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28-484: Maupiti is a volcanic island, and lies on the Society hotspot . It is estimated to be 3.9 - 4.5 million years old. The island is a "near atoll", consisting of a central volcanic peak surrounded by a lagoon and barrier reef with four motu : Auira, Pa'ao, Tuanai, Tiapaa and Pitiahe. The lagoon has an area of 27 square kilometres (10 square miles) and the central island has an area of 12 square kilometres (4.6 square miles) and

56-557: A maximum elevation of 372 metres (1,220 feet). There are ancient Polynesian archaeological artifacts dating from at least AD 850 in Maupiti. A burial site excavated in 1962 suggested early cultural links with New Zealand . The first European to arrive on the island was the Dutchman Jakob Roggeveen in 1722. Historically, the island has had strong cultural links with Bora Bora . Maupiti Airport , located on

84-805: A subduction zone cannot subduct much further than about 100 km (62 mi) before resurfacing. As a result, continental lithosphere is not recycled at subduction zones the way oceanic lithosphere is recycled. Instead, continental lithosphere is a nearly permanent feature of the Earth. Geoscientists can directly study the nature of the subcontinental mantle by examining mantle xenoliths brought up in kimberlite , lamproite , and other volcanic pipes . The histories of these xenoliths have been investigated by many methods, including analyses of abundances of isotopes of osmium and rhenium . Such studies have confirmed that mantle lithospheres below some cratons have persisted for periods in excess of 3 billion years, despite

112-466: A tectonic origin. According to this model, the Society and other volcanic chains in the south Pacific result from a system of fissures caused by intraplate stresses related to thermal contraction of the lithosphere , subduction -induced flow of the asthenosphere , and changes in the configuration of plate boundaries which have enabled pre-existing melt in the crust and shallow mantle to escape to

140-415: Is a thermal boundary layer for the convection in the mantle. The thickness of the mantle part of the oceanic lithosphere can be approximated as a thermal boundary layer that thickens as the square root of time. h ∼ 2 κ t {\displaystyle h\,\sim \,2\,{\sqrt {\kappa t}}} Here, h {\displaystyle h} is the thickness of

168-465: Is a volcanic hotspot in the south Pacific Ocean which is responsible for the formation of the Society Islands , an archipelago of fourteen volcanic islands and atolls spanning around 720 kilometres (450 mi) of the ocean which formed between 4.5 and <1 Ma . There are currently two main hypotheses concerning the cause of volcanic activity. The conventional view is that the hotspot

196-417: Is no thicker than the crust, but oceanic lithosphere thickens as it ages and moves away from the mid-ocean ridge. The oldest oceanic lithosphere is typically about 140 kilometres (87 mi) thick. This thickening occurs by conductive cooling, which converts hot asthenosphere into lithospheric mantle and causes the oceanic lithosphere to become increasingly thick and dense with age. In fact, oceanic lithosphere

224-408: Is the rigid, outermost rocky shell of a terrestrial planet or natural satellite . On Earth , it is composed of the crust and the lithospheric mantle , the topmost portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy . Earth's lithosphere, which constitutes

252-490: Is underlain by a mantle plume which has transported hot material from the lower mantle to the surface, creating the chain as the Pacific Plate has moved northwest over the plume. Several lines of evidence support this interpretation. Age progression along the chain is consistent with estimates of the velocity of plate motion. Seismic anomalies have been observed in the upper mantle and found to extend into

280-426: Is velocity of the lithospheric plate. Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years but after this becomes increasingly denser than asthenosphere. While chemically differentiated oceanic crust is lighter than asthenosphere, thermal contraction of the mantle lithosphere makes it more dense than the asthenosphere. The gravitational instability of mature oceanic lithosphere has

308-426: The ocean basins . Continental lithosphere is associated with continental crust (having a mean density of about 2.7 grams per cubic centimetre or 0.098 pounds per cubic inch) and underlies the continents and continental shelves. Oceanic lithosphere consists mainly of mafic crust and ultramafic mantle ( peridotite ) and is denser than continental lithosphere. Young oceanic lithosphere, found at mid-ocean ridges ,

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336-480: The thermal flux from lower to upper mantle is on the scale of a plume rather than a superplume. Evidence for the latter model includes seismic imaging of the lower mantle which reveals a large-scale low-velocity anomaly from the base of the mantle to around 1,000 kilometres (620 mi) depth, small-scale anomalies in the upper mantle which may be narrow plumes generated by the superplume and intermittent volcanic activity in south Pacific hotspots which contrasts with

364-438: The Earth." They have been broadly accepted by geologists and geophysicists. These concepts of a strong lithosphere resting on a weak asthenosphere are essential to the theory of plate tectonics . The lithosphere can be divided into oceanic and continental lithosphere. Oceanic lithosphere is associated with oceanic crust (having a mean density of about 2.9 grams per cubic centimetre or 0.10 pounds per cubic inch) and exists in

392-465: The Society hotspot. The other proposes a superplume with narrow conduits supplying several hotspots in the south Pacific. Evidence for the former model includes magnetotelluric imaging which finds conductivity anomalies of less than 150 kilometres (93 mi) in radius indicating a plume of limited extent and seismic imaging of the transition zone under the Society hotspot which shows a thinned area of less than 500 kilometres (310 mi) implying that

420-419: The asthenosphere deforms viscously and accommodates strain through plastic deformation . The thickness of the lithosphere is thus considered to be the depth to the isotherm associated with the transition between brittle and viscous behavior. The temperature at which olivine becomes ductile (~1,000 °C or 1,830 °F) is often used to set this isotherm because olivine is generally the weakest mineral in

448-523: The concept and introduced the term "lithosphere". The concept was based on the presence of significant gravity anomalies over continental crust, from which he inferred that there must exist a strong, solid upper layer (which he called the lithosphere) above a weaker layer which could flow (which he called the asthenosphere ). These ideas were expanded by the Canadian geologist Reginald Aldworth Daly in 1940 with his seminal work "Strength and Structure of

476-408: The continental lithosphere are billions of years old. Geophysical studies in the early 21st century posit that large pieces of the lithosphere have been subducted into the mantle as deep as 2,900 kilometres (1,800 mi) to near the core-mantle boundary, while others "float" in the upper mantle. Yet others stick down into the mantle as far as 400 kilometres (250 mi) but remain "attached" to

504-403: The continental plate above, similar to the extent of the old concept of "tectosphere" revisited by Jordan in 1988. Subducting lithosphere remains rigid (as demonstrated by deep earthquakes along Wadati–Benioff zone ) to a depth of about 600 kilometres (370 mi). Continental lithosphere has a range in thickness from about 40 kilometres (25 mi) to perhaps 280 kilometres (170 mi);

532-437: The effect that at subduction zones, oceanic lithosphere invariably sinks underneath the overriding lithosphere, which can be oceanic or continental. New oceanic lithosphere is constantly being produced at mid-ocean ridges and is recycled back to the mantle at subduction zones. As a result, oceanic lithosphere is much younger than continental lithosphere: the oldest oceanic lithosphere is about 170 million years old, while parts of

560-559: The hard and rigid outer vertical layer of the Earth, includes the crust and the lithospheric mantle (or mantle lithosphere), the uppermost part of the mantle that is not convecting. The lithosphere is underlain by the asthenosphere which is the weaker, hotter, and deeper part of the upper mantle that is able to convect. The lithosphere–asthenosphere boundary is defined by a difference in response to stress. The lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure, while

588-506: The motu of Tuanai, provides a connection to the rest of French Polynesia. The primary economic activity on Maupiti was noni production. Maupiti is administratively part of the commune (municipality) of Maupiti , itself in the administrative subdivision of the Leeward Islands . The main settlement is Vaiea. [REDACTED] Media related to Maupiti (atoll) at Wikimedia Commons Society hotspot The Society hotspot

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616-419: The oceanic mantle lithosphere, κ {\displaystyle \kappa } is the thermal diffusivity (approximately 1.0 × 10  m /s or 6.5 × 10  sq ft/min) for silicate rocks, and t {\displaystyle t} is the age of the given part of the lithosphere. The age is often equal to L/V, where L is the distance from the spreading centre of mid-oceanic ridge , and V

644-417: The persistent volcanism expected for individual plumes. Clouard and Bonneville 2001 have argued that certain features of the Society hotspot, such as the lack of an initial flood basalt at the old end of the chain, short-lived volcanic activity, and petrological and geochemical analysis of the lavas which reveals a number of shallow-source components, are inconsistent with the plume model and have proposed

672-491: The superplume model which propose small-scale intermittent “plumelets” generated by the superplume, and the petrology and geochemistry of the lavas may be due to subducted oceanic crust being sampled by the plume. 17°32′S 149°50′W  /  17.533°S 149.833°W  / -17.533; -149.833 Lithosphere A lithosphere (from Ancient Greek λίθος ( líthos )  'rocky' and σφαίρα ( sphaíra )  'sphere')

700-476: The surface. The timing of volcanic activity and orientation of the chain, both of which coincide closely with major alterations in plate boundary configurations and consequent changes in the lithospheric stress field and direction of asthenospheric counterflow, support this model. Some of the above features, however, can be accommodated by the plume model. The lack of initial flood basalt and short-lived activity, for example, are consistent with some versions of

728-605: The upper approximately 30 to 50 kilometres (19 to 31 mi) of typical continental lithosphere is crust. The crust is distinguished from the upper mantle by the change in chemical composition that takes place at the Moho discontinuity . The oldest parts of continental lithosphere underlie cratons , and the mantle lithosphere there is thicker and less dense than typical; the relatively low density of such mantle "roots of cratons" helps to stabilize these regions. Because of its relatively low density, continental lithosphere that arrives at

756-534: The upper mantle. The lithosphere is subdivided horizontally into tectonic plates , which often include terranes accreted from other plates. The concept of the lithosphere as Earth's strong outer layer was described by the English mathematician A. E. H. Love in his 1911 monograph "Some problems of Geodynamics" and further developed by the American geologist Joseph Barrell , who wrote a series of papers about

784-434: The uppermost lower mantle, implying that the passage of hot material from the lower to upper mantle is not hindered by the transition zone . Magnetotelluric imaging has found higher conductivity in the upper mantle under the active area southeast of Tahiti consistent with anomalously hot rising material. There are two competing versions of the mantle plume model. One version posits a narrow, discreet plume feeding only

#16983