1.
Marquesas Keys
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The Marquesas Keys form an uninhabited island group about 20 miles west of Key West,4 miles in diameter, and largely covered by mangrove forest. They are an area of Monroe County, Florida and belong to the Lower Keys Census County Division. They are protected as part of the Key West National Wildlife Refuge, the Marquesas were used for target practice by the military as recently as 1980. The total area, including the lagoon, measures 29.37 km2, the group is located at coordinates 24°34′19″N 82°07′10″W. Only the Dry Tortugas are farther west,36 miles west of the Marquesas Keys, the central lagoon is called Mooney Harbor. The northernmost key is the largest and has a strip of sandy beach free of mangrove, in the past it was known as Entrance Key. It surrounds the lagoon in the north and east, adjoining in the south are smaller keys such as Gull Keys, Mooney Harbor Key, and finally about four unnamed keys in the southwest corner of the group. Older charts show that two of these once were named Button Island and Round Island. Six miles west of the Marquesas Keys is Rebecca Shoal, the islands are best known for their excellent sport fishing
2.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
3.
Polynesia
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Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including the language family, culture, and beliefs. Historically, they were experienced sailors who used stars to navigate at night, the term Polynesia was first used in 1756 by French writer Charles de Brosses, and originally applied to all the islands of the Pacific. In 1831, Jules Dumont dUrville proposed a restriction on its use during a lecture to the Geographical Society of Paris, historically, these islands have also been referred to as the South Sea Islands. Polynesia is characterized by an amount of land spread over a very large portion of the mid. Most Polynesian islands and archipelagos, including the Hawaiian Islands and Samoa, are composed of volcanic islands built by hotspots, New Zealand, Norfolk Island, and Ouvéa, the Polynesian outlier near New Caledonia, are the unsubmerged portions of the largely sunken continent of Zealandia. At first, the Pacific plate was subducted under the Australian plate, the Alpine Fault that traverses the South Island is currently a transform fault while the convergent plate boundary from the North Island northwards is called the Kermadec-Tonga Subduction Zone. The volcanism associated with subduction zone is the origin of the Kermadec. Out of approximately 300,000 or 310,000 square kilometres of land, over 270,000 km2 are within New Zealand, the Zealandia continent has approximately 3,600,000 km2 of continental shelf. The oldest rocks in the region are found in New Zealand and are believed to be about 510 million years old, the oldest Polynesian rocks outside of Zealandia are to be found in the Hawaiian Emperor Seamount Chain, and are 80 million years old. Polynesia is generally defined as the islands within the Polynesian Triangle, geographically, the Polynesian Triangle is drawn by connecting the points of Hawaii, New Zealand and Easter Island. The other main island groups located within the Polynesian Triangle are Samoa, Tonga, there are also small Polynesian settlements in Papua New Guinea, the Solomon Islands, the Caroline Islands, and in Vanuatu. An island group with strong Polynesian cultural traits outside of this triangle is Rotuma. The people of Rotuma have many common Polynesian traits but speak a non-Polynesian language, some of the Lau Islands to the southeast of Fiji have strong historic and cultural links with Tonga. However, in essence, Polynesia is a term referring to one of the three parts of Oceania. Some islands of Polynesian origin are outside the triangle that geographically defines the region. The Phoenix Islands and Line Islands, most of which are part of Kiribati, are geographically Polynesian islands, tracing Polynesian languages places their prehistoric origins in the Malay Archipelago, and ultimately, in Taiwan. Between about 3000 and 1000 BC speakers of Austronesian languages began spreading from Taiwan into Island Southeast Asia, there are three theories regarding the spread of humans across the Pacific to Polynesia
4.
Nuku Hiva
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Nuku Hiva is the largest of the Marquesas Islands in French Polynesia, an overseas territory of France in the Pacific Ocean. It was formerly known as Île Marchand and Madison Island. Herman Melville wrote his book Typee based on his experiences in the Taipivai valley in the part of Nuku Hiva. Robert Louis Stevensons first landfall on his voyage on the Casco was at Hatiheu, on the side of Nuku Hiva. The coastline of western Nuku Hiva is characterized by a steep, but fairly regular coastline, indented occasionally by small bays leading to deep valleys, there are no villages on this side. The coastline of the part of the island has few places to land by sea. The north, on the hand, is indented by deep bays. Aakapa bay is not as large but has a village of the same name, the south has fewer bays, among which those of Taiohae, Taipivai, Hooumi, Hakaui and the bays of Hakaui and Hakatea both accessed by the same narrow entrance. On the western edge of Toovii rises Tekao, the islands highest peak, the western and northern edges of Toovii are a mountain ridge, which catches much of the rain that waters the island. Pine forest plantations covering large areas all around the crater of Toovii give an impression of the lower Alps and parts of Germany, Wales. In one place, Vaipō Waterfall, the water falls off a highland. The slopes of the western side of the island are much drier than the rest of the island. Nuku Hiva is administratively part of the commune of Nuku-Hiva, itself in the subdivision of the Marquesas Islands. The population in 2007 was 2,660 and this is substantially less than that encountered at the end of the 16th century when the Spaniards first sighted the island. Contacts with Europeans brought infections such as disease and influenza causing high mortality. The population is primarily Polynesian with a proportion of Europeans. At the 2002 census,92. 6% of Nuku Hivas residents were born in French Polynesia while 148 people, the primary diet of people tends to be breadfruit, taro, manioc, coconut and many kinds of fruit, which grow in abundance. Goats, fish and, more rarely, pigs, are the sources of meat
5.
Ua Pou
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Ua Pou is the third largest of the Marquesas Islands, in French Polynesia, an overseas territory of France in the Pacific Ocean. It is located about 50 km south of Nuku Hiva, in the northern Marquesas, the center of the island is characterized by four high basalt pillars that reach high above the surrounding mountains. The highest of these pillars, Mount Oave, reaches to 1,230 m above sea level and is the highest elevation in the Marquesas, the island covers an area of 106 square kilometres, and is located just northwest of the small island of Motu Oa. The population in 2007 was 2,157, the largest settlement is Hakahau, on Hakahau Bay, on the northeast coast. Administratively Ua Pou forms the commune of Ua-Pou, part of the subdivision of the Marquesas Islands. This commune consists solely of the island of Ua Pou and its offshore rocks, Ua Pou is the only major island that was unified under a single monarch prior to the arrival of European explorers. Prior to the unification, reportedly about 1585, there is evidence that the tribes of Ua Pou were sometimes united in war with the tribes of Te Ii on Nuku Hiva against those of Tai Pi Vai
6.
Ua Huka
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Ua Huka is one of the Marquesas Islands, in French Polynesia, an overseas territory of France in the Pacific Ocean. It is situated in the group of the archipelago, approximately 25 mi. to the east of Nuku Hiva. Ua Huka is sometimes also found spelled Roohka or Ua Huna, the first Western navigator to sight the island was U. S. Navy Capt. Joseph Ingraham in 1791. He named the island Washington Island in honor of U. S. President George Washington, other names for the island include Riou and Solide. See also Names of the Marquesas Islands, the spider genus Uahuka is named after this island. The island is shaped approximately like a crescent, with its concave edge facing the south, the land area is approximately 83 km². The center of the island is a plateau, deeply indented in places by narrow river valleys. The highest peak, Hitikau reaches an elevation of 884 metres, Ua Huka is a shield volcano that was emplaced between 2.2 and 2.4 million years ago. It is thought to have formed by a center of upwelling magma called the Marquesas hotspot, the island is served by Ua Huka Airport. Administratively Ua Huka forms the commune of Ua-Huka, part of the subdivision of the Marquesas Islands. This commune consists solely of the island of Ua Huka itself, the administrative centre of the commune is the settlement of Vaipaee, on the southern side of the island. The 2007 census showed a population of 571 inhabitants, residing in three villages, Vaipaee, Hane, and Hokatu, among the archæological remains at sites such as Tehavea and Meiaute are ancient petroglyphs and thousands of bird bones. The Pupuakeiha Arboretum consists of 42 acres planted with over 300 species of trees and it is hoped that one day this wealth of species will be able to be used to reforest the island. On the western end of the island are found a number of sea-caves
7.
Hiva Oa
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With its 320 square kilometres, Hiva Oa is the second largest island in the Marquesas Islands, in French Polynesia, an overseas territory of France in the Pacific Ocean. Located at 945 south latitude and 139 W longitude, it is the largest island of the southern Marquesas group, around 2,200 people reside on the island. A volcano, Temetiu, is Hiva Oas highest point with 1,200 metres, according to local religion, the gods created the Marquesas as their home. Therefore, all islands have names that are related with the building of a house - Hiva Oa means long ridgepole, administratively, Hiva Oa is part of the commune of Hiva-Oa, itself in the administrative subdivision of the Marquesas Islands. Atuona, on the coast of Hiva Oa island, is the centre of the commune. Atuona was formerly the seat of government for all of the Marquesas Islands, the island is famous as the final home of French painter Paul Gauguin and Belgian singer Jacques Brel, both of whom are buried in Calvary Cemetery, overlooking Atuona. It is also home to the largest tiki sculptures in French Polynesia, in late pre-European times, the island was nearly evenly divided into two provinces—Nuku in the west, and Pepane in the east. Hiva Oa is the largest and most fertile of the southern Marquesas islands, similar to all the larger Marquesas, Hiva Oa features steep cliffs abruptly rising from the ocean to a rugged interior spine of volcanic mountains, ridges, and deep, isolated valleys. Travel along the shoreline is by boat as most of the terrain is too rugged for roads. A few dirt roads traverse the interior and link seacoast villages, the outstanding geologic characteristic of Hiva Oa is the collapsed volcano Temetiu. Semi-circular Taa Oa bay, also called the Bay of Traitors, is in the crater of the volcano whose walls rise sharply 1,000 metres above the bay, within Taa Oa are Atuona Bay and adjacent Taha Uku which are the best anchorages on the island. Taha Uku has a protective seawall built in 1981, Hiva Oa is separated from the nearby island of Tahuata to its south by a 2.5 miles wide channel called Haava or the Canal de Bordelais. Temperatures in the Marquesas are stable year around, but precipitation is highly variable, precipitation is much greater on the north and east parts of the islands and much less on the western parts. Droughts, sometimes lasting years, are frequent and seem to be associated with the El Niño phenomena. The highest annual rainfall recorded in Atuona is 148.2 inches, in 2012, the population of Hiva Oa was 2,190, of which 1,845 lived in the commune of Acounda and 345 in the village of Puamau. The inhabitants speak the southern Marquesan language, related to other Polynesian languages, the first recorded sighting of Hiva Oa by the Europeans was by the Spanish expedition of Álvaro de Mendaña on 21 July 1595. French Polynesia Ha‘ava Gauguin Cultural Center in Atuona Hiva Oa in 1842, Adventures of a man in Chapter XVII
8.
Fatu Hiva
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Fatu Hiva is the southernmost island of the Marquesas Islands, in French Polynesia, an overseas territory of France in the Pacific Ocean. With Motu Nao as its closest neighbor, it is also the most isolated of the inhabited islands, Fatu Hiva is also the title of a book by explorer and archaeologist Thor Heyerdahl, in which he describes his stay on the island in the 1930s. The name of the island in Marquesan is Fatu Iva, however, the name was recorded by Europeans as Fatu Hiva, perhaps under the influence of other Marquesan islands containing the element Hiva and also because in French the letter h is silent. The spelling Fatu Hiva has now become official, the island was named Isla Magdalena by Spanish explorers in the 16th century, a name rarely used. The eastern coastline of Fatu Hiva is characterized by a number of narrow valleys, the largest of these valleys is at Uia. The western coastline has two significant bays, Hana Vave in the north, one of the most picturesque sites in the South Pacific, there are several smaller valleys between these two. The center of the island is a plateau which is covered largely by tall grasses and pandanus trees. To the south of the plateau, running to the south, is a ridge, called Tauauoho, its highest peak. Proceeding to the north and northwest from the plateau is a ridge called Fa‘e One. The first recorded sighting of Fatu Hiva by the Europeans was by the Spanish expedition of Álvaro de Mendaña on 21 July 1595, administratively Fatu Hiva forms the commune of Fatu-Hiva, part of the administrative subdivision of the Marquesas Islands. This commune consists solely of the island of Fatu Hiva itself, the administrative centre of the commune is the settlement of Omoa, on the south-western side of the island. The 2007 population of Fatu Hiva was 587, primarily spread across three villages, Hana Vave Omoa Uia French Polynesia Pacific Islands Thor Heyerdahl
9.
Mont Oave
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Mount Oave is a mountain and the highest point of the Marquesas Islands of French Polynesia. Oave is a mountain, located on Ua Pou island at 1,230 metres above sea level. The summit is a basalt pillar, with a topographic isolation of 846 kilometres, it is the 55th most isolated peak in the world. The mountain was featured on French postage stamps in 1979 and 1985
10.
French Polynesia
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It is composed of 118 geographically dispersed islands and atolls stretching over an expanse of more than 2,000 kilometres in the South Pacific Ocean. Its total land area is 4,167 square kilometres, among its 118 islands and atolls,67 are inhabited. Tahiti, which is located within the Society Islands, is the most populous island and it has more than 68% of the population of the islands in 2012. Although not a part of its territory, Clipperton Island was administered from French Polynesia until 2007. Following the Great Polynesian Migration, European explorers visited the islands of French Polynesia on several occasions, traders and whaling ships also visited. In 1842, the French took over the islands and established a French protectorate they called Etablissements des français en Océanie, in 1946, the EFOs became an overseas territory under the constitution of the French Fourth Republic, and Polynesians were granted the right to vote through citizenship. In 1957, the EFOs were renamed French Polynesia, French Polynesia as we know it today was one of the last places on Earth to be settled by humans. Scientists believe the Great Polynesian Migration happened around 1500 BC as Austronesian people went on a journey using celestial navigation to find islands in the South Pacific Ocean, the first islands of French Polynesia to be settled were the Marquesas Islands in about 200 BC. The Polynesians later ventured southwest and discovered the Society Islands around AD300, European encounters began in 1521 when Portuguese explorer Ferdinand Magellan, sailing at the service of the Spanish Crown, sighted Puka-Puka in the Tuāmotu-Gambier Archipelago. Over a century later, British explorer Samuel Wallis visited Tahiti in 1767, French explorer Louis Antoine de Bougainville also visited Tahiti in 1768, while British explorer James Cook arrived in 1769. A short-lived Spanish settlement was created in 1774, and for a time some maps bore the name Isla de Amat after Viceroy Amat, in 1772, Dutchman Jakob Roggeveen came across Bora Bora in the Society Islands. Christian missions began with Spanish priests who stayed in Tahiti for a year, protestants from the London Missionary Society settled permanently in Polynesia in 1797. King Pōmare II of Tahiti was forced to flee to Moorea in 1803, he, French Catholic missionaries arrived on Tahiti in 1834, their expulsion in 1836 caused France to send a gunboat in 1838. In 1842, Tahiti and Tahuata were declared a French protectorate, the capital of Papeetē was founded in 1843. In 1880, France annexed Tahiti, changing the status from that of a protectorate to that of a colony, the island groups were not officially united until the establishment of the French protectorate in 1889. In the 1880s, France claimed the Tuamotu Archipelago, which belonged to the Pōmare Dynasty. Having declared a protectorate over Tahuata in 1842, the French regarded the entire Marquesas Islands as French, in 1885, France appointed a governor and established a general council, thus giving it the proper administration for a colony. The islands of Rimatara and Rūrutu unsuccessfully lobbied for British protection in 1888, postage stamps were first issued in the colony in 1892
11.
French language
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French is a Romance language of the Indo-European family. It descended from the Vulgar Latin of the Roman Empire, as did all Romance languages, French has evolved from Gallo-Romance, the spoken Latin in Gaul, and more specifically in Northern Gaul. Its closest relatives are the other langues doïl—languages historically spoken in northern France and in southern Belgium, French was also influenced by native Celtic languages of Northern Roman Gaul like Gallia Belgica and by the Frankish language of the post-Roman Frankish invaders. Today, owing to Frances past overseas expansion, there are numerous French-based creole languages, a French-speaking person or nation may be referred to as Francophone in both English and French. French is a language in 29 countries, most of which are members of la francophonie. As of 2015, 40% of the population is in Europe, 35% in sub-Saharan Africa, 15% in North Africa and the Middle East, 8% in the Americas. French is the fourth-most widely spoken mother tongue in the European Union, 1/5 of Europeans who do not have French as a mother tongue speak French as a second language. As a result of French and Belgian colonialism from the 17th and 18th century onward, French was introduced to new territories in the Americas, Africa, most second-language speakers reside in Francophone Africa, in particular Gabon, Algeria, Mauritius, Senegal and Ivory Coast. In 2015, French was estimated to have 77 to 110 million native speakers, approximately 274 million people are able to speak the language. The Organisation internationale de la Francophonie estimates 700 million by 2050, in 2011, Bloomberg Businessweek ranked French the third most useful language for business, after English and Standard Mandarin Chinese. Under the Constitution of France, French has been the language of the Republic since 1992. France mandates the use of French in official government publications, public education except in specific cases, French is one of the four official languages of Switzerland and is spoken in the western part of Switzerland called Romandie, of which Geneva is the largest city. French is the language of about 23% of the Swiss population. French is also a language of Luxembourg, Monaco, and Aosta Valley, while French dialects remain spoken by minorities on the Channel Islands. A plurality of the worlds French-speaking population lives in Africa and this number does not include the people living in non-Francophone African countries who have learned French as a foreign language. Due to the rise of French in Africa, the total French-speaking population worldwide is expected to reach 700 million people in 2050, French is the fastest growing language on the continent. French is mostly a language in Africa, but it has become a first language in some urban areas, such as the region of Abidjan, Ivory Coast and in Libreville. There is not a single African French, but multiple forms that diverged through contact with various indigenous African languages, sub-Saharan Africa is the region where the French language is most likely to expand, because of the expansion of education and rapid population growth
12.
Volcano
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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. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology, at the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Most divergent plate boundaries are at the bottom of the oceans, therefore, most volcanic activity is submarine, black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the temperature of the overlying mantle wedge. This magma tends to be very viscous due to its high content, so it often does not reach the surface. When it does reach the surface, a volcano is formed, typical examples of this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume and this theory is currently under criticism, however. The most common perception of a volcano is of a mountain, spewing lava and poisonous gases from a crater at its summit, however. The features of volcanoes are more complicated and their structure. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have features such as massive plateaus
13.
France
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France, officially the French Republic, is a country with territory in western Europe and several overseas regions and territories. The European, or metropolitan, area of France extends from the Mediterranean Sea to the English Channel and the North Sea, Overseas France include French Guiana on the South American continent and several island territories in the Atlantic, Pacific and Indian oceans. France spans 643,801 square kilometres and had a population of almost 67 million people as of January 2017. It is a unitary republic with the capital in Paris. Other major urban centres include Marseille, Lyon, Lille, Nice, Toulouse, during the Iron Age, what is now metropolitan France was inhabited by the Gauls, a Celtic people. The area was annexed in 51 BC by Rome, which held Gaul until 486, France emerged as a major European power in the Late Middle Ages, with its victory in the Hundred Years War strengthening state-building and political centralisation. During the Renaissance, French culture flourished and a colonial empire was established. The 16th century was dominated by civil wars between Catholics and Protestants. France became Europes dominant cultural, political, and military power under Louis XIV, in the 19th century Napoleon took power and established the First French Empire, whose subsequent Napoleonic Wars shaped the course of continental Europe. Following the collapse of the Empire, France endured a succession of governments culminating with the establishment of the French Third Republic in 1870. Following liberation in 1944, a Fourth Republic was established and later dissolved in the course of the Algerian War, the Fifth Republic, led by Charles de Gaulle, was formed in 1958 and remains to this day. Algeria and nearly all the colonies became independent in the 1960s with minimal controversy and typically retained close economic. France has long been a centre of art, science. It hosts Europes fourth-largest number of cultural UNESCO World Heritage Sites and receives around 83 million foreign tourists annually, France is a developed country with the worlds sixth-largest economy by nominal GDP and ninth-largest by purchasing power parity. In terms of household wealth, it ranks fourth in the world. France performs well in international rankings of education, health care, life expectancy, France remains a great power in the world, being one of the five permanent members of the United Nations Security Council with the power to veto and an official nuclear-weapon state. It is a member state of the European Union and the Eurozone. It is also a member of the Group of 7, North Atlantic Treaty Organization, Organisation for Economic Co-operation and Development, the World Trade Organization, originally applied to the whole Frankish Empire, the name France comes from the Latin Francia, or country of the Franks
14.
Tahiti
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Tahiti is the largest island in the Windward group of French Polynesia, this overseas collectivity of the French Republic is sometimes referred to as a French overseas country. The island was formed from volcanic activity and is high and mountainous with surrounding coral reefs, the population is 183,645 inhabitants, making it the most populous island of French Polynesia and accounting for 68.5 percent of its total population. Tahiti is the economic, cultural and political centre of French Polynesia, the capital, Papeete, is located on the northwest coast with the only international airport in the region, Faaā International Airport, situated 5 km from the town centre. Tahiti was originally settled by Polynesians between 300 and 800 CE and they represent about 70 percent of the islands population with the rest made up of Europeans, Chinese and those of mixed heritage. The island was part of the Kingdom of Tahiti until its annexation by France in 1880, when it was proclaimed a colony of France, French is the only official language although the Tahitian language is widely spoken. Tahiti is the highest and largest island in French Polynesia lying close to Moorea island and it is located 4,400 kilometres south of Hawaii,7,900 km from Chile and 5,700 km from Australia. The island is 45 km across at its widest point and covers an area of 1,045 km2, the highest peak is Mont Orohena. Mount Roonui, or Mount Ronui in the southeast rises to 1,332 m, the island consists of two roughly round portions centred on volcanic mountains and connected by a short isthmus named after the small town of Taravao, situated there. The northwestern portion is known as Tahiti Nui, while the much smaller portion is known as Tahiti Iti or Taiarapū. Tahiti Nui is heavily populated along the coast, especially around the capital, the interior of Tahiti Nui is almost entirely uninhabited. Tahiti Iti has remained isolated, as its half is accessible only to those travelling by boat or on foot. The rest of the island is encircled by a road which cuts between the mountains and the sea. A scenic and winding road climbs past dairy farms and citrus groves with panoramic views. Tahitis landscape features lush rainforests and many rivers and waterfalls, including the Papenoo River on the side. November to April is the wet season, the wettest month of which is January with 13.2 in of rain in Papeetē, August is the driest with 1.9 inches. The average temperature ranges between 21 and 31 °C with little seasonal variation, the lowest and highest temperatures recorded in Papeete are 16 and 34 °C, respectively. The first Tahitians arrived from Southeast Asia in about 200 BCE and this hypothesis of an emigration from Southeast Asia is supported by a number of linguistic, biological and archaeological proofs. For example, the languages of Fiji and Polynesia all belong to the same Oceanic sub-group, Fijian-Polynesian, in 1769, for instance, James Cook mentions a great traditional ship in Tahiti that was 33 m long, and could be propelled by sail or paddles
15.
Eiao
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Eiao is the largest of the extreme northwestern Marquesas Islands. The island was discovered in 1791 by the American sea captain Joseph Ingraham, other names given to this island by Western explorers include Masse, Fremantle, and Robert. Eiao is administratively part of the commune of Nuku-Hiva, itself in the subdivision of the Marquesas Islands. The center of island is a high plateau, rising on the east side to 576 metres above sea level. There is one good anchorage, found on the side of the island at Vaituha. In the 1970s, the island was the site of extensive French military activity, before the creation of the reserve, the Eiao monarch, a bird in the order passeriformes, became extinct. In pre-European times, the bodies of chiefs from parts of Te Ii were taken to Eiao for burial, Eiao was at one time home to a Marquesan tribe called the Tuametaki. Stone tools, especially adzes, made from basalt have been found in sites on other islands. French Polynesia Louis Le Breton Marquesan Nature Reserves
16.
Hatutu
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Hatutu is a small island approximately 3 km northeast of Eiao in the northern Marquesas Islands. Hatutu is administratively part of the commune of Nuku-Hiva, itself in the subdivision of the Marquesas Islands. It consists of a central ridge, which runs the full 6.5 km length of the island. The ridge rises to heights up to 428 m above sea level, in 1992, Hatutu was declared a nature reserve, the Hatutu Nature Reserve. The island is an important nesting ground for the blue footed booby, and home to the endemic Hatutu Marquesan warbler
17.
Motu One (Marquesas Islands)
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Motu One is the name of a small sandbank with no vegetation located on the western edge of a coral reef. Motu One is the northernmost of the Marquesas Islands, located about 30 kilometres northeast of Eïao and 15 kilometres northeast of Hatutu and it is also the only island in the group that is not made of exposed volcanic material, being a calcareous coral reef on a volcanic plug. Motu One is administratively part of the commune of Nuku-Hiva, itself in the subdivision of the Marquesas. Although Motu One was reportedly visited by Marquesans, primarily on egg-collecting missions, the first Westerners to sight the islet were on the 1813-1814 voyage of the American commander Commodore David Porter, who named it Lincoln Island. Subsequent explorers also called it Sand Island, green sea turtles nest on Motu One. There is a stand of Porolithon that is unique in French Polynesia. There are a variety of pelagic birds nesting on the islets including a subspecies of the southern Marquesan reed warbler. Since 1992, the reef and island ecosystem have been protected as the Motu One Reserve. Marquesan Nature Reserves Société dOrnithologie de Polynésie MANU
18.
Motu Iti (Marquesas Islands)
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Motu Iti is one of the northern Marquesas Islands in French Polynesia. Located west-northwest from Nuku Hiva, Motu Iti is the site of extensive seabird rookeries, Motu Iti is administratively part of the commune of Nuku-Hiva, itself in the administrative subdivision of the Marquesas Islands. In 1814, four sailors from an American ship were stranded on the rocky island, one survived for three years until being rescued by a passing ship
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Fatu Huku
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Fatu Huku, also known as Fatu Uku, is a small island in the Marquesas Islands, approximately 30 kilometres north of Hiva Oa. Fatu Huku is less than 2 kilometres long and 1 kilometre wide and has an area of about 1.3 square kilometres Fatu Huku is located at 9. 43°S latitude and 138. 93°W longitude. It is administratively part of the commune of Hiva Oa in the subdivision of the Marquesas Islands. The island is essentially a rock, looming steep-sided out of the ocean. Coral is rare in the Marquesas but an ancient coral reef is found at the elevations of Fatu Hutu. Fatu Huku is a dry island compared with most high islands in Polynesia, the altitude is insufficient to capture much of the moisture from the predominantly easterly winds. The dryer conditions and steep terrain limit the variety of vegetation, forty-eight percent of the land, mostly on top on the plateau, is covered with Pisonia forest,21 percent is grassland, and 31 percent is sparsely vegetated rock. A few coconut trees inhabit coastal locations, unlike inhabited islands, Fatu Huku has few non-native species of plants and is inhabited by sea birds and imported goats and rats. Fatu Huku was likely only ever inhabited in legend, unreliability of water sources and lack of land suitable for agriculture were factors preventing any habitation. The story of the demigod Tana-Oa, patron of fishermen, says that the island was fertile and green, until the sea, jealous of its beauty. It is said that this is how the island came to have coral on its flat top, on the plateau are a number of small platforms, which were likely used in sacrificial ceremonies by the fishermen who frequented its waters in pre-European times
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Tahuata
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Tahuata is the smallest of the inhabited Marquesas Islands, in French Polynesia, an overseas territory of France in the Pacific Ocean. It is located 4 km to the south of the end of Hiva Oa, across the Canal du Bordelais. Administratively, Tahuata forms the commune of Tahuata, part of the subdivision of the Marquesas Islands. This commune consists solely of the island of Tahuata itself, the administrative centre of the commune is the settlement of Vaitahu, on the western side of the island. 69 km² The highest point on the island is Mount Amatea, the 2012 census population was 703. Archæological evidence indicates that Tahuata was inhabited by Polynesians as early as 200 CE, in later pre-European times, the tribes of Tahuata were allied with the tribes from the Nuku province of Hiva Oa, and the island was considered a dependency of that province. The first recorded sighting by Europeans was by the Spanish expedition of Álvaro de Mandaña on 22 July 1595 and they charted the island as Santa Cristina. They landed at Vaitahu that they named Madre de Dios, according to the Spanish accounts Tahuata had fowls, fish, sugar cane, plantains, nuts and fruits. The existent town was built on two sides of a space, the houses being of timber and intertwined canes. The people had large and well constructed sailing canoes and their tools were made of shells and fish bones. They used slings, stones, and lances as weapons, Tahuata was visited by Captain James Cook in 1774 and Admiral Dupetit-Thouars in 1842, who signed the treaty annexing the Marquesas Islands to France. Because there is insufficient level ground for even a small runway and this serves to give the island a feeling of much greater isolation, despite its proximity to Hiva Oa
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Mohotani
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Mohotani is an uninhabited island southeast of Hiva Oa and east of Tahuata in the southern Marquesas Islands. It has an area of 15 km², much of the islands sparse vegetation has been destroyed by feral goats and sheep, to the extent that following its rare rains, the sea around it is stained red from runoff. Early reports describes the island as fertile, with forest and fields, when Thor Heyerdahl visited the island in 1938, there were only a few goats and remains of deserted huts and villages. Mohotani is administratively part of the commune of Hiva-Oa, itself in the subdivision of the Marquesas Islands. In pre-European times, the island was considered part of the territory of the province of Pepane, in 1992, the island and its surrounding smaller islands were officially protected by the declaration of the Motane Nature Reserve. The first recorded signting of Mohotani by the Europeans was by the Spanish expedition of Álvaro de Mendaña on 21 July 1595 and they charted it as San Pedro. Eastern Pacific Lands, Tahiti and the Marquesas Islands
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Humboldt Current
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The Humboldt Current is a cold, low-salinity ocean current that flows north along the west coast of South America from the southern tip of Chile to northern Peru. Also called the Peru Current, it is an eastern boundary current flowing in the direction of the equator and it is the most productive marine ecosystem in the world, as well as the largest upwelling system. The Humboldt’s high rates of primary and secondary productivity support the world’s largest fisheries, approximately 18-20% of the world’s fish catch comes from the Humboldt Current LME. The species are pelagic, sardines, anchovies and jack mackerel. The LME’s high productivity supports other important fishery resources as well as marine mammals, the cold, nutrient-rich water brought to the surface by upwelling drives the system’s extraordinary productivity. Periodically, the upwelling that drives the system’s productivity is disrupted by the El Niño-Southern Oscillation event, when this occurs, fish abundance and distribution are significantly affected, often leading to stock crashes and cascading social and economic impacts. These events have led to changes, where sardines and anchovies have replaced each other periodically as the dominant species in the ecosystem. These species changes can have consequences for the fishing industry. The Humboldt has a cooling influence on the climate of Chile, Peru. It is also responsible for the aridity of Atacama Desert in northern Chile and coastal areas of Peru. Marine air is cooled by the current and thus is not conducive to generating precipitation
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Magma
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Besides molten rock, magma may also contain suspended crystals, dissolved gas and sometimes gas bubbles. Magma often collects in magma chambers that may feed a volcano or solidify underground to form an intrusion, magma is capable of intruding into adjacent rocks, extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock. Magma is a complex high-temperature fluid substance, temperatures of most magmas are in the range 700 °C to 1300 °C, but very rare carbonatite magmas may be as cool as 600 °C, and komatiite magmas may have been as hot as 1600 °C. Environments of magma formation and compositions are commonly correlated, environments include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Despite being found in such locales, the bulk of the Earths crust. Except for the outer core, most of the Earth takes the form of a rheid. Magma, as liquid, preferentially forms in high temperature, low pressure environments within several kilometers of the Earths surface, magma compositions may evolve after formation by fractional crystallization, contamination, and magma mixing. By definition rock formed of solidified magma is called igneous rock, melting of solid rocks to form magma is controlled by three physical parameters, temperature, pressure, and composition. Mechanisms are discussed in the entry for igneous rock, as a rock melts, its volume changes. When enough rock is melted, the small globules of melt link up, under pressure within the earth, as little as a fraction of a percent partial melting may be sufficient to cause melt to be squeezed from its source. The degree of melting is critical for determining what type of magma is produced. The degree of partial melting required to form a melt can be estimated by considering the relative enrichment of incompatible elements versus compatible elements, incompatible elements commonly include potassium, barium, cesium, and rubidium. Rock types produced by small degrees of melting in the Earths mantle are typically alkaline. Typically, primitive melts of this composition form lamprophyre, lamproite, kimberlite and sometimes nepheline-bearing mafic rocks such as alkali basalts, pegmatite may be produced by low degrees of partial melting of the crust. Some granite-composition magmas are eutectic melts, and they may be produced by low to high degrees of melting of the crust. At high degrees of melting of the crust, granitoids such as tonalite, granodiorite and monzonite can be produced. Being only the time in recorded history that magma had been reached, IDDP decided to invest in the hole. A cemented steel case was constructed in the hole with a perforation at the close to the magma
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Seamount
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A seamount is a mountain rising from the ocean seafloor that does not reach to the waters surface, and thus is not an island. Seamounts are typically formed from volcanoes that rise abruptly and are usually found rising from the seafloor to 1. They are defined by oceanographers as independent features that rise to at least 1,000 m above the seafloor, the peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface. Seamounts and guyots are most abundant in the North Pacific Ocean, in recent years, several active seamounts have been observed, for example Loihi in the Hawaiian Islands. Because of their abundance, seamounts are one of the most common marine ecosystems in the world, interactions between seamounts and underwater currents, as well as their elevated position in the water, attract plankton, corals, fish, and marine mammals alike. Their aggregational effect has been noted by the fishing industry. There are ongoing concerns on the impact of fishing on seamount ecosystems. 95% of ecological damage is done by bottom trawling, which scrapes whole ecosystems off seamounts, because of their large numbers, many seamounts remain to be properly studied, and even mapped. Bathymetry and satellite altimetry are two technologies working to close the gap, there have been instances where naval vessels have collided with uncharted seamounts, for example, Muirfield Seamount is named after the ship that struck it in 1973. Seamounts can be found in every ocean basin in the world, a seamount is technically defined as an isolated rise in elevation of 1,000 m or more from the surrounding seafloor, and with a limited summit area, of conical form. If small knolls, ridges and hills less than 1,000 m in height are included there are over 100,000 seamounts in the world ocean. Most seamounts are volcanic in origin, and thus tend to be found on oceanic crust near mid-ocean ridges, mantle plumes, and island arcs. Overall, seamount and guyot coverage is greatest as a proportion of area in the North Pacific Ocean. The Arctic Ocean has only 16 seamounts and no guyots, the 9,951 seamounts mapped cover an area of 8,088,550 km2. The largest seamount has an area of 15,500 km2, guyots cover a total area of 707,600 km2 and have an average area of 2,500 km2, more than twice the average size of seamounts. Nearly 50% of guyot area and 42% of the number of guyots occur in the North Pacific Ocean, the largest three guyots are all in the North Pacific, the Kuko Guyot, Suiko Guyot and the Pallada Guyot. Seamount chain redirects here, for a broader coverage related to this topic, Seamounts are often found in groupings or submerged archipelagos, a classic example being the Emperor Seamounts, an extension of the Hawaiian Islands
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Basalt
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Basalt is a common extrusive igneous rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. Flood basalt describes the formation in a series of basalt flows. By definition, basalt is an igneous rock with generally 45-55% silica and less than 10% feldspathoid by volume. Basalt commonly features a very fine-grained or glassy matrix interspersed with visible mineral grains, the average density is 3.0 gm/cm3. Basalt is defined by its content and texture, and physical descriptions without mineralogical context may be unreliable in some circumstances. Basalt is usually grey to black in colour, but rapidly weathers to brown or rust-red due to oxidation of its mafic minerals into hematite, although usually characterized as dark, basaltic rocks exhibit a wide range of shading due to regional geochemical processes. Due to weathering or high concentrations of plagioclase, some basalts can be quite light-coloured and these phenocrysts usually are of olivine or a calcium-rich plagioclase, which have the highest melting temperatures of the typical minerals that can crystallize from the melt. Basalt with a texture is called vesicular basalt, when the bulk of the rock is mostly solid. Gabbro is often marketed commercially as black granite and these ultramafic volcanic rocks, with silica contents below 45% are usually classified as komatiites. Agricola applied basalt to the black rock of the Schloßberg at Stolpen. Tholeiitic basalt is relatively rich in silica and poor in sodium, included in this category are most basalts of the ocean floor, most large oceanic islands, and continental flood basalts such as the Columbia River Plateau. Basalt rocks are in some cases classified after their content in High-Ti and Low-Ti varieties. High-Ti and Low-Ti basalts have been distinguished in the Paraná and Etendeka traps and it has greater than 17% alumina and is intermediate in composition between tholeiite and alkali basalt, the relatively alumina-rich composition is based on rocks without phenocrysts of plagioclase. Alkali basalt is relatively poor in silica and rich in sodium and it is silica-undersaturated and may contain feldspathoids, alkali feldspar and phlogopite. Boninite is a form of basalt that is erupted generally in back-arc basins. Ocean island basalt Lunar basalt On Earth, most basalt magmas have formed by melting of the mantle. Basalt commonly erupts on Io, the third largest moon of Jupiter, and has formed on the Moon, Mars, Venus. The crustal portions of oceanic tectonic plates are composed predominantly of basalt, produced from upwelling mantle below, the mineralogy of basalt is characterized by a preponderance of calcic plagioclase feldspar and pyroxene
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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
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Plateau
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Plateaus can be formed by a number of processes, including upwelling of volcanic magma, extrusion of lava, and erosion by water and glaciers. Magma rises from the mantle, causing the ground to swell upward, in way, large, flat areas of rock are uplifted. Plateaus can also be built up by lava spreading outward from cracks, plateaus can also be formed by the erosional processes of glaciers on mountain ranges, leaving them sitting between the mountain ranges. Water can also erode mountains and other landforms down into plateaus, volcanic plateaus are produced by volcanic activity. The Columbia Plateau in the northwestern United States is an example, dissected plateaus are highly eroded plateaus cut by rivers and broken by deep narrow valleys. Plateaus are classified according to their surrounding environment, intermontane plateaus are the highest in the world, bordered by mountains. The Tibetan Plateau is one such plateau, Piedmont plateaus are bordered on one side by mountains and on the other by a plain or a sea. The Piedmont Plateau of the Eastern United States between the Appalachian Mountains and the Atlantic Coastal Plain is an example, continental plateaus are bordered on all sides by plains or oceans, forming away from the mountains. The Tibetan plateau covers approximately 2,500,000 km2, the plateau is sufficiently high enough to reverse the Hadley cell convection cycles and to drive the monsoons of India towards the south. The second-highest plateau is the Deosai Plateau of the Deosai National Park at an elevation of 4,114 m. It is located in the Astore and Skardu districts of Gilgit-Baltistan, Deosai means the land of giants. The park protects an area of 3,000 km2 and it is known for its rich flora and fauna of the Karakoram-West Tibetan Plateau alpine steppe ecoregion. In spring it is covered by sweeps of wildflowers and a variety of butterflies. The highest point in Deosai is Deosai Lake, or Sheosar Lake from the Shina language meaning Blind lake near the Chilim Valley. The lake lies at an elevation of 4,142 m, one of the highest lakes in the world, and is 2.3 km long,1.8 km wide, and 40 m deep on average. Some other major plateaus in Asia are, Armenian Highlands, Iranian plateau, Anatolian Plateau, Mongolian Plateau, and the Deccan Plateau. This polar ice cap is so massive that the echolocation sound measurements of ice thickness have shown that parts of the Antarctic dry land surface have been pressed below sea level. Thus, if that same ice cap were removed, the large areas of the frozen white continent would be flooded by the surrounding Antarctic Ocean or Southern Ocean
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Andean Volcanic Belt
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The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador and Peru. It formed as a result of subduction of the Nazca Plate, the belt is subdivided into four main volcanic zones that are separated from each other by volcanic gaps. The volcanoes of the belt are diverse in terms of activity style, products, while some differences can be explained by which volcanic zone a volcano belongs to, there are significant differences within volcanic zones and even between neighboring volcanoes. Romeral in Colombia is the northernmost member of the Andean Volcanic Belt, South of latitude 49° S within the Austral Volcanic Zone volcanic activity decreases with the southernmost volcano Fueguino in Tierra del Fuego archipelago. The Andean Volcanic Belt is segmented into four areas of active volcanism. The Northern Volcanic Zone extends from Colombia to Ecuador and includes all volcanoes on the mainland of these countries. Of the zones volcanoes,55 are located in Ecuador while 19 are in Colombia, in Ecuador the volcanoes are located in the Cordillera Occidental and Cordillera Real while in Colombia they are located in Cordillera Central. The volcanic arc has formed due to subduction of the Nazca Plate under western South America, some volcanoes of the Northern Volcanic Zone, such as Galeras and Nevado del Ruiz that lie in densely populated highland areas, are major sources of hazards. It has been estimated that crustal thickness beneath this region varies from around 40 to perhaps more than 55 km, sangay is the southernmost volcano of the Northern Volcanic Zone. The Central Volcanic Zone is an arc in western South America. It is one of the four zones of the Andes. The Central Volcanic Zone extends from Peru to Chile and forms the boundary of the Altiplano plateau. The volcanic arc has formed due to subduction of the Nazca Plate under western South America along the Peru–Chile Trench, the CVZ is characterized by a continental crust that reaches a thickness of approximately 70 km. Within this zone there are 44 major and 18 minor volcanic centers that are considered to be active, other silicic systems are Los Frailes ignimbrite plateau in Bolivia, and the caldera complexes of Incapillo and Cerro Galán in Argentina. The South Volcanic Zone extends roughly from Central Chiles Andes at the latitude of Santiago, 33°S, to Cerro Arenales in Aysén Region at ca. 46°S, a distance of well over 870 mi, the arc has formed due to subduction of the Nazca Plate under the South American Plate along the Peru–Chile Trench. The southern end of the SVZ is marked by the Chile Triple Junction where the Chile Rise subducts under South America at the Taitao Peninsula giving origin to the Patagonian Volcanic Gap, further south lies the Austral Volcanic Zone. During the Pliocene the SVZ south of 38°S consisted of a volcanic arc
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Subduction
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Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another and is forced or sinks due to gravity into the mantle. Regions where this occurs are known as subduction zones. Rates of subduction are typically in centimeters per year, with the rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Plates include both oceanic crust and continental crust, stable subduction zones involve the oceanic lithosphere of one plate sliding beneath the continental or oceanic lithosphere of another plate due to the higher density of the oceanic lithosphere. That is, the lithosphere is always oceanic while the overriding lithosphere may or may not be oceanic. Subduction zones are sites that have a rate of volcanism, earthquakes. Subduction zones are sites of convective downwelling of Earths lithosphere, subduction zones exist at convergent plate boundaries where one plate of oceanic lithosphere converges with another plate. The descending slab, the plate, is over-ridden by the leading edge of the other plate. The slab sinks at an angle of approximately twenty-five to forty-five degrees to Earths surface and this sinking is driven by the temperature difference between the subducting oceanic lithosphere and the surrounding mantle asthenosphere, as the colder oceanic lithosphere is, on average, denser. At a depth of approximately 80–120 kilometers, the basalt of the oceanic crust is converted to a rock called eclogite. At that point, the density of the oceanic crust increases and provides additional negative buoyancy and it is at subduction zones that Earths lithosphere, oceanic crust, sedimentary layers and some trapped water are recycled into the deep mantle. Earth is so far the only planet where subduction is known to occur, subduction is the driving force behind plate tectonics, and without it, plate tectonics could not occur. Subduction zones dive down into the mantle beneath 55,000 kilometers of convergent plate margins, subduction zones burrow deeply but are imperfectly camouflaged, and geophysics and geochemistry can be used to study them. Not surprisingly, the shallowest portions of subduction zones are known best, subduction zones are strongly asymmetric for the first several hundred kilometers of their descent. They start to go down at oceanic trenches and their descents are marked by inclined zones of earthquakes that dip away from the trench beneath the volcanoes and extend down to the 660-kilometer discontinuity. Subduction zones are defined by the array of earthquakes known as the Wadati–Benioff zone after the two scientists who first identified this distinctive aspect. Subduction zone earthquakes occur at greater depths than elsewhere on Earth, such deep earthquakes may be driven by deep phase transformations, thermal runaway, the subducting basalt and sediment are normally rich in hydrous minerals and clays. Additionally, large quantities of water are introduced into cracks and fractures created as the slab bends downward
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Peru
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Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the west by the Pacific Ocean. Peruvian territory was home to ancient cultures spanning from the Norte Chico civilization in Caral, one of the oldest in the world, to the Inca Empire, the largest state in Pre-Columbian America. The Spanish Empire conquered the region in the 16th century and established a Viceroyalty with its capital in Lima, ideas of political autonomy later spread throughout Spanish America and Peru gained its independence, which was formally proclaimed in 1821. After the battle of Ayacucho, three years after proclamation, Peru ensured its independence, subsequently, the country has undergone changes in government from oligarchic to democratic systems. Peru has gone through periods of political unrest and internal conflict as well as periods of stability, Peru is a representative democratic republic divided into 25 regions. It is a country with a high Human Development Index score. Its main economic activities include mining, manufacturing, agriculture and fishing, the Peruvian population, estimated at 31.2 million in 2015, is multiethnic, including Amerindians, Europeans, Africans and Asians. The main spoken language is Spanish, although a significant number of Peruvians speak Quechua or other native languages and this mixture of cultural traditions has resulted in a wide diversity of expressions in fields such as art, cuisine, literature, and music. The name of the country may be derived from Birú, the name of a ruler who lived near the Bay of San Miguel, Panama. When his possessions were visited by Spanish explorers in 1522, they were the southernmost part of the New World yet known to Europeans, thus, when Francisco Pizarro explored the regions farther south, they came to be designated Birú or Perú. An alternative history is provided by the contemporary writer Inca Garcilasco de la Vega, son of an Inca princess, the Spanish Crown gave the name legal status with the 1529 Capitulación de Toledo, which designated the newly encountered Inca Empire as the province of Peru. Under Spanish rule, the country adopted the denomination Viceroyalty of Peru, the earliest evidences of human presence in Peruvian territory have been dated to approximately 9,000 BC. Andean societies were based on agriculture, using such as irrigation and terracing, camelid husbandry. Organization relied on reciprocity and redistribution because these societies had no notion of market or money, the oldest known complex society in Peru, the Norte Chico civilization, flourished along the coast of the Pacific Ocean between 3,000 and 1,800 BC. These early developments were followed by archaeological cultures that developed mostly around the coastal, the Cupisnique culture which flourished from around 1000 to 200 BC along what is now Perus Pacific Coast was an example of early pre-Incan culture. The Chavín culture that developed from 1500 to 300 BC was probably more of a religious than a political phenomenon, on the coast, these included the civilizations of the Paracas, Nazca, Wari, and the more outstanding Chimu and Mochica. Their capital was at Chan Chan outside of modern-day Trujillo, in the 15th century, the Incas emerged as a powerful state which, in the span of a century, formed the largest empire in pre-Columbian America with their capital in Cusco
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High island
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In geology, a high island or volcanic island is an island of volcanic origin. The term can be used to such islands from low islands. Volcanic islands normally arise above a so-called hotspot and this hampers or hinders human settlement on many low islands. Atoll Low island Volcanic arc Micronesian culture, High island and low island cultures at Britannica. com
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Low island
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A low island is, in geology, an island of coral origin. The term applies whether the island was formed as a result of sedimentation upon a reef or of the uplifting of such islands. The term is used to such islands from high islands. Low islands are the kind of islands which ring the lagoons of atolls, the two types of islands are often found in proximity to each other. This is especially the case among the islands of the South Pacific Ocean, low islands have poor, sandy soil and little fresh water, which makes them difficult to farm. They dont support human habitation as well as high islands, the people that do live on low islands survive mostly by fishing. Low islands usually have an oceanic climate, atoll High island Micronesian culture, High island and low island cultures at Britannica. com
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Shoal
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Often it refers to those submerged ridges, banks, or bars that rise near enough to the surface of a body of water as to constitute a danger to navigation. Shoals are also known as sandbanks, sandbars, or gravelbars, two or more shoals that are either separated by shared troughs or interconnected by past and or present sedimentary and hydrographic processes are referred to as a shoal complex. The term shoal is also used in a number of ways that can be similar or quite different from how it is used in the geologic, geomorphic. Shoals are characteristically long and narrow ridges and they can develop where a stream, river, or ocean current promotes deposition of sediment and granular material, resulting in localized shallowing of the water. Marine shoals also develop either by the in place drowning of barrier islands as the result of sea level rise or by the erosion. Shoals can appear as a coastal landform in the sea, where they are classified as a type of bank, or as fluvial landforms in rivers, streams. A shoal–sandbar may seasonally separate a smaller body of water from the sea, such as, Marine lagoons Brackish water estuaries Freshwater seasonal stream and river mouths and deltas. They are typically composed of sand, although they could be of any matter that the moving water has access to and is capable of shifting around. Wave shoaling is the process when surface waves move towards shallow water, such as a beach, they slow down, their wave height increases and this behavior is called shoaling, and the waves are said to shoal. The waves may or may not build to the point where they break, depending on how large they were to begin with, in particular, waves shoal as they pass over submerged sandbanks or reefs. This can be treacherous for boats and ships, shoaling can also diffract waves, so the waves change direction. For example, if waves pass over a bank which is shallower at one end than the other. Thus the wave fronts will refract, changing direction like light passing through a prism, refraction also occurs as waves move towards a beach if the waves come in at an angle to the beach, or if the beach slopes more gradually at one end than the other. Sandbars, also known as a trough bars, form where the waves are breaking, sometimes this occurs seaward of a trough. Sand carried by the moving bottom current is deposited where the current reaches the wave break. Other longshore bars may lie further offshore, representing the point of even larger waves. A harbor or river bar is a sedimentary deposit formed at an entrance or river mouth by. Where beaches are suitably mobile, or the river’s suspended and/or bed loads are large enough, deposition can build up a sandbar that completely blocks a river mouth and damming the river
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Coral
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Corals are marine invertebrates in the class Anthozoa of phylum Cnidaria. They typically live in colonies of many identical individual polyps. The group includes the important reef builders that inhabit tropical oceans, a coral group is a colony of myriad genetically identical polyps. Each polyp is an animal typically only a few millimeters in diameter. A set of tentacles surround a central mouth opening, an exoskeleton is excreted near the base. Over many generations, the colony creates a large skeleton that is characteristic of the species. Individual heads grow by reproduction of polyps. Corals also breed sexually by spawning, polyps of the same species release gametes simultaneously over a period of one to several nights around a full moon and these are commonly known as zooxanthellae and the corals that contain them are zooxanthellate corals. Such corals require sunlight and grow in clear, shallow water, other corals do not rely on zooxanthellae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,000 metres. Some have been found on the Darwin Mounds, north-west of Cape Wrath, Corals have also been found as far north as off the coast of Washington State and the Aleutian Islands. In his Scala Naturae, Aristotle classified corals as zoophyta, animals that had characteristics of plants and were therefore hypothetically in between animals and plants, the Persian polymath Al-Biruni classified sponges and corals as animals, arguing that they respond to touch. The phylogeny of Anthozoans is not clearly understood and a number of different models have been proposed, within the Hexacorallia, the sea anemones, coral anemones and stony corals may constitute a monophyletic grouping united by their eight-fold symmetry and cnidocyte trait. The Octocorallia appears to be monophyletic, and primitive members of this group may have been stolonate, the cladogram presented here comes from a 2014 study by Stampar et al. which was based on the divergence of mitochondrial DNA within the group and on nuclear markers. Corals are classified in the class Anthozoa of the phylum Cnidaria and they are divided into three subclasses, Hexacorallia, Octocorallia, and Ceriantharia. The Hexacorallia include the stony corals, the sea anemones and the zoanthids and these groups have polyps that generally have 6-fold symmetry. The Octocorallia include blue coral, soft corals, sea pens and these groups have polyps with 8-fold symmetry, each polyp having eight tentacles and eight mesenteries. Fire corals are not true corals, being in the order Anthomedusa of the class Hydrozoa, Corals are sessile animals in the class Anthozoa and differ from most other cnidarians in not having a medusa stage in their life cycle. The body unit of the animal is a polyp, most corals are colonial, the initial polyp budding to produce another and the colony gradually developing from this small start
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Reef
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A reef is a bar of rock, sand, coral or similar material, lying beneath the surface of water. Reefs may be up to 261 feet below the surface, artificial reefs such as shipwrecks are sometimes created to enhance physical complexity on generally featureless sand bottoms in order to attract a diverse assemblage of organisms, especially fish. There is a variety of reef types, including oyster reefs. These biotic reef types take on additional names depending upon how the reef lies in relation to the land, Reef types include fringing reef, barrier reefs, as well as atolls. A fringing reef is a reef that is attached to an island, a barrier reef forms a calcareous barrier around an island resulting in a lagoon between the shore and the reef. An atoll is a reef with no land present. The reef front is a high energy locale whereas the internal lagoon will be at an energy with fine grained sediments. One useful definition distinguishes reefs from mounds as follows, reefs are held up by a macroscopic skeletal framework. Coral reefs are an excellent example of this kind, corals and calcareous algae grow on top of one another and form a three-dimensional framework that is modified in various ways by other organisms and inorganic processes. By contrast, mounds lack a macroscopic skeletal framework, mounds are built by microorganisms or by organisms that dont grow a skeletal framework. A microbial mound might be built exclusively or primarily by cyanobacteria, excellent examples of biostromes formed by cyanobacteria occur in the Great Salt Lake of Utah, and in Shark Bay, Western Australia. Cyanobacteria do not have skeletons and individuals are microscopic, cyanobacteria encourage the precipitation or accumulation of calcium carbonate and can produce distinct sediment bodies in composition that have relief on the seafloor. Cyanobacterial mounds were most abundant before the evolution of shelly macroscopic organisms, bryozoans and crinoids, common contributors to marine sediments during the Mississippian, produced a very different kind of mound. Bryozoans are small and the skeletons of crinoids disintegrate, however, bryozoan and crinoid meadows can persist over time and produce compositionally distinct bodies of sediment with depositional relief. The Proterozoic Belt Supergroup contains evidence of microbial mat and dome structures similar to stromatolite reef complexes. Ancient reefs buried within stratigraphic sections are of considerable interest to geologists because they provide information about the location in Earths history. Corals, including some major extinct groups Rugosa and Tabulata, have been important reef builders through much of the Phanerozoic since the Ordovician Period. However, other groups, such as calcifying algae, especially members of the red algae Rhodophyta
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