland is a Nordic island country in the North Atlantic Ocean. It has a population of 332,529 and an area of 103,000 km2, the capital and largest city is Reykjavík. Reykjavík and the areas in the southwest of the country are home to over two-thirds of the population. Iceland is volcanically and geologically active, the interior consists of a plateau characterised by sand and lava fields, mountains and glaciers, while many glacial rivers flow to the sea through the lowlands. Iceland is warmed by the Gulf Stream and has a climate, despite a high latitude just outside the Arctic Circle. Its high latitude and marine influence still keeps summers chilly, with most of the archipelago having a tundra climate. According to the ancient manuscript Landnámabók, the settlement of Iceland began in the year 874 AD when the Norwegian chieftain Ingólfr Arnarson became the first permanent settler on the island. In the following centuries, Norwegians, and to a lesser extent other Scandinavians, emigrated to Iceland, the island was governed as an independent commonwealth under the Althing, one of the worlds oldest functioning legislative assemblies. Following a period of strife, Iceland acceded to Norwegian rule in the 13th century. The establishment of the Kalmar Union in 1397 united the kingdoms of Norway, Denmark, Iceland thus followed Norways integration to that Union and came under Danish rule after Swedens secession from that union in 1523. In the wake of the French revolution and the Napoleonic wars, Icelands struggle for independence took form and culminated in independence in 1918, until the 20th century, Iceland relied largely on subsistence fishing and agriculture, and was among the poorest in Europe. Industrialisation of the fisheries and Marshall Plan aid following World War II brought prosperity, in 1994, it became a part of the European Economic Area, which further diversified the economy into sectors such as finance, biotechnology, and manufacturing. Iceland has an economy with relatively low taxes compared to other OECD countries. It maintains a Nordic social welfare system that provides health care. Iceland ranks high in economic, political and social stability and equality, in 2013, it was ranked as the 13th most-developed country in the world by the United Nations Human Development Index. Iceland runs almost completely on renewable energy, some bankers were jailed, and the economy has made a significant recovery, in large part due to a surge in tourism. Icelandic culture is founded upon the nations Scandinavian heritage, most Icelanders are descendants of Germanic and Gaelic settlers. Icelandic, a North Germanic language, is descended from Old Norse and is related to Faroese
22.
Eldfell
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Eldfell is a composite volcanic cone just over 200 metres high on the Icelandic island of Heimaey. It formed in an eruption which began on the eastern side of Heimaey in the Westman Islands on 23 January 1973. This came without any sign of warning, the name of Eldfell means Mountain of Fire in Icelandic. The eruption caused a crisis for the island and nearly led to its permanent evacuation. Volcanic ash fell over most of the island, destroying around 400 homes, and a lava flow threatened to close off the harbour, the islands main income source via its fishing fleet. An operation was mounted to cool the lava flow by pumping sea water onto it. After the eruption, the islanders used heat from the lava flows to provide hot water. They also used some of the extensive tephra, fall-out of airborne material, to extend the runway at the islands small airport. It is estimated that a third of all the lava erupted in the world in recorded history has been produced by Icelandic eruptions. The Vestmannaeyjar archipelago lies off the south coast of Iceland, and consists of small islands. Heimaey, the largest island in the group and the only inhabited one, the most prominent feature on Heimaey before 1973 was Helgafell, a 200 meters high volcanic cone formed in an eruption about 5,000 years ago. The Vestmannaeyjar archipelago was settled in about 874 AD, originally by escaped Irish slaves belonging to Norse settlers on the mainland and these settlers gave the islands their name, Ireland being west of mainland Scandinavia. However, offshore eruptions may have taken place in 1637 and 1896, scientists have speculated that volcanic activity in the archipelago may be increasing due to the southward propagation of the rift zone that crosses Iceland. At about 20,00 on 21 January 1973, a series of tremors began to occur around Heimaey. The tremors continued at a reduced rate until 11,00 that day, from 23,00 until 01,34 on 23 January, seven tremors were detected that grew shallower and more intense, while the epicenter moved closer to the town of Vestmannaeyjar. The largest tremor measured 2.7 on the Richter scale, small tremors are very common at plate boundaries, and nothing here indicated that they heralded a major eruption. The onset of the eruption was therefore almost entirely unexpected, the fissure rapidly extended from 300 metres to a length of 2 kilometres, crossing the island from one shore to the other. Submarine activity also occurred just offshore at the northern and southern ends of the fissure. 8-kilometre north of the old volcanic cone of Helgafell, the name initially given to the new volcano was Kirkjufell, owing to its proximity to Kirkjubær
23.
Laki
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Laki or Lakagígar is a volcanic fissure in the south of Iceland, not far from the canyon of Eldgjá and the small village of Kirkjubæjarklaustur. Lakagígar is the name, as Laki mountain itself did not erupt. Lakagígar is part of a system centered on the volcano Grímsvötn. It lies between the glaciers of Mýrdalsjökull and Vatnajökull, in an area of fissures that run in a southwest to northeast direction and this led to a famine which then killed approximately 25% of the islands human population. The lava flows also destroyed 20 villages The Laki eruption and its caused a drop in global temperatures. This caused crop failures in Europe and may have caused droughts in North Africa, on 8 June 1783, a 25 km long fissure with 130 craters opened with phreatomagmatic explosions because of the groundwater interacting with the rising basalt magma. Over a few days the eruptions became less explosive, Strombolian, the eruption, also known as the Skaftáreldar or Síðueldur, produced an estimated 14 km3 of basalt lava, and the total volume of tephra emitted was 0.91 km3. Lava fountains were estimated to have reached heights of 800 to 1,400 m, the gases were carried by the convective eruption column to altitudes of about 15 km. The eruption continued until 7 February 1784, but most of the lava was ejected in the first five months, Grímsvötn volcano, from which the Laki fissure extends, was also erupting at the time, from 1783 until 1785. The consequences for Iceland, known as the Móðuharðindin Mist Hardships, were disastrous, an estimated 20–25% of the population died in the famine and fluoride poisoning after the fissure eruptions ensued. Around 80% of sheep, 50% of cattle and 50% of horses died because of dental fluorosis, the parish priest and dean of Vestur-Skaftafellssýsla, Jón Steingrímsson, grew famous because of the eldmessa that he delivered on 20 July 1783. This past week, and the two prior to it, more poison fell from the sky than words can describe, ash, volcanic hairs, rain full of sulfur and saltpeter, all of it mixed with sand. The snouts, nostrils, and feet of livestock grazing or walking on the grass turned bright yellow, all water went tepid and light blue in color and gravel slides turned gray. All the earths plants burned, withered and turned gray, one after another, the resulting famine that afflicted Egypt in 1784 cost it roughly one-sixth of its population. The eruption was also found to have affected the southern Arabian Peninsula, the summer of 1783 was the hottest on record and a rare high-pressure zone over Iceland caused the winds to blow to the south-east. The fog was so thick that boats stayed in port, unable to navigate, inhaling sulphur dioxide gas causes victims to choke as their internal soft tissue swells – the gas reacts with the moisture in lungs and produces sulfurous acid. The local death rate in Chartres was up by 5% during August and September and it has been estimated that 23,000 British people died from the poisoning. The weather became very hot, causing severe thunderstorms with large hailstones that were reported to have killed cattle, the winter of 1783–1784 was very severe, the naturalist Gilbert White in Selborne, Hampshire, reported 28 days of continuous frost
24.
Indian Plate
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The Indian Plate or India Plate is a major tectonic plate straddling the equator in the eastern hemisphere. Originally a part of the ancient continent of Gondwana, India broke away from the fragments of Gondwana 100 million years ago. The Indian plate includes most of South Asia—i. e, until roughly 140 million years ago, the Indian Plate formed part of the supercontinent Gondwana together with modern Africa, Australia, Antarctica, and South America. Gondwana broke up as these continents drifted apart at different velocities, in the late Cretaceous, approximately 100 million years ago and subsequent to the splitting off from Gondwana of conjoined Madagascar and India, the Indian Plate split from Madagascar. It began moving north, at about 20 centimetres per year, however, some authors suggest that the collision between India and Eurasia occurred much later, around 35 million years ago. If the collision occurred between 55 and 50 Mya, the Indian Plate would have covered a distance of 3,000 to 2,000 kilometres, moving faster than any other known plate. These authors propose a continental fragment of northern Gondwana rifted from India, traveled northward and this was followed by the hard collision between India and Asia occurred at ~25 Ma. In 2007, German geologists suggested that the reason the Indian Plate moved so quickly is that it is half as thick as the other plates which formerly constituted Gondwana. The mantle plume that once broke up Gondwana might also have melted the part of the Indian subcontinent. The remains of this plume today form the Marion Hotspot, the Kerguelen hotspot, as India moved north, it is possible that the thickness of the Indian plate degenerated further as it passed over the hotspots and magmatic extrusions associated with the Deccan and Rajmahal Traps. The Indian Plate is currently moving north-east at 5 centimetres per year and this is causing the Eurasian Plate to deform, and the Indian Plate to compress at a rate of 4 millimetres per year. The westerly side of the Indian Plate is a boundary with the Arabian Plate called the Owen Fracture Zone. The northerly side of the Plate is a convergent boundary with the Eurasian Plate forming the Himalaya, List of tectonic plates List of tectonic plate interactions Paleogeography
25.
Sunda Plate
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The Sunda Plate is a minor tectonic plate straddling the equator in the eastern hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, the Indo-Australian Plate dips beneath the Sunda Plate along the Sunda Trench, which generates frequent earthquakes. The eastern, southern, and western boundaries of the Sunda Plate are tectonically complex, only the northern boundary is relatively quiescent. Kutai basin List of earthquakes in Indonesia Sunda Arc Sunda Shelf Sunda Trench Bird, an updated digital model of plate boundaries, Geochemistry Geophysics Geosystems,4,1027, doi,10. 1029/2001GC000252. Also available as a PDF file
26.
Pacific Plate
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The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate, the Pacific Plate contains an interior hot spot forming the Hawaiian Islands. Hillis and Müller are reported to consider the Birds Head Plate to be moving in unison with the Pacific Plate, bird considers them to be unconnected. The north-eastern side is a divergent boundary with the Explorer Plate, the Juan de Fuca Plate and the Gorda Plate forming respectively the Explorer Ridge, the Juan de Fuca Ridge and the Gorda Ridge. In the middle of the side is a transform boundary with the North American Plate along the San Andreas Fault. The south-eastern side is a divergent boundary with the Nazca Plate forming the East Pacific Rise, the southern side is a divergent boundary with the Antarctic Plate forming the Pacific-Antarctic Ridge. The Alpine Fault marks a boundary between the two plates, and further south the Indo-Australian Plate subducts under the Pacific Plate forming the Puysegur Trench. The southern part of Zealandia, which is to the east of this boundary, is the plates largest block of continental crust, the northern side is a convergent boundary subducting under the North American Plate forming the Aleutian Trench and the corresponding Aleutian Islands. The Pacific Plate is almost entirely oceanic crust, but it contains some continental crust in New Zealand, Baja California, the Pacific Plate has the distinction of showing one of the largest areal sections of the oldest members of seabed geology being entrenched into eastern Asian oceanic trenches. The oldest member disappearing by way of the Plate Tectonics cycle is early-Cretaceous, all maps of the Earths ocean floor geology show ages younger than 145 million years, only about 1/30 of the Earths 4.55 billion year history
27.
South American Plate
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The South American Plate is a tectonic plate which includes the continent of South America and also a sizeable region of the Atlantic Ocean seabed extending eastward to the Mid-Atlantic Ridge. The easterly side is a divergent boundary with the African Plate forming the part of the Mid-Atlantic Ridge. The southerly side is a boundary with the Antarctic Plate. The westerly side is a convergent boundary with the subducting Nazca Plate, the northerly side is a boundary with the Caribbean Plate and the oceanic crust of the North American Plate. At the Chile Triple Junction in Taitato-Tres Montes Peninsula, an oceanic ridge — the Chile Rise — is subducting under the South American plate, the South American Plate is in motion. Parts of the plate boundaries consisting of alternations of relatively short transform fault, moving westward away from the Mid-Atlantic Ridge. The eastward-moving and more dense Nazca Plate is subducting under the edge of the South American Plate along the Pacific coast of the continent at a rate of 77 mm per year. This collision of plates is responsible for lifting the massive Andes Mountains and causing the volcanoes which are strewn throughout them
28.
Caribbean Plate
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The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the north coast of South America. Roughly 3.2 million square kilometers in area, the Caribbean Plate borders the North American Plate, the South American Plate, the Nazca Plate and these borders are regions of intense seismic activity, including frequent earthquakes, occasional tsunamis, and volcanic eruptions. Part of the Puerto Rico Trench, the deepest part of the Atlantic Ocean, the Puerto Rico trench is at a complex transition from the subduction boundary to the south and the transform boundary to the west. The eastern boundary is a zone, the Lesser Antilles subduction zone. Subduction forms the islands of the Lesser Antilles Volcanic Arc from the Virgin Islands in the north to the islands off the coast of Venezuela in the south. Large historical earthquakes in 1839 and 1843 in this region are possibly megathrust earthquakes and this boundary is in part the result of transform faulting along with thrust faulting and some subduction. The rich Venezuelan petroleum fields possibly result from this complex plate interaction, the Caribbean plate is moving eastward about 22 millimeters per year in relation to the South American plate. In Venezuela much of the movement between the Caribbean Plate and the South American plate occurs along the faults of Boconó, El Pilar, the western portion of the plate is occupied by Central America. The Cocos Plate in the Pacific Ocean is subducted beneath the Caribbean Plate and this subduction forms the volcanoes of Guatemala, El Salvador, Nicaragua, and Costa Rica, also known as the Central America Volcanic Arc. The usual theory as to the origin of the Caribbean Plate was confronted by a theory in 2002. The mainstream theory holds that it is the Caribbean large igneous province formed in the Pacific Ocean tens of millions of years ago. As the Atlantic Ocean widened, North America and South America were pushed westward, the Pacific Ocean floor subducted under this oceanic crust between the continents. With the formation of the Isthmus of Panama 3 million years ago, the more recent theory asserts that the Caribbean Plate came into being from an Atlantic hotspot which no longer exists. The Caribbean Plate began its eastward migration 80 million years ago during the Late Cretaceous and this migration eventually resulted in a volcanic arc stretching from north-western South America to the Yucatán Peninsula, today represented by the Aves Islands and the Lesser and Greater Antilles
29.
Caroline Plate
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The Caroline Plate is a minor tectonic plate that straddles the Equator in the eastern hemisphere located north of New Guinea. It forms a zone along the border with the Birds Head Plate. A transform boundary forms the border with the Pacific Plate. Along the border with the Philippine Sea Plate is a convergent boundary that transitions into a rift, the Caroline Plate was first proposed as a distinct plate by Weissel & Anderson 1978. A separate terrane with its own history, the Caroline Plate has been considered part of the Pacific Plate because of sparse seismicity. It includes the West and East Caroline basins and the inactive Eauripik Rise separating them and it is subducting under the Birds Head and Woodlark plates along the New Guinea Trench to the south. The boundary with the Philippine Sea to the west has two segments, the segment, the Ayu Trough was spreading at a rate of 8 mm/yr c. 25–2 Ma but has been slowing down since, the northern segment, the Palau and southern Yap trenches, is not an active subduction zone as indicated by the lack of active volcanoes. The Caroline-Pacific boundary is a complex, evolving system partly and potentially developing into a subduction zone, the south-east boundary, along the Manus Trench, is a convergent boundary, but in the absence of active volcanoes and earthquakes, is not a subduction zone at present. The Caroline Plate moves at velocities close to those of the Pacific Plate and its age of formation. There is a slow rate of spreading between the Caroline and Philippine plates but the Caroline Plate apparently moved together with both the Philippine and New Guinea plates during the Neogene. The Caroline Plate was, under all circumstances, a plate in the past. The boundary along its side, the Mussau Trench, must have been an important boundary since magnetic anomalies on the Caroline Plate are Oligocene. There are indications of spreading in the Caroline Sea 34–27 Ma, if the Caroline Plate moved with the Pacific Plate there should be clear evidences of a corresponding subduction beneath New Guinea, of which there is virtually none. The Auy Trough is a spreading zone that opened 15 Ma
30.
Cocos Plate
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The Cocos Plate is an oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it. The Cocos Plate was created by sea floor spreading along the East Pacific Rise, from the rise the plate is pushed eastward and pushed or dragged under the less dense overriding Caribbean Plate, in the process called subduction. The subducted leading edge heats up and adds its water to the mantle above it, in the mantle layer called the asthenosphere, mantle rock melts to make magma, trapping superheated water under great pressure. The northern boundary of the Cocos Plate is the Middle America Trench, the eastern boundary is a transform fault, the Panama Fracture Zone. The southern boundary is a ridge, the Galapagos Rise. The western boundary is another ridge, the East Pacific Rise. The Cocos and Nazca Plates are the remnants of the former Farallon Plate, a hotspot under the Galapagos Islands lies along the Galapagos Rise. The Rivera Plate north of the Cocos Plate is thought to have separated from the Cocos Plate 5-10 million years ago, the boundary between the two plates appears to lack a definite transform fault, yet they are regarded as distinct. The devastating 1985 Mexico City earthquake was a result of the subduction of the Cocos Plate beneath the North American Plate, the also devastating 2001 El Salvador earthquakes were generated in the subduction of this plate on the Caribbean Plate. The volcanic arc Martin Meschede and Udo Barckhausen, Plate tectonic evolution of the Cocos-Nazca plate, reconstructing its geological evolution
31.
Juan de Fuca Plate
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It is named after the explorer of the same name. One of the smallest of Earths tectonic plates, the Juan de Fuca Plate is a remnant part of the once-vast Farallon Plate, the Juan de Fuca plate system has its origins with Panthalassas oceanic basin and crust. This oceanic crust has primarily been subducted under the North American plate, Panthalassas oceanic plate remnants are understood to be the Juan de Fuca, Gorda, Cocos and the Nazca plates, all four of which were part of the Farallon Plate. The Juan de Fuca plate is bounded on the south by the Blanco Fracture Zone, on the north by the Nootka Fault and along the west by the Pacific Plate. The Juan de Fuca plate itself has since fractured into three pieces, and the name is applied to the plate in some references. The three fragments are differentiated as such, the piece to the south is known as the Gorda Plate, the separate pieces are demarcated by the large offsets of the undersea spreading zone. These in turn are part of the Pacific Ring of Fire, the last megathrust earthquake at the Cascadia subduction zone was the 1700 Cascadia earthquake, estimated to have a moment magnitude of 8.7 to 9.2. Based on carbon dating of tsunami deposits, it occurred around 1700. As reported in National Geographic on 8 December 2003, Japanese records indicate the quake caused a tsunami in Japan, in 2008, small earthquakes were observed within the plate. The unusual quakes were described as more than 600 quakes over the past 10 days in a basin 150 miles southwest of Newport. The quakes were unlike most quakes in that they did not follow the pattern of a quake, followed by smaller aftershocks, rather. Furthermore, they did not occur on the plate boundary. The subterranean quakes were heard on hydrophones, and scientists described the sounds as similar to thunder, the basaltic formations of this plate could potentially be suitable for long-term CO2 sequestration as part of a carbon capture and storage system. Injection of CO2 would lead to the formation of stable carbonates and it is estimated that 100 years of US carbon emissions could be stored securely, without risk of leakage back into the atmosphere. Geology of the Pacific Northwest Plate tectonics National Geographic on Japanese records verifying an American earthquake Cascadia tectonic history with map
32.
Nazca Plate
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The Nazca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru–Chile Trench, of the Nazca Plate under the South American Plate is largely responsible for the Andean orogeny. The Nazca Plate is bounded on the west by the Pacific Plate and to the south by the Antarctic Plate through the East Pacific Rise and the Chile Rise respectively. The movement of the Nazca Plate over several hotspots has created some volcanic islands as well as east-west running seamount chains that subduct under South America, the oldest rocks of the plate are about 50 million years old. A triple junction, the Chile Triple Junction, occurs on the seafloor of the Pacific Ocean off Taitao, here three tectonic plates meet, the Nazca Plate, the South American Plate, and the Antarctic Plate. The eastern margin is a convergent boundary subduction zone under the South American Plate, the southern side is a divergent boundary with the Antarctic Plate, the Chile Rise, where seafloor spreading permits magma to rise. The western side is a divergent boundary with the Pacific Plate, the northern side is a divergent boundary with the Cocos Plate, the Galapagos Rise. The subduction of the Nazca plate under southern Chile has a history of producing massive earthquakes, including the largest ever recorded on earth, the moment magnitude 9.51960 Valdivia earthquake. A second triple junction occurs at the northwest corner of the plate where the Nazca, Cocos, yet another triple junction occurs at the southwest corner at the intersection of the Nazca, Pacific, and Antarctic Plates off the coast of southern Chile. At each of these triple junctions an anomalous microplate exists, the Galapagos Microplate at the northern junction, the Easter Island Microplate is a third microplate that is located just north of the Juan Fernandez Microplate and lies just west of Easter Island. The Carnegie Ridge is a 1, 350-km-long and up to 300-km-wide feature on the floor of the northern Nazca Plate that includes the Galápagos archipelago at its western end. It is being subducted under South America with the rest of the Nazca Plate, Darwin Gap is the area between the Nazca Plate and the coast of Chile, where Charles Darwin experienced the earthquake of 1835. It is expected that this area will be the epicenter of a quake in the near future. The absolute motion of the Nazca Plate has been calibrated at 3.7 cm/yr east motion, the subducting Nazca Plate, which exhibits unusual flat-slab subduction, is tearing as well as deforming as it is subducted. The subduction has formed, and continues to form, the volcanic Andes Mountain Range, deformation of the Nazca Plate even affects the geography of Bolivia, far to the east. Aside from the Juan Fernández Islands, this area has few other islands that are affected by the earthquakes that are a result of complicated movements at these junctions. The precursor of both the Nazca Plate and the Cocos Plate was the Farallon Plate, which split in late Oligocene, about 22.8 Mya, a date arrived at by interpreting magnetic anomalies. Subduction under the South American continent began about 140 Mya, although the formation of the parts of the Central Andes
33.
Scotia Plate
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The Scotia Plate is a tectonic plate on the edge of the South Atlantic and Southern Ocean. Roughly rhomboid, extending between 50°S 70°W and 63°S 20°W, the plate is 800 km wide and 3,000 km long. It is moving WSW at 2.2 cm /year and the South Sandwich Plate is moving east at 5.5 cm /year in a reference frame. It takes it name from the steam yacht Scotia of the Scottish National Antarctic Expedition, the Scotia Plate is made of oceanic crust and continental fragments now distributed around the Scotia Sea. Before the formation of the plate began 40 million years ago, at present the plate is almost completely submerged, with only the small exceptions of the South Georgia Islands on its north-eastern edge and the southern tip of South America. The northern edge of the Scotia plate is bounded by the South American plate, the North Scotia ridge is a left-lateral transform boundary with a transform rate of roughly 7.1 mm/yr. The Magallanes–Fagnano Fault is passing through Tierra del Fuego, North of the ridge is the 3 km deep Falkland Trough. Experts in plate tectonics have been unable to determine whether the South Georgian Islands are part of the Scotia plate or have recently accreted to the South American plate. Surface expressions of the boundary are found north of the islands suggesting a long-term presence of the transform fault there. Yet seismic studies have identified strain and thrusting south of the islands indicating the shift of the transform fault to an area south of the island. The South Georgia microcontinent was originally connected to the Roca Verdes back-arc basin until the Eocene, during the Oligocene South Georgia was reburied again as seafloor spreading took place in the West Scotia Sea. 10 Ma, finally, the South Georgia microcontinent was uplifted as a result of the collision with the Northeast Georgia Rise, the relative motion between the Scotia plate and the Antarctic plate on the western boundary is 7. 5-8.7 mm/yr. Though the South Scotia Ridge is overall a transform fault, small sections of the ridge are spreading to make up for the jagged shape of the boundary. At the eastern tip of the Antarctic Peninsula, the beginning of South Scotia Ridge, a small basin, Powel Basin, separates this cluster from the South Orkney microcontinent composed of Triassic and younger rocks. The eastern continuation of the ridge, the Scotia Arc east of the South Sandwich Plate, are the South Sandwich island arc and this volcanic active island arc has submerged ancestors in Jane and Discovery banks in the southern ridge. The western edge of the plate is bounded by the Antarctic plate, forming the Shackleton Fracture Zone, the Southern Chile Trench is a southern extension of the subduction of the Antarctic and Nazca plates below South America. Heading south along the ridge, the rate decreases until its remaining oblique motion evolves into the Shackleton Fracture Zone transform boundary. The south-western edge of the plate is bounded by the Shetland microplate separating the Shackleton Fracture Zone, North of South Shetland Islands and along the southern half of the Shackleton Fracture Zone is the remnant of the Phoenix Plate
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Somali Plate
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The Somali Plate, or Somalian Plate, is a minor tectonic plate, which straddles the equator in the eastern hemisphere. The Somali Plate formed between 60 million years ago and 10 million years ago by the rifting of the African Plate along the East African Rift. Because the East Africa Rift separates the continent into two plates, the African Plate west of the rift is sometimes referred to as the Nubian Plate, the northern boundary is the Aden Ridge along the coast of Saudi Arabia. The eastern boundary is the Central Indian Ridge, the portion of which is also known as the Carlsberg Ridge. The southern boundary is the Southwest Indian Ridge, dating of volcanism in the Comoro Islands and northern Madagascar volcanoes indicates a rate of motion to the east over a hotspot of approximately 45 mm/yr. Emerick, C. M.1985, Age progressive volcanism in the Comores Archipelago and Northern Madagascar, corvallis, PhD Thesis, Abstract Chorowicz, Jean
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Yangtze Plate
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The Yangtze Plate, also called the South China Block or the South China Subplate, comprises the bulk of southern China. The Longmenshan Fault on the border was the site of the 2008 Wenchuan earthquake. The Yangtze Plate was formed by the disaggregation of the Rodinia Supercontinent 750 million years ago, South China rifted away from the Gondwana supercontinent in the Silurian. During the formation of the great supercontinent Pangaea, South China was a smaller, separate continent located off the east coast of the supercontinent, in the Triassic the Yangtze Plate collided with the North China Plate, thereby connecting with Pangaea, and formed the Sichuan basin. In the Cenozoic the Yangtze Plate was influenced by the collision of the Indian and Eurasian plates creating the uplifting of the Longmen Mountains and its southward motion is accommodated along the Red River fault
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Adriatic Plate
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The Adriatic or Apulian Plate is a small tectonic plate carrying primarily continental crust that broke away from the African plate along a large transform fault in the Cretaceous period. The name Adriatic Plate is usually used when referring to the part of the plate. This part of the plate was deformed during the Alpine orogeny, the Adriatic/Apulian Plate is thought to still move independently of the Eurasian Plate in NNE direction with a small component of counter-clockwise rotation. The fault zone that separates the two is the Periadriatic Seam that runs through the Alps, studies indicate that in addition to deforming, the Eurasian continental crust has actually subducted to some extent below the Adriatic/Apulian Plate, an unusual circumstance in plate tectonics. This subduction is responsible for the volcanics of southern Italy. The eastern Italian Peninsula, the part of Slovenia and the Adriatic Sea are on the Adriatic/Apulian Plate. Mesozoic sedimentary rocks deposited on the plate include the limestones that form the Southern Calcareous Alps
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Aegean Sea Plate
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The Aegean Sea Plate is a small tectonic plate located in the eastern Mediterranean Sea under southern Greece and far western Turkey. Its southern edge is a subduction zone south of Crete, where the African Plate is being swept under the Aegean Sea Plate, to the north is the Eurasian Plate, which is a divergent boundary responsible for the formation of the Gulf of Corinth. An updated digital model of plate boundaries
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Anatolian Plate
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The Anatolian Plate or the Turkish Plate is a continental tectonic plate comprising most of the Anatolia peninsula. To the east, the East Anatolian Fault, a left lateral transform fault, to the south and southwest is a convergent boundary with the African Plate. The northern edge is a boundary with the Eurasian Plate. Research indicates that the Anatolian Plate is rotating counterclockwise as it is being pushed west by the Arabian Plate, in some references, the Anatolian Plate is referred to as a block of continental crust still coupled to the Eurasian Plate. But studies of the North Anatolian Fault indicate that Anatolia is de-coupled from the Eurasian Plate and it is now being squeezed by the Arabian Plate from the east and forced toward the west as the Eurasian Plate to its north is blocking motion in that direction. The African Plate is subducting beneath the Anatolian Plate along the Cyprus and Hellenic Arcs offshore in the Mediterranean Sea
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Australian Plate
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The Australian Plate is a major tectonic plate in the eastern and, largely, in the southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately 100 million years ago when India broke away and began moving north. However, recent studies suggest that the two plates have once again split apart and have separate plates for at least 3 million years. The Australian plate includes the continent of Australia, including Tasmania, as portions of New Guinea, New Zealand. The northeasterly side is a complex but generally convergent boundary with the Pacific Plate, the Pacific Plate is subducting under the Australian Plate, which forms the Tonga and Kermadec Trenches, and the parallel Tonga and Kermadec island arcs. It has also uplifted the eastern parts of New Zealands North Island, extending southwest of this trench is the Macquarie Ridge. The southerly side is a divergent boundary with the Antarctic Plate called the Southeast Indian Ridge, the subducting boundary through Indonesia is not parallel to the biogeographical Wallace line that separates the indigenous fauna of Asia from that of Australasia. The eastern islands of Indonesia lie mainly on the Eurasian Plate, but have Australasian-related fauna and flora
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Balmoral Reef Plate
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The Balmoral Reef Plate is a small tectonic plate located in the south Pacific north of Fiji. Clockwise from the north, it borders the Pacific Plate, Australian Plate, Conway Reef Plate, the northern and western borders are a divergent boundary while the rest of the borders are transform and convergent boundaries. The Balmoral Reef Plates ocean crust is less than 12 million years old and is spreading between the New Hebrides and Tonga subduction, an updated digital model of plate boundaries, Geochemistry Geophysics Geosystems,4,1027, doi,10. 1029/2001GC000252. Kagan, and D. D. Jackson, Plate tectonics and earthquake potential of spreading ridges and oceanic transform faults, in Plate Boundary Zones, Geophys. 30, edited by S. Stein and J. T. Freymueller, 203–218, AGU, Washington, D. C.2002
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Banda Sea Plate
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The Banda Sea Plate is a minor tectonic plate underlying the Banda Sea in southeast Asia. This plate also carries a portion of Sulawesi Island, the entire Seram Island, clockwise from the east it is bounded by the Birds Head Plate of western New Guinea, Australian Plate, Timor Plate, Sunda Plate, and the Molucca Sea Collision Zone. A small rift is located in the middle of Sulawesi, list of earthquakes in Indonesia Bird, P. An updated digital model of plate boundaries
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Bird's Head Plate
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The Birds Head Plate is a minor tectonic plate incorporating the Birds Head Peninsula at the western end of the island of New Guinea. Hillis & Müller consider it to be moving in unison with the Pacific Plate, bird considers it to be unconnected to the Pacific Plate. The plate is separating from the Australian Plate and the small Maoke Plate along a divergent boundary to the southeast, convergent boundaries exist along the north between the Birds Head and the Caroline Plate, the Philippine Sea Plate, and the Halmahera Plate to the northwest. A transform boundary exists between the Birds Head and the Molucca Sea Collision Zone to the southwest, another convergent boundary exists between the Birds Head and the Banda Sea Plate to the south
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Burma Plate
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The Burma Plate is a minor tectonic plate or microplate located in Southeast Asia, sometimes considered a part of the larger Eurasian Plate. The Andaman Islands, Nicobar Islands, and northwestern Sumatra are located on the plate and this island arc separates the Andaman Sea from the main Indian Ocean to the west. To its east lies the Sunda Plate, from which it is separated along a transform boundary, to the west is the much larger India Plate, which is subducting beneath the eastern facet of the Burma Plate. This extensive subduction zone has formed the Sunda Trench, as the India Plate drifted northwards at a relatively rapid rate of an average 16 cm/yr, it also rotated in an counterclockwise direction. As a result of movement and rotation, the convergence along the plates eastern boundary with Eurasia was at an oblique angle. On December 26,2004, a portion of the boundary between the Burma Plate and the Indian Plate slipped, causing the 2004 Indian Ocean earthquake. This megathrust earthquake had a moment magnitude of 9. 1–9.3 Mw. Over 1600 km of the boundary underwent thrust faulting and shifted up to 5 meters vertically and 11 meters horizontally and this rapid rise in the sea floor over such a short time generated a massive tsunami that killed approximately 229,800 people along the coast of the Indian Ocean. Curray, JR.2002 Chapman Conference on Continent – Ocean Interactions within the East Asian Marginal Seas, tectonics and History of the Andaman Sea Region. Pdf Paul, J. Burgmann, R. Gaur, V. K. Bilham, R. Larson, K. M. Ananda, M. B. Jade, S. Mukal, M. Anupama, T. S. Satyal, G. Kumar, D.2001 The motion and active deformation of India
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Easter Plate
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The Easter Plate is a small tectonic plate or microplate in the southeastern Pacific. The plate is bounded on the west by the Pacific Plate, the entire plate is covered by the Pacific Ocean. Easter Plate is named after Easter Island which is to the east of it on the adjacent Nazca Plate, an updated digital model of plate boundaries, Geochem
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Explorer Plate
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The Explorer Plate is an oceanic tectonic plate beneath the Pacific Ocean off the west coast of Vancouver Island, Canada. The eastern boundary of the Explorer Plate is being subducted under the North American Plate. The southern boundary is a collection of transform faults, the Sovanco Fracture Zone, to the southeast is another transform boundary, the Nootka Fault separating it from the Juan de Fuca Plate. To the northwest is a divergent boundary with the Pacific Plate forming the Explorer Ridge, the Explorer Plate is the northernmost remnant of the Farallon Plate. Geology of the Pacific Northwest Cascadia tectonic history
