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107-765: The Negros Trench is an oceanic trench located northeast of the Sulu Trench and west of Negros Island Region in Visayas , the trench is located in the Sunda Plate in the southwestern region of the Pacific Ocean . The depth of the Negros Trench is unknown, in contrast it's neighboring trench the Sulu Trench has a depth of 5,600. During the Early-Miocine , the Sunda Plate subducted below

214-606: A Free French committee and appointed Henri Sautot as governor. The Vichy government despatched a warship, Dumont d'Urville , at Pélicier's request, but soon deemed him incompetent and appointed an acting governor. By this time the Australian government had agreed to intervene and despatched HMAS Adelaide to oversee the installation of Sautot as governor. A stand-off between Dumont d'Urville and Adelaide followed, with Pélicier and other pro-Vichy officials ultimately deported to French Indochina. In 1941, some 300 men from

321-476: A volcanic arc . Much of the fluid trapped in sediments of the subducting slab returns to the surface at the oceanic trench, producing mud volcanoes and cold seeps . These support unique biomes based on chemotrophic microorganisms. There is concern that plastic debris is accumulating in trenches and threatening these communities. There are approximately 50,000 km (31,000 mi) of convergent plate margins worldwide. These are mostly located around

428-410: A coalition of several pro-independence groups. Kanak society has several layers of customary authority, from the 4,000–5,000 family-based clans to the eight customary areas ( aires coutumières ) that make up the territory. Clans are led by clan chiefs and constitute 341 tribes, each headed by a tribal chief. The tribes are further grouped into 57 customary chiefdoms ( chefferies ), each headed by

535-457: A difference in buoyancy. An increase in retrograde trench migration (slab rollback) (2–4 cm/yr) is a result of flattened slabs at the 660-km discontinuity where the slab does not penetrate into the lower mantle. This is the case for the Japan, Java and Izu–Bonin trenches. These flattened slabs are only temporarily arrested in the transition zone. The subsequent displacement into the lower mantle

642-607: A feature of the Earth's distinctive plate tectonics . They mark the locations of convergent plate boundaries , along which lithospheric plates move towards each other at rates that vary from a few millimeters to over ten centimeters per year. Oceanic lithosphere moves into trenches at a global rate of about 3 km (1.2 sq mi) per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to and about 200 km (120 mi) from

749-507: A head chief, and forming the administrative subdivisions of the customary areas. The Customary Senate is the assembly of the various traditional councils of the Kanaks, and has jurisdiction over the law proposals concerning the Kanak identity. The Customary Senate is composed of 16 members appointed by each traditional council, with two representatives per customary area. In its advisory role,

856-426: A high angle of repose. Over half of all convergent margins are erosive margins. Accretionary margins, such as the southern Peru-Chile, Cascadia, and Aleutians, are associated with moderately to heavily sedimented trenches. As the slab subducts, sediments are "bulldozed" onto the edge of the overriding plate, producing an accretionary wedge or accretionary prism . This builds the overriding plate outwards. Because

963-551: A meeting chaired by the French Prime Minister Édouard Philippe on 2 November 2017, to be held by November 2018. Voter list eligibility was the subject of a long dispute, but the details were resolved in an electoral list that granted automatic eligibility to voters of Kanak origin but excluded those of other origins who had not been longtime residents of the territory. The referendum was held on 4 November 2018 , with independence being rejected. Another referendum

1070-694: A motto, and a new design for its banknotes. In July 2010, the Congress of New Caledonia voted in favour of a wish to fly the Kanak flag of the independence movement FLNKS alongside the French tricolour , as dual flags of the territory . The wish, legally non-binding, proved controversial. A majority of New Caledonian communes, but not all, now fly both flags, the rest flying only the French Tricolour. The non-official adoption made New Caledonia one of

1177-475: A prominent elongated depression of the sea bottom, was first used by Johnstone in his 1923 textbook An Introduction to Oceanography . During the 1920s and 1930s, Felix Andries Vening Meinesz measured gravity over trenches using a newly developed gravimeter that could measure gravity from aboard a submarine. He proposed the tectogene hypothesis to explain the belts of negative gravity anomalies that were found near island arcs. According to this hypothesis,

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1284-597: A regiment of the Troupes de marine , the Régiment d'infanterie de marine du Pacifique . About 80 percent of the 700-member regiment is composed of soldiers on short-term (four month) deployments from metropolitan France. As of 2018, only about 30 personnel in the regiment were locally recruited. The naval forces incorporate several vessels of the French Navy including: one Floréal -class frigate , Vendémiaire ,

1391-625: A state of emergency; however, regional elections went ahead , and the FLNKS won control of three out of four provinces. The centre-right government elected in France in March 1986 began eroding the arrangements established under the Socialists, redistributing lands mostly without consideration of native land claims, resulting in over two-thirds going to Europeans and less than a third to the Kanaks. By

1498-506: A three-week exercise. In addition, some 855 personnel from the National Gendarmerie are stationed on the archipelago divided into 4 companies, 27 brigades and several specialized and mobile Gendarmerie units. During periods such the 2021 referendum on independence, these forces have been significantly reinforced with personnel deployed from metropolitan France. The air component includes two Écureuil helicopters while

1605-422: A violent reaction in 1878, when High Chief Ataï  [ fr ] of La Foa managed to unite many of the central tribes and launched a guerrilla war that killed 200 Frenchmen and 1,000 Kanaks. A second uprising  [ fr ] occurred in 1917, with Protestant missionaries like Maurice Leenhardt functioning as witnesses to the events of this war. Leenhardt would pen a number of ethnographic works on

1712-528: A zone of continental collision. Features analogous to trenches are associated with collision zones . One such feature is the peripheral foreland basin , a sediment-filled foredeep . Examples of peripheral foreland basins include the floodplains of the Ganges River and the Tigris-Euphrates river system . Trenches were not clearly defined until the late 1940s and 1950s. The bathymetry of

1819-645: Is Nouméa . New Caledonia was part of the continent Zealandia , which broke off from the supercontinent Gondwana between 79 million and 83 million years ago. The earliest traces of human presence in New Caledonia date back to the period when the Lapita culture was influential in large parts of the Pacific, c.  1600 –500 BC or 1300–200 BC. The Lapita were highly skilled navigators and agriculturists . The first settlements were concentrated around

1926-563: Is a group of islands in the southwest Pacific Ocean , 220 km (140 mi) southwest of Vanuatu and 1,210 km (750 mi) east of Australia . Located 16,100 km (10,000 mi) from Metropolitan France , it forms a sui generis collectivity of the French Republic , a legal status unique in overseas France and enshrined in a dedicated chapter of the French Constitution . The archipelago, part of

2033-507: Is also to be delivered to naval forces based in New Caledonia by 2025. The landing craft is to better support coastal and riverine operations in the territory. As of the latter 2010s, French naval aviation and air force elements in New Caledonia included two Navy Falcon 200 Gardian maritime surveillance aircraft (drawn from Flotilla 25F), which are to be replaced by the more modern Falcon 2000 Albatros starting in 2025, plus two Casa CN235 transport aircraft and three Puma helicopters from

2140-476: Is caused by slab pull forces, or the destabilization of the slab from warming and broadening due to thermal diffusion. Slabs that penetrate directly into the lower mantle result in slower slab rollback rates (~1–3 cm/yr) such as the Mariana arc, Tonga arcs. As sediments are subducted at the bottom of trenches, much of their fluid content is expelled and moves back along the subduction décollement to emerge on

2247-422: Is complex, with many thrust ridges. These compete with canyon formation by rivers draining into the trench. Inner trench slopes of erosive margins rarely show thrust ridges. Accretionary prisms grow in two ways. The first is by frontal accretion, in which sediments are scraped off the downgoing plate and emplaced at the front of the accretionary prism. As the accretionary wedge grows, older sediments further from

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2354-416: Is determined by the angle of repose of the overriding plate edge. This reflects frequent earthquakes along the trench that prevent oversteepening of the inner slope. As the subducting plate approaches the trench, it bends slightly upwards before beginning its plunge into the depths. As a result, the outer trench slope is bounded by an outer trench high . This is subtle, often only tens of meters high, and

2461-489: Is explained by a change in the density of the subducting plate, such as the arrival of buoyant lithosphere (a continent, arc, ridge, or plateau), a change in the subduction dynamics, or a change in the plate kinematics. The age of the subducting plates does not have any effect on slab rollback. Nearby continental collisions have an effect on slab rollback. Continental collisions induce mantle flow and extrusion of mantle material, which causes stretching and arc-trench rollback. In

2568-422: Is fully exposed on the ocean bottom. The central Chile segment of the trench is moderately sedimented, with sediments onlapping onto pelagic sediments or ocean basement of the subducting slab, but the trench morphology is still clearly discernible. The southern Chile segment of the trench is fully sedimented, to the point where the outer rise and slope are no longer discernible. Other fully sedimented trenches include

2675-554: Is further divided into 33 communes (municipalities). One commune, Poya , is divided between two provinces. The northern half of Poya, with the main settlement and most of the population, is part of the North Province, while the southern half of the commune, with only 210 inhabitants in 2019, is part of the South Province. New Caledonia is part of Zealandia , a fragment of the ancient Gondwana super-continent, which

2782-567: Is located west of the Visayan Islands . This trench moves 2–3 cm/year. Although there are vast areas of subduction zones, some authors have considered this region to have low seismic activity . There has been a decent amount of earthquakes with a magnitude ≥6.4 in the region, with the most recent occurring in 2011. It hit the trench in a depth of 19.0 km. Areas adjacent to the subduction zones have experienced large seismic activity. Oceanic trench Oceanic trenches are

2889-482: Is of diverse origins and varies by geography; in the North and Loyalty Islands Provinces , the indigenous Kanak people predominate, while the wealthy South Province contains significant populations of European ( Caldoches and Metropolitan French ), Kanak , and Polynesian (mostly Wallisian ) origin, as well as smaller groups of Southeast Asian , Pied-Noir , and North African heritage. The capital of New Caledonia

2996-425: Is part of Oceania . It is speculated that New Caledonia separated from Australia roughly 66 million years ago, subsequently drifting in a north-easterly direction, reaching its present position about 50 million years ago. The mainland is divided in length by a central mountain range whose highest peaks are Mont Panié (1,629 m or 5,344 ft) in the north and Mont Humboldt (1,618 m or 5,308 ft) in

3103-484: Is recorded as tectonic mélanges and duplex structures. Frequent megathrust earthquakes modify the inner slope of the trench by triggering massive landslides. These leave semicircular landslide scarps with slopes of up to 20 degrees on the headwalls and sidewalls. Subduction of seamounts and aseismic ridges into the trench may increase aseismic creep and reduce the severity of earthquakes. Contrariwise, subduction of large amounts of sediments may allow ruptures along

3210-467: Is strongly moderated by the oceanic influence and the trade winds that attenuate humidity, which can be close to 80%. The average annual temperature is 23 °C, with historical extremes of 2.3 and 39.1 °C (36.1 and 102.4 °F). The rainfall records show that precipitation differs greatly within the island. The 3,000 millimetres (120 in) of rainfall recorded in Galarino are three times

3317-412: Is typically located a few tens of kilometers from the trench axis. On the outer slope itself, where the plate begins to bend downwards into the trench, the upper part of the subducting slab is broken by bending faults that give the outer trench slope a horst and graben topography. The formation of these bending faults is suppressed where oceanic ridges or large seamounts are subducting into the trench, but

Negros Trench - Misplaced Pages Continue

3424-515: Is what generates slab rollback. When the deep slab section obstructs the down-going motion of the shallow slab section, slab rollback occurs. The subducting slab undergoes backward sinking due to the negative buoyancy forces causing a retrogradation of the trench hinge along the surface. Upwelling of the mantle around the slab can create favorable conditions for the formation of a back-arc basin. Seismic tomography provides evidence for slab rollback. Results demonstrate high temperature anomalies within

3531-680: The Maritime Gendarmerie deploys the patrol boat Dumbea in the territory. New Caledonia has been a member of the Pacific Community since 1983 with Nouméa the home of the organization's regional headquarters. Since 1986, the United Nations Committee on Decolonization has included New Caledonia on the United Nations list of non-self-governing territories . An independence referendum

3638-435: The 2012 French presidential election , the voter turnout in New Caledonia was 61.19%. For 25 years, the party system in New Caledonia was dominated by the anti-independence The Rally–UMP . This dominance ended with the emergence of a new party, Avenir Ensemble , also opposed to independence, but considered more open to dialogue with the Kanak movement, which is part of the Kanak and Socialist National Liberation Front ,

3745-535: The Baie d'Harcourt , flowing towards the northern point of the island along the western escarpment of the Mount Panié. Most of the island is covered by wet evergreen forests, while savannahs dominate the lower elevations. The New Caledonian lagoon, with a total area of 24,000 square kilometres (9,300 sq mi) is one of the largest lagoons in the world. The lagoon and the surrounding New Caledonia Barrier Reef

3852-629: The European Union . New Caledonia has a land area of 18,575 km (7,172 sq mi) divided into three provinces . The North and South Provinces are on the New Caledonian mainland, while the Loyalty Islands Province is a series of four inhabited islands off the east coast of mainland (from north to south: Ouvéa , Lifou , Tiga , and Maré ). New Caledonia's population of 271,407 (October 2019 census)

3959-771: The Melanesia subregion, includes the main island of Grande Terre , the Loyalty Islands , the Chesterfield Islands , the Belep archipelago, the Isle of Pines , and a few remote islets. The Chesterfield Islands are in the Coral Sea . French people, especially locals, call Grande Terre le Caillou ( pron. [lə kaju] , lit.   ' the stone ' ), a nickname also used more generally for

4066-792: The Philippine Mobile Belt , which would later form the Negros Trench. The Negros trench was formed from subduction of the Eurasian Plate underneath the Philippine Sea plate which initiated during the Early Miocene (23.03-20.44 million years ago), The trench was previously the site of a collision zone with the Palawan plate, which formed the Philippine Trench 8–9 million years ago, This trench

4173-551: The president of France . They have the right to vote in elections to the European Parliament . It is governed by a 54-member Territorial Congress , a legislative body composed of members of three provincial assemblies. The French State is represented in the territory by a High Commissioner . At a national level, New Caledonia is represented in the French Parliament by two deputies and two senators. At

4280-444: The shear stresses at the base of the overriding plate. As slab rollback velocities increase, circular mantle flow velocities also increase, accelerating extension rates. Extension rates are altered when the slab interacts with the discontinuities within the mantle at 410 km and 660 km depth. Slabs can either penetrate directly into the lower mantle , or can be retarded due to the phase transition at 660 km depth creating

4387-695: The 1930s. In June 1940, after the fall of France , the General Council of New Caledonia voted to reject the Vichy government and continue supporting the Allied military effort against Germany. However, the colonial governor Georges-Marc Pélicier promulgated the Vichy government's Constitutional Law , which sparked street demonstrations and an assassination attempt. By this time Caldoches had been in contact with Charles de Gaulle who encouraged them to form

Negros Trench - Misplaced Pages Continue

4494-572: The 1960 descent of the Bathyscaphe Trieste to the bottom of the Challenger Deep. Following Robert S. Dietz ' and Harry Hess ' promulgation of the seafloor spreading hypothesis in the early 1960s and the plate tectonic revolution in the late 1960s, the oceanic trench became an important concept in plate tectonic theory. Oceanic trenches are 50 to 100 kilometers (30 to 60 mi) wide and have an asymmetric V-shape, with

4601-711: The Air Force's 52 "Tontouta" Squadron. Prior to 2022, the frigate Vendémiaire operated the Alouette III helicopter . However, with the retirement of the type in 2022, it is being replaced by the Eurocopter Dauphin N3 . In 2022, the French Air Force demonstrated a capacity to reinforce the territory by deploying three Rafale fighters, supported by A400M transport aircraft and A330 MRTT Phénix tankers, from France to New Caledonia for

4708-470: The Aleutian trench. In addition to sedimentation from rivers draining into a trench, sedimentation also takes place from landslides on the tectonically steepened inner slope, often driven by megathrust earthquakes . The Reloca Slide of the central Chile trench is an example of this process. Convergent margins are classified as erosive or accretionary, and this has a strong influence on the morphology of

4815-626: The Cascadia subduction zone. Sedimentation is largely controlled by whether the trench is near a continental sediment source. The range of sedimentation is well illustrated by the Chilean trench. The north Chile portion of the trench, which lies along the Atacama Desert with its very slow rate of weathering, is sediment-starved, with from 20 to a few hundred meters of sediments on the trench floor. The tectonic morphology of this trench segment

4922-534: The Cayman Trough, which is a pull-apart basin within a transform fault zone, is not an oceanic trench. Trenches, along with volcanic arcs and Wadati–Benioff zones (zones of earthquakes under a volcanic arc) are diagnostic of convergent plate boundaries and their deeper manifestations, subduction zones . Here, two tectonic plates are drifting into each other at a rate of a few millimeters to over 10 centimeters (4 in) per year. At least one of

5029-763: The Customary Senate must be consulted on law proposals "concerning the Kanak identity" as defined in the Nouméa Accord. It also has a deliberative role on law proposals that would affect identity, the civil customary statute, and the land system. A new president is appointed each year in August or September, and the presidency rotates between the eight customary areas. Kanak people have recourse to customary authorities regarding civil matters such as marriage, adoption, inheritance, and some land issues. The French administration typically respects decisions made in

5136-412: The Earth. The trench asymmetry reflects the different physical mechanisms that determine the inner and outer slope angle. The outer slope angle of the trench is determined by the bending radius of the subducting slab, as determined by its elastic thickness. Since oceanic lithosphere thickens with age, the outer slope angle is ultimately determined by the age of the subducting slab. The inner slope angle

5243-513: The Kanak of New Caledonia. Noël of Tiamou led the 1917 rebellion, which resulted in a number of orphaned children, one of whom was taken into the care of Protestant missionary Alphonse Rouel. This child, Wenceslas Thi, would become the father of Jean-Marie Tjibaou (1936–1989). Europeans brought new diseases such as smallpox and measles , which caused the deaths of many natives. The Kanak population declined from around 60,000 in 1878 to 27,100 in 1921, and their numbers did not increase again until

5350-737: The Loyalty Islands were first visited between 1793 and 1796 when Mare, Lifou, Tiga, and Ouvea were mapped by English whaler William Raven . Raven encountered the island, then named Britania, and today known as Maré (Loyalty Is.), in November 1793. From 1796 until 1840, only a few sporadic contacts with the archipelago were recorded. About 50 American whalers left record of being in the region (Grande Terre, Loyalty Is., Walpole and Hunter) between 1793 and 1887. Contacts with visiting ships became more frequent after 1840, because of their interest in sandalwood . As trade in sandalwood declined, it

5457-596: The Makran Trough, where sediments are up to 7.5 kilometers (4.7 mi) thick; the Cascadia subduction zone, which is completed buried by 3 to 4 kilometers (1.9 to 2.5 mi) of sediments; and the northernmost Sumatra subduction zone, which is buried under 6 kilometers (3.7 mi) of sediments. Sediments are sometimes transported along the axis of an oceanic trench. The central Chile trench experiences transport of sediments from source fans along an axial channel. Similar transport of sediments has been documented in

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5564-744: The Pacific Ocean, but are also found in the eastern Indian Ocean , with a few shorter convergent margin segments in other parts of the Indian Ocean, in the Atlantic Ocean, and in the Mediterranean. They are found on the oceanward side of island arcs and Andean-type orogens . Globally, there are over 50 major ocean trenches covering an area of 1.9 million km or about 0.5% of the oceans. Trenches are geomorphologically distinct from troughs . Troughs are elongated depressions of

5671-943: The abuses of blackbirding and 'recruitment' strategies on the coastlines. The first missionaries from the London Missionary Society and the Marist Brothers arrived in the 1840s. In 1849, the crew of the American ship Cutter was killed and eaten by the Pouma clan. Human cannibalism was widespread throughout New Caledonia. On 24 September 1853, under orders from Emperor Napoleon III , Admiral Febvrier Despointes took formal possession of New Caledonia. Captain Louis-Marie-François Tardy de Montravel founded Port-de-France (Nouméa) on 25 June 1854. A few dozen free settlers settled on

5778-949: The anchor of la Coloniale , the BIM, to form the Bataillon de l'infanterie de marine et du Pacifique . The combined battalion formed part of the Gaulliste 1 Division Motorisée d'Infanterie / Division de Marche d'Infanterie , alongside three divisions from the French North African forces, in the French Expeditionary Corps during the Italian Campaign. They landed in Provence in 1944, when they were posted out and replaced by local French volunteers and résistants. Meanwhile, in March 1942, with

5885-479: The area of the Southeast Pacific, there have been several rollback events resulting in the formation of numerous back-arc basins. Interactions with the mantle discontinuities play a significant role in slab rollback. Stagnation at the 660-km discontinuity causes retrograde slab motion due to the suction forces acting at the surface. Slab rollback induces mantle return flow, which causes extension from

5992-428: The assault. The Matignon Agreements , signed on 26 June 1988, ensured a decade of stability. The Nouméa Accord , signed 5 May 1998, set the groundwork for a 20-year transition that gradually transfers competences to the local government. Following the timeline set by the Nouméa Accord that stated a vote must take place by the end of 2018, the groundwork was laid for a referendum on full independence from France at

6099-846: The assistance of Australia, New Caledonia became an important Allied base, and the main South Pacific Fleet base of the United States Navy in the South Pacific moved to Nouméa in 1942–1943. The fleet that turned back the Japanese Navy in the Battle of the Coral Sea in May 1942 was based at Nouméa. American troops stationed on New Caledonia numbered as many as 50,000, matching the entire local population at

6206-472: The average of the west coast. There are also dry periods, because of the effects of El Niño . Between December and April, tropical depressions and cyclones can cause winds to exceed a speed of 100 kilometres per hour (62 mph), with gusts of 250 kilometres per hour (160 mph) and very abundant rainfall. The last cyclone affecting New Caledonia was Cyclone Niran , in March 2021. New Caledonia has many unique taxa, especially birds and plants. It has

6313-405: The belts were zones of downwelling of light crustal rock arising from subcrustal convection currents. The tectogene hypothesis was further developed by Griggs in 1939, using an analogue model based on a pair of rotating drums. Harry Hammond Hess substantially revised the theory based on his geological analysis. World War II in the Pacific led to great improvements of bathymetry, particularly in

6420-433: The bending faults cut right across smaller seamounts. Where the subducting slab is only thinly veneered with sediments, the outer slope will often show seafloor spreading ridges oblique to the horst and graben ridges. Trench morphology is strongly modified by the amount of sedimentation in the trench. This varies from practically no sedimentation, as in the Tonga-Kermadec trench, to completely filled with sediments, as with

6527-416: The coast and date back to the period between c. 1100 BC and AD 200. British explorer James Cook was one of the first Europeans to sight New Caledonia, on 4 September 1774, during his second voyage. He named it "New Caledonia ", as the northeast of the island reminded him of Scotland . The west coast of Grande Terre was approached by the Comte de Lapérouse in 1788, shortly before his disappearance, and

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6634-489: The customary system. However, their jurisdiction is sharply limited in penal matters, as some matters relating to the customary justice system, including the use of corporal punishment , are seen as clashing with the human rights obligations of France. The Armed Forces of New Caledonia ( French : Forces armées de Nouvelle-Calédonie , or FANC ) include about 2,000 soldiers, mainly deployed in Koumac , Nandaï , Tontouta , Plum , and Nouméa . The land forces consist of

6741-442: The early years of the trade, coercion was used to lure Melanesian islanders onto ships. In later years indenture systems were developed; however, when it came to the French slave trade, which took place between its Melanesian colonies of the New Hebrides and New Caledonia, very few regulations were implemented. This represented a departure from contemporary developments in Australia, since increased regulations were developed to mitigate

6848-461: The end of 1987, roadblocks, gun battles and the destruction of property culminated in the Ouvéa cave hostage taking , a dramatic hostage crisis just days before the 1988 French presidential election began. Pro-independence militants on Ouvéa killed four gendarmes and took 27 hostage. The military assaulted the cave to rescue the hostages. Nineteen Kanak hostage takers were killed and another three died in custody, while two soldiers were killed during

6955-409: The entire New Caledonia. Pro-independence Kanak parties use the name (la) Kanaky ( pron. [(la) kanaki] ) to refer to New Caledonia, a term coined in the 1980s from the ethnic name of the indigenous Melanesian Kanak people who make up 41% of New Caledonia's population. New Caledonia is one of the European Union's Overseas Countries and Territories (OCTs) , but it is not part of

7062-424: The exceptional biodiversity of New Caledonia and its threatened status has made it one of the most critical biodiversity hotspots on Earth. In 2001, Bruno Van Peteghem was awarded the Goldman Environmental Prize for his efforts on behalf of the Caledonian ecological protection movement in the face of "serious challenges" from Jacques Lafleur 's RPCR party. Progress has been made in a few areas in addressing

7169-426: The existence of back-arc basins . Forces perpendicular to the slab (the portion of the subducting plate within the mantle) are responsible for steepening of the slab and, ultimately, the movement of the hinge and trench at the surface. These forces arise from the negative buoyancy of the slab with respect to the mantle modified by the geometry of the slab itself. The extension in the overriding plate, in response to

7276-457: The failed Paris Commune of 1871, including Henri de Rochefort and Louise Michel . Between 1873 and 1876, 4,200 political prisoners were "relegated" to New Caledonia. Only 40 of them settled in the colony; the rest returned to France after being granted amnesty in 1879 and 1880. In 1864, nickel was discovered on the banks of the Diahot River ; with the establishment of the Société Le Nickel in 1876, mining began in earnest. To work

7383-423: The few countries or territories in the world with two flags. The decision to wish for the use of two flags has been a constant battleground between the two sides and led the coalition government to collapse in February 2011. The institutional organization is the result of the organic law and ordinary law passed by the Parliament on 16 February 1999. The archipelago is divided into three provinces: New Caledonia

7490-427: The fundamental plate-tectonic structure is still an oceanic trench. Some troughs look similar to oceanic trenches but possess other tectonic structures. One example is the Lesser Antilles Trough, which is the forearc basin of the Lesser Antilles subduction zone . Also not a trench is the New Caledonia trough, which is an extensional sedimentary basin related to the Tonga-Kermadec subduction zone . Additionally,

7597-440: The impact caused by the COVID-19 pandemic ; when the French government declined to do so, they called for a boycott. This led to 96% of voters choosing to stay with France. In May 2024, riots broke out amid debate over a proposed electoral reform in the territory. New Caledonia is a territory sui generis to which France has gradually transferred certain powers. As such its citizens have French nationality and vote for

7704-462: The inner slope as mud volcanoes and cold seeps . Methane clathrates and gas hydrates also accumulate in the inner slope, and there is concern that their breakdown could contribute to global warming . The fluids released at mud volcanoes and cold seeps are rich in methane and hydrogen sulfide , providing chemical energy for chemotrophic microorganisms that form the base of a unique trench biome . Cold seep communities have been identified in

7811-431: The inner slope of the trench. Erosive margins, such as the northern Peru-Chile, Tonga-Kermadec, and Mariana trenches, correspond to sediment-starved trenches. The subducting slab erodes material from the lower part of the overriding slab, reducing its volume. The edge of the slab experiences subsidence and steepening, with normal faulting. The slope is underlain by relative strong igneous and metamorphic rock, which maintains

7918-451: The inner trench slopes of the western Pacific (especially Japan ), South America, Barbados, the Mediterranean, Makran, and the Sunda trench. These are found at depths as great as 6,000 meters (20,000 ft). The genome of the extremophile Deinococcus from Challenger Deep has sequenced for its ecological insights and potential industrial uses. Because trenches are the lowest points in

8025-411: The mantle suggesting subducted material is present in the mantle. Ophiolites are viewed as evidence for such mechanisms as high pressure and temperature rocks are rapidly brought to the surface through the processes of slab rollback, which provides space for the exhumation of ophiolites . Slab rollback is not always a continuous process suggesting an episodic nature. The episodic nature of the rollback

8132-589: The mines the French imported labourers from neighbouring islands and from the New Hebrides, and later from Japan , the Dutch East Indies , and French Indochina . The French government also attempted to encourage European immigration, without much success. The indigenous Kanak people were excluded from the French economy and from mining work, and ultimately confined to reservations. This sparked

8239-457: The near future due to the accord, which states that "a name, a flag, an anthem, a motto, and the design of banknotes will have to be sought by all parties together, to express the Kanak identity and the future shared by all parties." To date, however, there has been no consensus on a new name for the territory, although Kanak Republic is popular among 40% of the population. New Caledonia has increasingly adopted its own symbols, choosing an anthem,

8346-579: The ocean floor, there is concern that plastic debris may accumulate in trenches and endanger the fragile trench biomes. Recent measurements, where the salinity and temperature of the water was measured throughout the dive, have uncertainties of about 15 m (49 ft). Older measurements may be off by hundreds of meters. (*) The five deepest trenches in the world New Caledonia New Caledonia ( / ˌ k æ l ɪ ˈ d oʊ n i ə / KAL -ih- DOH -nee-ə ; French : Nouvelle-Calédonie [nuvɛl kaledɔni] )

8453-593: The ocean was poorly known prior to the Challenger expedition of 1872–1876, which took 492 soundings of the deep ocean. At station #225, the expedition discovered Challenger Deep , now known to be the southern end of the Mariana Trench . The laying of transatlantic telegraph cables on the seafloor between the continents during the late 19th and early 20th centuries provided further motivation for improved bathymetry. The term trench , in its modern sense of

8560-610: The onward voyage to Africa. They joined the other Free French (FF) battalions in Qastina in August, before moving to the Western Desert with the 1st FF Brigade ( 1 BFL ). There they were one of the four battalions who took part in the breakout after the Battle of Bir Hakeim in 1942. Their losses could not easily be replaced from the Pacific and they were therefore amalgamated with the Frenchmen of another battalion wearing

8667-415: The overriding plate exerts a force against the subducting plate (FTS). The slab pull force (FSP) is caused by the negative buoyancy of the plate driving the plate to greater depths. The resisting force from the surrounding mantle opposes the slab pull forces. Interactions with the 660-km discontinuity cause a deflection due to the buoyancy at the phase transition (F660). The unique interplay of these forces

8774-511: The patrol and support vessel D'Entrecasteaux and Auguste Benebig , the lead ship of the Félix Éboué class of patrol vessels. The French Navy will further reinforce its offshore patrol capabilities in New Caledonia by deploying a second vessel of the Félix Éboué class ( Jean Tranape ) to the territory by 2025. One Engins de Débarquement Amphibie – Standards (EDA-S) landing craft

8881-512: The plates is oceanic lithosphere , which plunges under the other plate to be recycled in the Earth's mantle . Trenches are related to, but distinct from, continental collision zones, such as the Himalayas . Unlike in trenches, in continental collision zones continental crust enters a subduction zone. When buoyant continental crust enters a trench, subduction comes to a halt and the area becomes

8988-685: The protection of New Caledonia's ecological diversity from fire, industrial and residential development, unrestricted agricultural activity and mining (such as the judicial revocation of INCO 's mining licence in June 2006 owing to claimed abuses). In 2008, six lagoons of the New Caledonian barrier reef , the world's longest continuous barrier reef system, were inscribed on the UNESCO World Heritage List . New Caledonia's fauna and flora derive from ancestral species isolated in

9095-442: The region when it broke away from Gondwana many tens of millions of years ago. Not only endemic species have evolved here, but entire genera, families, and even orders are unique to the islands. More tropical gymnosperm species are endemic to New Caledonia than to any similar region on Earth. Of the 44 indigenous species of gymnosperms, 43 are endemic, including the only known parasitic gymnosperm ( Parasitaxus usta ). Also, of

9202-461: The richest diversity in the world per square kilometre. The biodiversity is caused by Grande Terre's central mountain range, which has created a variety of niches, landforms and micro-climates where endemic species thrive. Largely due to its nickel industry, New Caledonia emits a high level of carbon dioxide per person compared to other countries. In 2019, it emitted 55.25 tons of CO 2 per person, compared to 4.81 for France. The combination of

9309-525: The sea floor with steep sides and flat bottoms, while trenches are characterized by a V-shaped profile. Trenches that are partially infilled are sometimes described as troughs, for example the Makran Trough. Some trenches are completely buried and lack bathymetric expression as in the Cascadia subduction zone , which is completely filled with sediments. Despite their appearance, in these instances

9416-416: The sediments lack strength, their angle of repose is gentler than the rock making up the inner slope of erosive margin trenches. The inner slope is underlain by imbricated thrust sheets of sediments. The inner slope topography is roughened by localized mass wasting . Cascadia has practically no bathymetric expression of the outer rise and trench, due to complete sediment filling, but the inner trench slope

9523-405: The southeast. The east coast is covered by a lush vegetation. The west coast, with its large savannahs and plains suitable for farming, is a drier area. Many ore-rich massifs are found along this coast. The Diahot River is the longest river of New Caledonia, flowing for some 100 kilometres (62 mi). It has a catchment area of 620 km (240 sq mi) and opens north-westward into

9630-444: The steeper slope (8 to 20 degrees) on the inner (overriding) side of the trench and the gentler slope (around 5 degrees) on the outer (subducting) side of the trench. The bottom of the trench marks the boundary between the subducting and overriding plates, known as the basal plate boundary shear or the subduction décollement . The depth of the trench depends on the starting depth of the oceanic lithosphere as it begins its plunge into

9737-477: The subducting oceanic lithosphere is much younger, the depth of the Peru-Chile trench is around 7 to 8 kilometers (4.3 to 5.0 mi). Though narrow, oceanic trenches are remarkably long and continuous, forming the largest linear depressions on earth. An individual trench can be thousands of kilometers long. Most trenches are convex towards the subducting slab, which is attributed to the spherical geometry of

9844-416: The subduction décollement to propagate for great distances to produce megathrust earthquakes. Trenches seem positionally stable over time, but scientists believe that some trenches—particularly those associated with subduction zones where two oceanic plates converge—move backward into the subducting plate. This is called trench rollback or hinge retreat (also hinge rollback ) and is one explanation for

9951-399: The subsequent subhorizontal mantle flow from the displacement of the slab, can result in formation of a back-arc basin. Several forces are involved in the process of slab rollback. Two forces acting against each other at the interface of the two subducting plates exert forces against one another. The subducting plate exerts a bending force (FPB) that supplies pressure during subduction, while

10058-588: The territory proposed a five-year transition period and a referendum in 1989. In March 1984, the Front Indépendantiste, a Kanak resistance group, seized farms and the Kanak and Socialist National Liberation Front (FLNKS) formed a provisional government. In January 1985, the French Left-wing government offered sovereignty to the Kanaks and legal protection for European settlers. The plan faltered as violence escalated. The government declared

10165-695: The territory volunteered for service overseas. They were joined, in April, by 300 men from French Polynesia ('the Tahitians'), plus a handful from the French districts of the New Hebrides: together they formed the Bataillon du Pacifique . The Caledonians formed two of the companies, and the Polynesians the other two. In May 1941, they sailed to Australia and boarded the RMS ; Queen Elizabeth for

10272-653: The time. In 1946, New Caledonia became an overseas territory. By 1953, French citizenship had been granted to all New Caledonians, regardless of ethnicity. During the late 1940s and early 1950s, New Caledonia strengthened its economic links with Australia, particularly as turmoil within France and its empire weakened New Caledonia's traditional economic links to metropolitan France; New Caledonia supplied nickel to Australia in exchange for coal vital for smelting nickel. New Caledonian exports of iron ore and timber to Australia also increased during this time period. The European and Polynesian populations gradually increased in

10379-473: The trade in the early decades of the twentieth century involved kidnapping children from the Loyalty Islands to the Grand Terre for forced labour in plantation agriculture. New Caledonia's primary experience with blackbirding revolved around a trade from the New Hebrides (now Vanuatu) to the Grand Terre for labour in plantation agriculture, mines, as well as guards over convicts and in some public works. In

10486-455: The trench become increasingly lithified , and faults and other structural features are steepened by rotation towards the trench. The other mechanism for accretionary prism growth is underplating (also known as basal accretion ) of subducted sediments, together with some oceanic crust , along the shallow parts of the subduction decollement. The Franciscan Group of California is interpreted as an ancient accretionary prism in which underplating

10593-513: The trench, the angle at which the slab plunges, and the amount of sedimentation in the trench. Both starting depth and subduction angle are greater for older oceanic lithosphere, which is reflected in the deep trenches of the western Pacific. Here the bottoms of the Marianas and the Tonga–Kermadec trenches are up to 10–11 kilometers (6.2–6.8 mi) below sea level. In the eastern Pacific, where

10700-526: The west coast in the following years. New Caledonia became a penal colony in 1864, and from the 1860s until the end of the transportations in 1897, France sent about 22,000 criminals and political prisoners to New Caledonia. The Bulletin de la Société générale des prisons for 1888 indicates that 10,428 convicts, including 2,329 freed ones, were on the island as of 1 May 1888, by far the largest number of convicts detained in French overseas penitentiaries. The convicts included many Communards , arrested after

10807-429: The western Pacific. In light of these new measurements, the linear nature of the deeps became clear. There was a rapid growth of deep sea research efforts, especially the widespread use of echosounders in the 1950s and 1960s. These efforts confirmed the morphological utility of the term "trench." Important trenches were identified, sampled, and mapped via sonar. The early phase of trench exploration reached its peak with

10914-482: The years leading to the nickel boom of 1969–1972, and the indigenous Kanak Melanesians became a minority, though they were still the largest ethnic group. Between 1976 and 1988, a period referred to as "the Events" ( French : Les Événements ), conflicts between French government actions and the Kanak independence movement saw periods of serious violence and disorder. In 1983, a statute of "enlarged autonomy" for

11021-465: Was held in October 2020 , with voters once again choosing to remain a part of France. In the 2018 referendum, 56.7% of voters chose to remain in France. In the 2020 referendum, this percentage dropped with 53.4% of voters choosing to remain part of France. The third referendum was held on 12 December 2021. The referendum was boycotted by pro-independence forces, who argued for a delayed vote due to

11128-494: Was held on 4 October 2020. The result was that 53.26% of voters chose to remain with France. The third and last referendum permitted by the Nouméa Accord was held on 12 December 2021 , confirming New Caledonia as part of the French Republic with 96% voting "no" to independence after the vote was boycotted by the bulk of the Kanak population. The official name of the territory, Nouvelle-Calédonie , could be changed in

11235-573: Was held the following year, but independence was rejected by a large majority. Under the Nouméa Accord , signed in 1998 following a period of secessionist unrest in the 1980s and approved in a referendum , New Caledonia was granted special status. Twenty years after inception, the Nouméa Accord required an referendum on independence which was held on 4 November 2018. The result was that 56.9% of voters chose to remain with France. The Nouméa Accord required another independence referendum , which

11342-560: Was named a UNESCO World Heritage Site in 2008 for its exceptional beauty and marine biodiversity. In May 2023, there was an earthquake and tsunami in New Caledonia. This triggered a tsunami warning here as well as in other nearby countries. The climate is tropical , with a hot and humid season from November to March with temperatures between 27 and 30 °C (81 and 86 °F), and a cooler, dry season from June to August with temperatures between 20 and 23 °C (68 and 73 °F), linked by two short interstices. The tropical climate

11449-583: Was replaced by a new business enterprise, " blackbirding ", a euphemism for taking Melanesian or Western Pacific Islanders from New Caledonia, the Loyalty Islands, New Hebrides , New Guinea, and the Solomon Islands into slavery , indentured or forced labour in the sugarcane plantations in Fiji and Queensland by various methods of trickery and deception. Blackbirding was practised by both French and Australian traders, but in New Caledonia's case,

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