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62-540: Maud Rise formed part of the south-eastern African large igneous province (LIP), which developed south of Africa 100 to 94 million years ago (Ma). This LIP first formed 140-122 Ma east of South Africa where the Mozambique Ridge is now located. There it reached a maximum extent around 120 Ma when the African-Antarctic spreading zone was located below its eastern flank. Astrid Ridge

124-467: A supercontinent . In 2013 the CAMP's connection to the end-Triassic extinction , with major extinctions that enabled dinosaur domination of land, became more firmly established. Until 2013, the uncertainties in the geochronologic dates had been too coarse to confirm that the volcanic eruptions were correlated with major climate changes. The work by Blackburn et al. demonstrated a tight synchroneity between

186-579: A CAMP–related (about 200 Ma) dike in North Carolina. Whiteside et al. (2007) suggest that reverse polarity intervals in this dike could be of post Triassic age and correlated with the same events in Morocco. The Tr-J boundary is not officially defined, but most workers recognise it in continental strata by the last appearance of index taxa such as Ovalipollis ovalis , Vallasporites ignatii and Patinasporites densus or, in marine sections, by

248-618: A completely reliable constraint. CAMP lava flows of North America can be geochemically separated in three units: the older ones are classified as high titanium quartz normative (HTQ) basalts (TiO 2 = 1.0-1.3 wt%); these are followed by lava flows classified as low titanium quartz normative (LTQ) basalts (TiO 2 = ca. 0.8-1.3 wt%); and then by the youngest lava flow unit classified as high titanium iron quartz normative (HTIQ) basalts (TiO 2 = 1.4-1.6 wt%). According to Whiteside et al. (2007) , geochemical analyses based upon titanium, magnesium and silicon contents show

310-449: A consequence of the initial hot-spot activity in ocean basins as well as on continents. It is possible to track the hot spot back to the flood basalts of a large igneous province; the table below correlates large igneous provinces with the track of a specific hot spot. Eruptions or emplacements of LIPs appear to have, in some cases, occurred simultaneously with oceanic anoxic events and extinction events . The most important examples are

372-483: A great lateral extension and a maximum thickness up to 1 km. The basaltic flows occur on top of continental fluvial and lacustrine sedimentary units of Triassic age. Ar/ Ar data (on plagioclase) indicate for these basaltic units an absolute age of 198–200 Ma bringing this magmatic event undoubtedly close to the Triassic-Jurassic (Tr-J) boundary. Thus it is necessary to determine whether it straddles

434-423: A high proportion of dykes relative to country rocks, particularly when the width of the linear field is less than 100 km. The dykes have a typical width of 20–100 m, although ultramafic dykes with widths greater than 1 km have been reported. Dykes are typically sub-vertical to vertical. When upward flowing (dyke-forming) magma encounters horizontal boundaries or weaknesses, such as between layers in

496-517: A large proportion (>75%) of the total igneous volume has been emplaced. They are dominantly mafic, but also can have significant ultramafic and silicic components, and some are dominated by silicic magmatism." This definition places emphasis on the high magma emplacement rate characteristics of the LIP event and excludes seamounts, seamount groups, submarine ridges and anomalous seafloor crust. The definition has since been expanded and refined, and remains

558-702: A palynologic turnover, interpreted as the Tr-J boundary. In Morocco, two reversals have been detected in two lava flow sequences. Two distinct correlations between the Moroccan and the Newark magnetostratigraphy have been proposed. Marzoli et al. (2004) suggest that the Tr-J boundary is located above the lower reverse polarity level which is positioned more or less at the base of the Intermediate basalt unit of Morocco. These two levels can be correlated with chron E23r of

620-441: A sedimentary deposit, the magma can flow horizontally creating a sill. Some sill provinces have areal extents >1000 km. A series of related sills that were formed essentially contemporaneously (within several million years) from related dikes comprise a LIP if their area is sufficiently large. Examples include: Volcanic rifted margins are found on the boundary of large igneous provinces. Volcanic margins form when rifting

682-500: A solid convective mantle above a liquid core . The mantle's flow is driven by the descent of cold tectonic plates during subduction and the complementary ascent of mantle plumes of hot material from lower levels. The surface of the Earth reflects stretching, thickening and bending of the tectonic plates as they interact. Ocean-plate creation at upwellings, spreading and subduction are well accepted fundamentals of plate tectonics, with

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744-514: A symposium held at the 1999 Spring Meeting of the American Geophysical Union. The CAMP volcanic eruptions occurred about 201 million years ago and split into four pulses lasting for over ~600,000 years. The resulting large igneous province is, in area covered, the most extensive on Earth. The volume of magma flow of between two and six million cubic kilometres makes it one of the most voluminous as well. This geologic event

806-627: A volcanic province), and volcanic rifted margins . Mafic basalt sea floors and other geological products of 'normal' plate tectonics were not included in the definition. Most of these LIPs consist of basalt, but some contain large volumes of associated rhyolite (e.g. the Columbia River Basalt Group in the western United States); the rhyolite is typically very dry compared to island arc rhyolites, with much higher eruption temperatures (850 °C to 1000 °C) than normal rhyolites. Some LIPs are geographically intact, such as

868-554: A work in progress. Some new definitions of LIP include large granitic provinces such as those found in the Andes Mountains of South America and in western North America. Comprehensive taxonomies have been developed to focus technical discussions. Sub-categorization of LIPs into large volcanic provinces (LVP) and large plutonic provinces (LPP), and including rocks produced by normal plate tectonic processes, have been proposed, but these modifications are not generally accepted. LIP

930-432: Is a stub . You can help Misplaced Pages by expanding it . This article about a specific oceanic location or ocean current is a stub . You can help Misplaced Pages by expanding it . Large igneous province A large igneous province ( LIP ) is an extremely large accumulation of igneous rocks , including intrusive ( sills , dikes ) and extrusive ( lava flows, tephra deposits), arising when magma travels through

992-400: Is a common geochemical proxy used to detect massive volcanism in the geologic record, although its foolproofness has been called into question. Jameson Land Thulean Plateau Brazilian Highlands These LIPs are composed dominantly of felsic materials. Examples include: These LIPs are comprised dominantly of andesitic materials. Examples include: This subcategory includes most of

1054-462: Is accompanied by significant mantle melting, with volcanism occurring before and/or during continental breakup. Volcanic rifted margins are characterized by: a transitional crust composed of basaltic igneous rocks, including lava flows, sills, dikes, and gabbros , high volume basalt flows, seaward-dipping reflector sequences of basalt flows that were rotated during the early stages of breakup, limited passive-margin subsidence during and after breakup, and

1116-561: Is associated with subduction zones or mid-oceanic ridges, there are significant regions of long-lived, extensive volcanism, known as hotspots , which are only indirectly related to plate tectonics. The Hawaiian–Emperor seamount chain , located on the Pacific Plate , is one example, tracing millions of years of relative motion as the plate moves over the Hawaii hotspot . Numerous hotspots of varying size and age have been identified across

1178-481: Is associated with the Triassic–Jurassic extinction event . Although some connections among these basalts had long been recognized, in 1988 they were linked as constituting a single major flood basalt province . The basaltic sills of similar age (near 200 Ma, or earliest Jurassic) and composition (intermediate-Ti quartz tholeiite) which occur across the vast Amazon River basin of Brazil were linked to

1240-424: Is composed by a smaller number of lava flows (i.e., a lower volume) than the preceding one. These data suggest that they were created by five short magma pulses and eruption events, each one possibly <400 (?) years long. All lava flow sequences are characterized by normal polarity, except for a brief paleomagnetic reversal yielded by one lava flow and by a localized interlayered limestone in two distinct section of

1302-618: Is not now observable. The upper basalt layers of older LIPs may have been removed by erosion or deformed by tectonic plate collisions occurring after the layer is formed. This is especially likely for earlier periods such as the Paleozoic and Proterozoic . Giant dyke swarms having lengths over 300 km are a common record of severely eroded LIPs. Both radial and linear dyke swarm configurations exist. Radial swarms with an areal extent over 2,000 km and linear swarms extending over 1,000 km are known. The linear dyke swarms often have

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1364-652: Is now frequently used to also describe voluminous areas of, not just mafic, but all types of igneous rocks. Further, the minimum threshold to be included as a LIP has been lowered to 50,000 km . The working taxonomy, focused heavily on geochemistry, is: Because large igneous provinces are created during short-lived igneous events resulting in relatively rapid and high-volume accumulations of volcanic and intrusive igneous rock, they warrant study. LIPs present possible links to mass extinctions and global environmental and climatic changes. Michael Rampino and Richard Stothers cite 11 distinct flood basalt episodes—occurring in

1426-756: The Baffin Island flood basalt about 60 million years ago. Basalts from the Ontong Java Plateau show similar isotopic and trace element signatures proposed for the early-Earth reservoir. Seven pairs of hotspots and LIPs located on opposite sides of the earth have been noted; analyses indicate this coincident antipodal location is highly unlikely to be random. The hotspot pairs include a large igneous province with continental volcanism opposite an oceanic hotspot. Oceanic impacts of large meteorites are expected to have high efficiency in converting energy into seismic waves. These waves would propagate around

1488-574: The Deccan Traps of India were not antipodal to (and began erupting several Myr before) the Chicxulub impact in Mexico. In addition, no clear example of impact-induced volcanism, unrelated to melt sheets, has been confirmed at any known terrestrial crater. Aerally extensive dike swarms , sill provinces, and large layered ultramafic intrusions are indicators of LIPs, even when other evidence

1550-884: The Mesozoic Era, near the end of the Triassic and the beginning of the Jurassic periods. The subsequent breakup of Pangaea created the Atlantic Ocean , but the massive igneous upwelling provided a legacy of basaltic dikes , sills , and lavas now spread over a vast area around the present central North Atlantic Ocean, including large deposits in northwest Africa , southwest Europe , as well as northeast South America and southeast North America (found as continental tholeiitic basalts in subaerial flows and intrusive bodies ). The name and CAMP acronym were proposed by Andrea Marzoli (Marzoli et al. 1999) and adopted at

1612-556: The crust towards the surface. The formation of LIPs is variously attributed to mantle plumes or to processes associated with divergent plate tectonics . The formation of some of the LIPs in the past 500 million years coincide in time with mass extinctions and rapid climatic changes , which has led to numerous hypotheses about causal relationships. LIPs are fundamentally different from any other currently active volcanoes or volcanic systems. In 1992, Coffin and Eldholm initially defined

1674-726: The Deccan Traps ( Cretaceous–Paleogene extinction event ), the Karoo-Ferrar ( Pliensbachian-Toarcian extinction ), the Central Atlantic magmatic province ( Triassic-Jurassic extinction event ), and the Siberian Traps ( Permian-Triassic extinction event ). Several mechanisms are proposed to explain the association of LIPs with extinction events. The eruption of basaltic LIPs onto the earth's surface releases large volumes of sulfate gas, which forms sulfuric acid in

1736-620: The High Atlas CAMP. Palynological data from sedimentary layers samples at the base of four lava flow sequences constrain the onset of the CAMP, since there is no evidence of depositional hiatus or tectonic deformation at the bottom of the lava flow piles. The palynological assemblage observed in these basal layers is typical of Late Triassic age, similar to that of the uppermost Triassic sedimentary rocks of eastern North America. Samples from interlayered limestone in lava flows provided unreliable palynological data. One limestone bed from

1798-522: The LIP-triggered changes may be used as cases to understand current and future environmental changes. Plate tectonic theory explains topography using interactions between the tectonic plates, as influenced by viscous stresses created by flow within the underlying mantle . Since the mantle is extremely viscous, the mantle flow rate varies in pulses which are reflected in the lithosphere by small amplitude, long wavelength undulations. Understanding how

1860-1040: The Newark Basin, therefore the North American CAMP Basalts postdate the Tr–J boundary whereas part of the Moroccan CAMP was erupted within the Triassic. Contrarily, Whiteside et al. (2007) propose that these two levels could be earliest Jurassic intervals of reverse polarity not sampled in the Newark Basin Sequence (many more lava flows are present in the Moroccan Succession than in the Newark Basin), but observed in Early Jurassic sedimentary sequences of

1922-710: The Paris Basin of France. Reverse polarity intervals in America could be present within North Mountain (Fundy basin, Nova Scotia) which are poorly sampled even if previous magnetostratigraphy analysis in this sequence showed only normal polarity, or in the Scots Bay Member of the Fundy basin which have never been sampled. There is only one outcrop in the CAMP of America where reverse polarity is observable:

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1984-657: The Tr-J boundary climatic and biotic crisis that led to the mass-extinction . The North American portion of the CAMP lava flows crop out in various sections in the basins of Newark, Culpeper, Hartford, Deerfield, i.e. the Newark Supergroup in New England (USA), and in the Fundy Basin in Nova Scotia (Canada). The CAMP is here constituted by rare olivine - and common quartz-normative basalts showing

2046-552: The atmosphere; this absorbs heat and causes substantial cooling (e.g., the Laki eruption in Iceland, 1783). Oceanic LIPs can reduce oxygen in seawater by either direct oxidation reactions with metals in hydrothermal fluids or by causing algal blooms that consume large amounts of oxygen. Large igneous provinces are associated with a handful of ore deposit types including: Enrichment in mercury relative to total organic carbon (Hg/TOC)

2108-794: The basaltic Deccan Traps in India, while others have been fragmented and separated by plate movements, like the Central Atlantic magmatic province —parts of which are found in Brazil, eastern North America, and northwestern Africa. In 2008, Bryan and Ernst refined the definition to narrow it somewhat: "Large Igneous Provinces are magmatic provinces with areal extents > 1 × 10  km , igneous volumes > 1 × 10  km and maximum lifespans of ~50 Myr that have intraplate tectonic settings or geochemical affinities, and are characterised by igneous pulse(s) of short duration (~1–5 Myr), during which

2170-809: The best preserved and most complete basaltic lava piles are exposed. According to geochemical, petrographic and isotopic data four distinct tholeiitic basaltic units were recognized and can be placed throughout the Central High Atlas: Lower, Intermediate, Upper and Recurrent basalts. The Lower and Intermediate units are constituted by basaltic andesites , whereas the Upper and Recurrent units have basaltic composition. From Lower to Recurrent unit, we observe: Ages were determined by Ar/ Ar analysis on plagioclase . These data show indistinguishable ages (199.5±0.5 Ma) from Lower to Upper lava flows, from central to northern Morocco. Therefore, CAMP

2232-529: The boundary or not: if not, then the CAMP could not be a cause of the Late Triassic extinction event . For example, according to Whiteside et al. (2007) there are palynological, geochemical, and magnetostratigraphic evidences that the CAMP postdates the Tr-J boundary. In the Newark Basin , a magnetic reversal (E23r) is observed just below the oldest basalts and more or less in the same position as

2294-471: The core; roughly 15–20% have characteristics such as presence of a linear chain of sea mounts with increasing ages, LIPs at the point of origin of the track, low shear wave velocity indicating high temperatures below the current location of the track, and ratios of He to He which are judged consistent with a deep origin. Others such as the Pitcairn , Samoan and Tahitian hotspots appear to originate at

2356-461: The earliest volcanism and extinction of large populations using zircon uranium-lead (U-Pb) dating. They further demonstrated that the magmatic eruptions as well as the accompanying atmospheric changes were split into four pulses lasting for over ~600,000 years. Before that integration, two hypotheses were in debate. One hypothesis was based especially on studies on Triassic-Jurassic basins from Morocco where CAMP lava flows are outcropping, whereas

2418-520: The first appearance of the ammonite Psiloceras planorbis . In the Newark basin the palynological turnover event (hence the Tr-J boundary mass extinction) occurs below the oldest CAMP lava flows. The same can be said for the Fundy, Hartford and Deerfield Basins. In the investigated Moroccan CAMP sections (Central High Atlas Basin), sedimentary layers sampled immediately below the oldest basaltic lava flows, apparently contain Triassic taxa (e.g., P. densus ), and were thus defined as Triassic in age as at least

2480-401: The interaction between mantle flow and lithosphere elevation influences formation of LIPs is important to gaining insights into past mantle dynamics. LIPs have played a major role in the cycles of continental breakup, continental formation, new crustal additions from the upper mantle , and supercontinent cycles . Earth has an outer shell made of discrete, moving tectonic plates floating on

2542-553: The interior of western Africa westward for 2,500 kilometres (1,600 mi) through eastern and southern North America . If not the largest province by volume, the CAMP certainly encompasses the greatest area known, roughly 11,000,000 square kilometres (4,200,000 sq mi), of any continental large igneous province . Nearly all CAMP rocks are tholeiitic in composition, with widely separated areas where basalt flows are preserved, as well as large groups of diabase (dolerite) sills or sheets, small lopoliths , and dikes throughout

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2604-411: The large-scale plate tectonic circulation in which they are imbedded. Images reveal continuous but convoluted vertical paths with varying quantities of hotter material, even at depths where crystallographic transformations are predicted to occur. A major alternative to the plume model is a model in which ruptures are caused by plate-related stresses that fractured the lithosphere, allowing melt to reach

2666-457: The lower efficiency of kinetic energy conversion into seismic energy is not expected to create an antipodal hotspot. A second impact-related model of hotspot and LIP formation has been suggested in which minor hotspot volcanism was generated at large-body impact sites and flood basalt volcanism was triggered antipodally by focused seismic energy. This model has been challenged because impacts are generally considered seismically too inefficient, and

2728-461: The lowest lava flows . Still, a different interpretation is suggested by Whiteside et al. (2007) : the sampled sedimentary strata are quite deformed and this can mean that some sedimentary units could be lacking (eroded or structurally omitted). With respect to the Triassic pollens found in some sedimentary units above the Upper Unit basalts, they could have been reworked, so they don’t represent

2790-564: The order of 1 million cubic kilometers. In most cases, the majority of a basaltic LIP's volume is emplaced in less than 1 million years. One of the conundra of such LIPs' origins is to understand how enormous volumes of basaltic magma are formed and erupted over such short time scales, with effusion rates up to an order of magnitude greater than mid-ocean ridge basalts. The source of many or all LIPs are variously attributed to mantle plumes, to processes associated with plate tectonics or to meteorite impacts. Although most volcanic activity on Earth

2852-460: The other was based on end-Triassic extinction data from eastern North American basins and lava flows showing an extremely large turnover in fossil pollen, spores (sporomorphs), and vertebrates, respectively. The thickest lava flow sequences of the African CAMP are in Morocco, where there are basaltic lava piles more than 300 metres thick. The most-studied area is Central High Atlas , where

2914-603: The past 250 million years—which created volcanic provinces and oceanic plateaus and coincided with mass extinctions. This theme has developed into a broad field of research, bridging geoscience disciplines such as biostratigraphy , volcanology , metamorphic petrology , and Earth System Modelling . The study of LIPs has economic implications. Some workers associate them with trapped hydrocarbons. They are associated with economic concentrations of copper–nickel and iron. They are also associated with formation of major mineral provinces including platinum group element deposits and, in

2976-558: The presence of a lower crust with anomalously high seismic P-wave velocities in lower crustal bodies, indicative of lower temperature, dense media. The early volcanic activity of major hotspots, postulated to result from deep mantle plumes, is frequently accompanied by flood basalts. These flood basalt eruptions have resulted in large accumulations of basaltic lavas emplaced at a rate greatly exceeding that seen in contemporary volcanic processes. Continental rifting commonly follows flood basalt volcanism. Flood basalt provinces may also occur as

3038-598: The province in 1999. Remnants of CAMP have been identified on four continents (Africa, Europe, North America and South America) and consist of tholeiitic basalts formed during the opening of the Atlantic Ocean basin during the breakup of the Pangean supercontinent. The province has been described as extending within Pangaea from present-day central Brazil northeastward about 5,000 kilometres (3,100 mi) across western Africa , Iberia , and northwestern France , and from

3100-494: The province. Dikes occur in very large individual swarms with particular compositions and orientations. CAMP activity is apparently related to the rifting and breakup of Pangaea during the Late Triassic through Early Jurassic periods, and the enormous province size, varieties of basalt, and brief time span of CAMP magmatism invite speculation about mantle processes that could produce such a magmatic event as well as rift

3162-426: The provinces included in the original LIP classifications. It is composed of continental flood basalts, oceanic flood basalts, and diffuse provinces. Central Atlantic magmatic province The Central Atlantic magmatic province ( CAMP ) is the Earth's largest continental large igneous province , covering an area of roughly 11 million km . It is composed mainly of basalt that formed before Pangaea broke up in

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3224-407: The silicic LIPs, silver and gold deposits. Titanium and vanadium deposits are also found in association with LIPs. LIPs in the geological record have marked major changes in the hydrosphere and atmosphere , leading to major climate shifts and maybe mass extinctions of species. Some of these changes were related to rapid release of greenhouse gases from the lithosphere to the atmosphere. Thus

3286-465: The surface from shallow heterogeneous sources. The high volumes of molten material that form the LIPs is postulated to be caused by convection in the upper mantle, which is secondary to the convection driving tectonic plate motion. It has been proposed that geochemical evidence supports an early-formed reservoir that survived in the Earth's mantle for about 4.5 billion years. Molten material is postulated to have originated from this reservoir, contributing

3348-432: The surface topography. The convective circulation drives up-wellings and down-wellings in Earth's mantle that are reflected in local surface levels. Hot mantle materials rising up in a plume can spread out radially beneath the tectonic plate causing regions of uplift. These ascending plumes play an important role in LIP formation. When created, LIPs often have an areal extent of a few million square kilometers and volumes on

3410-458: The term "large igneous province" as representing a variety of mafic igneous provinces with areal extent greater than 100,000 km that represented "massive crustal emplacements of predominantly mafic (magnesium- and iron-rich) extrusive and intrusive rock, and originated via processes other than 'normal' seafloor spreading." That original definition included continental flood basalts , oceanic plateaus , large dike swarms (the eroded roots of

3472-472: The top of large, transient, hot lava domes (termed superswells) in the mantle. The remainder appear to originate in the upper mantle and have been suggested to result from the breakup of subducting lithosphere. Recent imaging of the region below known hotspots (for example, Yellowstone and Hawaii) using seismic-wave tomography has produced mounting evidence that supports relatively narrow, deep-origin, convective plumes that are limited in region compared to

3534-488: The top to the central High Atlas upper basalts yielded a Late Triassic palynological assemblage. However, the observed sporomorphs in this sample are rare and poorly preserved. All of these data indicate that the basaltic lava flows of the Central Atlantic magmatic province in Morocco were erupted at c. 200 Ma and spanned the Tr - J boundary. Thus, it is very possible that there is a connection between this magmatic event and

3596-399: The upwelling of hot mantle materials and the sinking of the cooler ocean plates driving the mantle convection. In this model, tectonic plates diverge at mid-ocean ridges , where hot mantle rock flows upward to fill the space. Plate-tectonic processes account for the vast majority of Earth's volcanism . Beyond the effects of convectively driven motion, deep processes have other influences on

3658-399: The world and reconverge close to the antipodal position; small variations are expected as the seismic velocity varies depending upon the route characteristics along which the waves propagate. As the waves focus on the antipodal position, they put the crust at the focal point under significant stress and are proposed to rupture it, creating antipodal pairs. When the meteorite impacts a continent,

3720-415: The world. These hotspots move slowly with respect to one another but move an order of magnitude more quickly with respect to tectonic plates, providing evidence that they are not directly linked to tectonic plates. The origin of hotspots remains controversial. Hotspots that reach the Earth's surface may have three distinct origins. The deepest probably originate from the boundary between the lower mantle and

3782-519: Was an intense, short magmatic event. Basalts of the Recurrent unit are slightly younger (mean age: 197±1 Ma) and represent a late event. Consistently, the Upper and Recurrent basalts are separated by a sedimentary layer that locally reaches a thickness of circa 80 m. According to magnetostratigraphic data, the Moroccan CAMP events were divided into five groups, differing in paleomagnetic orientations (declination and inclination). Each group

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3844-660: Was possibly part of this LIP as well. The LIP formation then continued intermittently until it finally reached its maximum extent south of South Africa 100 Ma. This volcanism ended 94 Ma, after which seafloor spreading divided the LIP into the Agulhas Plateau (south of South Africa), Northeast Georgia Rise (near South Georgia Island off South America), and Maud Rise. [REDACTED]  This article incorporates public domain material from "Maud Rise" . Geographic Names Information System . United States Geological Survey . This Antarctica -related article

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