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Cape Verde Hotspot
Cape Verde is a volcanic archipelago situated above an oceanic rise that puts the base of the islands above the rest of the seafloor. Cape Verde has been identified as a hotspot and the majority of geoscientists have argued that the archipelago is underlain by a mantle plume and that this plume is responsible for the volcanic activity and associated geothermal anomalies. Evidence for a plume origin includes substantial uplift, low-velocity seismic anomalies in the upper mantle extending to depths of around 500 km, low-velocity anomalies in the lower mantle which appear to pond beneath the transition zone with branches extending to the Azores, Canary and Cape Verde hotspots, and petrological, geochemical, and isotopic evidence which are thought to indicate a deep-mantle source. Some observations, such as a lack of age-progressive volcanism and the geochemical signatures of lavas which indicate a shallow source materials, are inconsistent with the plume model, and some scient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calhau
Ribeira de Calhau is a settlement in the eastern part of the island of São Vicente, Cape Verde, Sao Vicente, Cape Verde. It takes its name from the river Ribeira do Calhau, and comprises the villages of Madeiral, Ribeira de Calhau and Calhau. Madeiral and Ribeira de Calhau are located in the river valley, Calhau is on the east coast. In 2010 its population was 1,177. The valley is surrounded by the mountains Viana, Cape Verde, Viana, Madeiral, Pico do Vento and Monte Verde, Cape Verde, Monte Verde. The Cape Verde Atmospheric Observatory "Humberto Duarte Fonseca" is situated 1 km north of Calhau. It is part of a German-UK initiative to undertake long-term ground- and ocean-based observations in the tropical Eastern North Atlantic Ocean region. Climate Calhau has a hot desert climate like most of the island. The average annual temperature is 22.6 °C. Average rainfall is 129 millimeters. Notable person *Vasco Martins, singer and composer References {{São Vicente Villag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
African Plate
The African Plate is a major tectonic plate that includes much of the continent of Africa (except for its easternmost part) and the adjacent oceanic crust to the west and south. It is bounded by the North American Plate and South American Plate to the west (separated by the Mid-Atlantic Ridge); the Arabian Plate and Somali Plate to the east; the Eurasian Plate, Aegean Sea Plate and Anatolian Plate to the north; and the Antarctic Plate to the south. Between and , the Somali Plate began rifting from the African Plate along the East African Rift. Since the continent of Africa consists of crust from both the African and the Somali plates, some literature refers to the African Plate as the Nubian Plate to distinguish it from the continent as a whole. Boundaries The western edge of the African Plate is a divergent boundary with the North American Plate to the north and the South American Plate to the south which forms the central and southern part of the Mid-Atlantic Ridge. The A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldera
A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is gone. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a Volcanic crater, crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur each century, the formation of a caldera is a rare event, occurring only a few times per century. Only seven caldera-forming collapses are known to have occurred between 1911 and 2016. More recently, a caldera collapse occurred at Kīlauea, Hawaii in 2018. Etymology The term ''caldera'' comes from Spanish language, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe and Asia from the "New World" of the Americas in the European perception of the World. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and North and South America to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Atlantic Ocean is divided in two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) Atlantic Ocean split at about 8°N. Scientific explorations of the Atlanti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrographic Province
A petrographic province is a geological region within which the igneous rocks reveal a relationship (so-called consanguinity) in chemical composition, which may be referred to a community of origin. This relationship may be chemically a close one, but the rocks have widely varying mineralogical composition, or the kinship may be restricted to one or more of the chemical components in the rocks. Etymology Petrography Petrography is a branch of petrology that focuses on detailed descriptions of rocks. Someone who studies petrography is called a petrographer. The mineral content and the textural relationships within the rock are described in detail. The classi ... derives from ( el, πέτρα), meaning 'rock', and ( el, γράφειν), 'to write'. References * {{Cite NIE, wstitle=Petrographic Province, short=x, vb=x Petrology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pluton
In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and compositions, illustrated by examples like the Palisades Sill of New York and New Jersey; the Henry Mountains of Utah; the Bushveld Igneous Complex of South Africa; Shiprock in New Mexico; the Ardnamurchan intrusion in Scotland; and the Sierra Nevada Batholith of California. Because the solid country rock into which magma intrudes is an excellent insulator, cooling of the magma is extremely slow, and intrusive igneous rock is coarse-grained (phaneritic). Intrusive igneous rocks are classified separately from extrusive igneous rocks, generally on the basis of their mineral content. The relative amounts of quartz, alkali feldspar, plagioclase, and feldspathoid is particularly important in classifying intrusive igneous rocks. Intrusions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust. Geological significance Igneous and metamorphic rocks make up 90–95% of the top ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Pan (geology)
Natural salt pans or salt flats are flat expanses of ground covered with salt and other minerals, usually shining white under the sun. They are found in deserts and are natural formations (unlike salt evaporation ponds, which are artificial). A salt pan forms by evaporation of a water pool, such as a lake or pond. This happens in climates where the rate of water evaporation exceeds the rate of that is, in a desert. If the water cannot drain into the ground, it remains on the surface until it evaporates, leaving behind minerals precipitated from the salt ions dissolved in the water. Over thousands of years, the minerals (usually salts) accumulate on the surface. These minerals reflect the sun's rays (through radiation) and often appear as white areas. Salt pans can be dangerous. The crust of salt can conceal a quagmire of mud that can engulf a truck. The Qattara Depression in the eastern Sahara Desert contains many such traps which served as strategic barriers during World ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Domain
The public domain (PD) consists of all the creative work A creative work is a manifestation of creative effort including fine artwork (sculpture, paintings, drawing, sketching, performance art), dance, writing (literature), filmmaking, and composition. Legal definitions Creative works require a cre ... to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired, anyone can legally use or reference those works without permission. As examples, the works of William Shakespeare, Ludwig van Beethoven, Leonardo da Vinci and Georges Méliès are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired. Some works are not covered by a country's copyright laws, and are therefore in the public domain; for example, in the United States, items excluded from copyright include the for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peace Corps
The Peace Corps is an independent agency and program of the United States government that trains and deploys volunteers to provide international development assistance. It was established in March 1961 by an executive order of President John F. Kennedy Executive Order 10924 and authorized by Congress the following September by the Peace Corps Act. Kennedy first publicly proposed the Peace Corps during his 1960 presidential campaign as a means to improve America's global image and leadership in the Cold War; he cited the Soviet Union's deployment of skilled citizens "abroad in the service of world communism" and argued the U.S. must do the same to advance values such as democracy and liberty. The Peace Corps was formally established within three months of Kennedy's presidency, garnering both bipartisan congressional support and popular support, particularly among recent university graduates. The official goal of the Peace Corps is to assist developing countries by providing skil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
