Ol Doinyo Lengai

Last updated
Ol Doinyo Lengai
Oldoinyo Lengai
Lengai from Natron.jpg
Highest point
Elevation 2,962 m (9,718 ft) [1]
Prominence 1,360 m (4,460 ft)  OOjs UI icon edit-ltr-progressive.svg
Isolation 16.68 km (10.36 mi)  OOjs UI icon edit-ltr-progressive.svg
Coordinates 2°45′50″S35°54′50″E / 2.764°S 35.914°E / -2.764; 35.914 [1]
Geography
Tanzania relief location map.svg
Red triangle with thick white border.svg
Ol Doinyo Lengai
Parent range East African Rift
Geology
Mountain type Stratovolcano
Last eruption 2024 AD

Ol Doinyo Lengai is an active volcano in northern Tanzania. It consists of a volcanic cone with two craters, the northern of which has erupted during historical time. Uniquely for volcanoes on Earth, it has erupted natrocarbonatite, [2] an unusually low temperature and highly fluid type of magma. Eruptions in 2007–2008 affected the surrounding region.

Contents

Name

The Maasai and Sonjo people refer to the volcano as "The Mountain of God", associated with a myth of the abode of the god Engai, who withdrew there after being hit by a hunter with an arrow. [3] Other names are Basanjo, Donjo Ngai, Duenjo Ngai, Mongogogura, Mungogo wa Bogwe, and Oldonyo L'Engai. [4]

Geography and geomorphology

Ol Doinyo Lengai lies in the Arusha region of Tanzania, [5] 16 kilometres (9.9 mi) south of Lake Natron [6] and 120 kilometres (75 mi) northwest of the city of Arusha. [7] The summit was first explored between 1904 and 1915. [8] As of 2012, about 300,000 people live in the region, and livestock farming is the most important economic activity, although tourism is increasingly important. [9]

Ol Doinyo Lengai is a symmetric cone [1] that rises more than 1,800 metres (5,900 ft) above the surrounding rift valley. [10] It has two craters on either side of the mountain summit, [11] which is formed by a 110-metre (360-foot) high ridge. [12] The floor of the northern crater is covered with lava flows that resemble pahoehoe lavas. Small cones [lower-alpha 1] with sizes ranging from 2 metres (6 ft 7 in) to over 10 metres (33 ft) occur in the crater and produce lava flows from their summits and, when they collapse, from their flanks. [5] The southern crater is inactive and sometimes filled with water. [14] White volcanic ash deposits cover the slopes of the volcano, [11] which have large fractures on the western flank. [9] There are parasitic vents on Ol Doinyo Lengai's flanks, [15] such as Kirurum Crater on the western, the Nasira cones on the northern, Dorobo crater on the northeastern, and Oltatwa Crater on the eastern flank. [16]

There are deposits of past debris avalanches around the volcano, especially on its northern flank; [17] one such event has left a scar on the volcano's flanks. [18] Their occurrence may have been influenced by regional fault systems. [19]

Geology

Ol Doinyo Lengai is part of the Gregory Rift, [1] which is part of the active East African Rift. The East African Rift is a continental rift extending from eastern to southern Africa over a length of 4,000 kilometres (2,500 mi), [20] where there is high heat flow through a thinner crust. [21] In the Gregory Rift, spreading began about 1.2 million years ago [20] and is ongoing at a rate of about 3 millimetres per year (0.12 in/year). [22] The Natron Fault, the western boundary of the Gregory Rift in the area, passes just southwest of the volcano. [23]

The volcano is part of the Ngorongoro volcanic highland, a system of volcanoes that were active from the Miocene to present, and which includes the Ngorongoro and other volcanoes. [20] Over time, volcanic activity shifted northeastward to the present-day Ol Doinyo Lengai. [24] Other volcanoes in the area are Gelai to the northeast [lower-alpha 2] and Ketumbeine southeast of Ol Doinyo Lengai; further away are the Olduvai Gorge to the west and Kilimanjaro mountain east of the volcano. [10]

Composition

Most of the volcanic cone is formed by melilite, nephelinite, and phonolite. [lower-alpha 3] [26] Ol Doinyo Lengai is the only volcano on Earth known to have erupted carbonatitic lavas [lower-alpha 4] during historical times, [1] although these rocks make up only a small fraction of the volcano [15] and only occur in the northern crater; [lower-alpha 5] [27] they only recently appeared on the volcano. [13] The properties of Ol Doinyo Lengai's magmas have been used as an analogue for the conditions on carbon planets; these are planets which are rich in carbon. [21]

Chemical composition:

The carbonatite lavas are rapidly chemically modified by rainfall [30] or covered by deposits condensing from fumarolic gases, [31] yielding secondary minerals like calcite, gaylussite, nahcolite, pirssonite, shortite, thermonatrite, and trona, [32] including various chlorides, fluorides, [lower-alpha 6] and sulfates. [5] These rocks form crusts on the lava flows and within lava tubes. [13] Weathering on the silicic rocks has yielded zeoliths. [34]

The chemical composition of the erupted rocks is not steady, with an increase of silicic magma emplacement noted after 2007-2008, after an episode of increased spreading in the Gregory Rift. [35] The carbonatitic magmas appear to form through the separation of carbon-rich phases; the original magma is variously interpreted to be either nephelinitic or silicic. [21] The phonolites appear to have a separate origin from the other volcanic rocks. [36] There appear to be two magma reservoirs under the volcano, [37] and its plumbing system is complex, involving regional tectonic structures. [38]

Volcanic gases

Volcanic gas sampled at Ol Doinyo Lengai consists mostly of water vapor and carbon dioxide and originates in the mantle. [39] The volcano is a major source of volcanic carbon dioxide, producing about 80 kilograms per second (11,000 lb/min) of CO
2. [26]

Eruption history

Radiometric dates obtained by geologists for the start of volcanic eruptions at Ol Doinyo Lengai range from more than 500,000 to 22,000 years ago. [15] [40] It formed in two stages, Lengai I consisting of phonolite that forms about 60% of the volume of Ol Doinyo Lengai and crops out in its southern part, and Lengai II formed by nephelinitic rocks; [15] [41] [12] growth of the volcanic cone was complete about 15,000 years ago, [1] when the Naisiusiu Beds were emplaced in the Olduvai Gorge. [42] The volcano collapsed several times, including once between 850,000 and 135,000 years ago and another time between 50,000 and 10,000 years ago. [17] The oldest natrocarbonatite lavas date to 1,250 years before present. [39] An eruption 3,000-2,500 years before present produced a tephra fallout west of Ol Doinyo Lengai, that is presently being eroded by wind and forming dunes including the Shifting Sands of the Olduvai Gorge. [43] A large eruption deposited the Namorod Ash in the gorge, about 1,250 years ago, [34] and another about 600 years ago formed the so-called "Footprint Tuff". [34] Ol Doinyo Lengai is the only presently active volcano of the Gregory Rift. [10]

Records of eruptions go back to the 1880s. [44] [lower-alpha 7] The volcano is continually active, but there are seldom observations of its activity. [46] It erupts tephra and lava flows [11] from within the northern crater. [10] During the middle 20th century, the crater was about 200 metres (660 ft) deep; subsequently, lava flows filled it, and by 1998, lava was overflowing its rims. [1] The lava flows issue from cones within the crater and form lava ponds and lakes. [7] Explosive eruptions are less common, having been reported in 1917, 1940, 1966, [lower-alpha 8] 1983 and 1993. [39] [47] Oversteepened slopes produce landslides, [11] and erosion has cut gullies into volcanic deposits. [48] Steam jets have also been observed. [45]

There is evidence of underground magma intrusions. [22] Satellite observations have shown deformation of the volcano during eruptions, [49] and ground-based observations have identified movement in neighboring fault systems such as the Natron Fault caused by magma originating at Ol Doinyo Lengai. [50]

Recent eruptive period: 1983 and subsequent

Summit of Ol Doinyo Lengai in February, 2006 Pre-eruption aerial photo of Oldoinyo Lengai.jpg
Summit of Ol Doinyo Lengai in February, 2006

After a phase of quiescence, [26] renewed activity commenced in 1983 and continues [11] with several interruptions to this day. [51] During the 1983 eruption, ashfall occurred at tens of kilometers from the volcano. [26] The emission of a lava flow onto the western flank of Ol Doinyo Lengai in 2006 was accompanied by the formation of a pit crater on the summit. [52]

A large explosive eruption began on the 4 September 2007, producing a 3-kilometre (1.9 mi)-high eruption column [53] and a new crater 100 metres (330 ft) deep and 300 metres (980 ft) wide. [54] The explosive activity continued into 2008, when the volcano settled back into the effusion of lava flows; [53] a cinder cone formed in the northern crater during the eruption. [55] Aerosol clouds from the eruption [56] extended over east Africa. [57] The 2007 eruptions forced the evacuation of three villages [58] and disturbed air travel in the touristically important area; [59] livestock fatalities and injuries to people led to requests that the government of Tanzania enact access restrictions to the volcano [60] and to increased awareness of the threat formed by the volcano. [61] Wild animals such as flamingos were also impacted by the eruption. [59] The eruption was preceded in July by seismic activity, which was frequently mistaken for renewed eruptions, [62] and the intrusion of a dyke less than 20 kilometres (12 mi) from Ol Doinyo Lengai. [38]

General appearance of lava flows

White surface of solidified lava flows at Ol Doinyo Lengai, August 2001 Lava lengai.jpg
White surface of solidified lava flows at Ol Doinyo Lengai, August 2001

Lavas erupted by Ol Doinyo Lengai initially have brown or black colors, but within days [45] to hours become white like snow. [11] The lavas of Ol Doinyo Lengai have temperatures of 540–593 °C (1,004–1,099 °F); [5] they are so cold that during the day they look like mudflows [lower-alpha 9] or oil and glow only during the night. [7] They are highly fluid (reaching flow speeds of 1–5 metres per second (3.3–16.4 ft/s), [5] making them the most liquid of all known lavas, and form short (few tens of meters) and thin (few centimeters thick) lava flows. [11] More viscous flows containing silicic rocks have also been observed, for example during the 1993 eruption. [64]

Hazards

Potential threats from Ol Doinyo Lengai eruptions are scarcely established. [65] Threats from eruptions at Ol Doinyo Lengai include lahars, landslides, lava flows, pyroclastic flows, volcanic bombs, volcanic gas, and volcanic ash fall. [66] [9] Beginning in 2016, the volcano is being monitored by a seismometer and GNSS stations. [66]

Climate and vegetation

Vegetation in the area consists mostly of grassland, which reaches an elevation of 1,750 metres (5,740 ft) above sea level. [9] Volcanic ash from Ol Doinyo Lengai influences the surrounding landscape, favoring the growth of nutrient-rich plants. [67] Precipitation falls during two wet seasons in March–May and October–December. [9]

See also

Notes

  1. ↑ Known as hornitos. [13]
  2. ↑ The Naibor Soito monogenetic volcanic field lies between Gelai and Ol Doinyo Lengai. [25]
  3. ↑ Together they make up more than 90% of the cone. [13]
  4. ↑ Carbonatites are magmas that consist of carbonate compounds. [10] At Ol Doinyo Lengai, they are made up of nyererite (Na
    2    Ca(CO
    3    )
    2    ) and gregoryite ((Na
    ,    K
    ,    Ca)
    2    CO
    3    ). [5]
  5. ↑ Silicic lavas mostly issued from the southern crater. [13]
  6. ↑ The volcanic rocks contain up to several percent chlorine and fluorine by weight. [33]
  7. ↑ Eruptions have been recorded in 1880, 1894 (?), 1904, 1913-15, 1917, 1921, 1926, 1940-41, 1954-55, 1958, and 1960. [45]
  8. ↑ 1966 saw explosive eruptions in August and October, which formed a deep crater. [11]
  9. ↑ And have been confused for mud by non-volcanologists. [63]

Related Research Articles

<span class="mw-page-title-main">Volcano</span> Rupture in a planets crust where material escapes

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. The process that forms volcanoes is called volcanism.

<span class="mw-page-title-main">Magma</span> Hot semifluid material found beneath the surface of Earth

Magma is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles.

<span class="mw-page-title-main">Nephelinite</span> Igneous rock made up almost entirely of nepheline and clinopyroxene

Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene. If olivine is present, the rock may be classified as an olivine nephelinite. Nephelinite is dark in color and may resemble basalt in hand specimen. However, basalt consists mostly of clinopyroxene (augite) and calcic plagioclase.

<span class="mw-page-title-main">Carbonatite</span> Igneous rock with more than 50% carbonate minerals

Carbonatite is a type of intrusive or extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals. Carbonatites may be confused with marble and may require geochemical verification.

<span class="mw-page-title-main">East African Rift</span> Active continental rift zone in East Africa

The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. It was formerly considered to be part of a larger Great Rift Valley that extended north to Asia Minor.

<span class="mw-page-title-main">Natrocarbonatite</span> Rare carbonatite lava which erupts from the Ol Doinyo Lengai volcano in Tanzania

Natrocarbonatite is a rare carbonatite lava which erupts from the Ol Doinyo Lengai volcano in Tanzania within the East African Rift of eastern Africa. Natrocarbonatite lavas were first documented in 1962, by J. B. Dawson.

<span class="mw-page-title-main">Lava lake</span> Molten lava contained in a volcanic crater

Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified.

<span class="mw-page-title-main">Nyerereite</span> Very rare sodium calcium carbonate mineral

Nyerereite is a very rare sodium calcium carbonate mineral with formula Na2Ca(CO3)2. It forms colorless, platey pseudohexagonal orthorhombic crystals that are typically twinned. It has a specific gravity of 2.54 and indices of refraction of nα=1.511, nβ=1.533 and nγ=1.535. Nyerereite is not stable in contact with the atmosphere and rapidly breaks down. Collection specimens must be kept in a sealed argon environment.

<span class="mw-page-title-main">Mount Tendürek</span> Shield volcano in eastern Turkey

Mount Tendürek is a shield volcano on the border of Ağrı and Van provinces in eastern Turkey, near the border with Iran. The volcano, which is mostly known for being near the supposed wreck site of Noah's Ark, is very large; its lava flows cover roughly 650 km2 (251 sq mi) across a swath of flat land. The mountain's two main features are the main summit crater Greater Tendürek, and a smaller crater known as Lesser Tendürek which lies to the east of the main crater. The slopes are very gentle and resemble a shield, after which the type is named. Mount Tendürek is known to have erupted viscous lava like that of volcanoes on the island of Hawaii.

<span class="mw-page-title-main">San Pedro (Chile volcano)</span> One of the tallest active volcanoes in the world

San Pedro is a Holocene composite volcano in northern Chile and at 6,155 metres (20,194 ft) in elevation one of the highest active volcanoes in the world. Part of the Chilean Andes' volcanic segment, it is part of the Central Volcanic Zone of the Andes, one of the four tracts of the Andean Volcanic Belt. This region of volcanism includes the world's two highest volcanoes Ojos del Salado and Llullaillaco. San Pedro, like other Andean volcanoes, was formed by the subduction of the Nazca Plate beneath the South America Plate. It has a neighbouring volcano, San Pablo, and is itself formed by two separate edifices usually known as the Old Cone and the Young Cone. These edifices are formed by rocks ranging from basaltic andesite over andesite to dacite and are emplaced on a basement formed by Miocene volcanic rocks.

<span class="mw-page-title-main">Lava</span> Molten rock expelled by a volcano during an eruption

Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from 800 to 1,200 °C. The volcanic rock resulting from subsequent cooling is also often called lava.

<span class="mw-page-title-main">Ol Doinyo Eburru</span> Active complex of volcanoes in Kenya, East Africa

Ol Doinyo Eburru is an active complex of volcanoes in the Great Rift Valley, Kenya to the northwest of Lake Naivasha. It is being exploited for geothermal energy. Soysambu Conservancy is located to the north of the massif, between Lake Elmenteita to the east and Lake Nakuru to the west.

Kunlun Volcanic Group, also known as Ashikule Volcanic Field, is a volcanic field in northwestern Tibet. Eight other volcanic fields are also in the area. The field is within a basin that also contains three lakes.

<span class="mw-page-title-main">Cima volcanic field</span> Volcanic field in San Bernardino County, California

Cima volcanic field is a volcanic field in San Bernardino County, California, close to the border with Nevada. The volcanic field covers a surface area of 600 km2 (230 sq mi) within the Mojave National Preserve west of the Cima Dome and consists of about 40 volcanic cones with about 60 lava flows. The volcanic cones range from simple cones over multi-cratered mountains to eroded hills, and lava flows are up to 9.1 km (5.7 mi) long. At least one lava tube exists in the field and can be visited.

<span class="mw-page-title-main">Sector collapse</span> Collapse of a volcano

A sector collapse or lateral collapse is the structural failure and subsequent collapse of part of a volcano. Unlike a flank collapse, a sector collapse involves the central volcanic pipe. Sector collapses are one of the most hazardous volcanic events, often resulting in lateral blasts, landslides, and changes in volcanic eruptive behavior. Sector collapse can be caused by earthquakes, volcanic eruptions, gradual volcanic deformation, and other processes. Sector collapse events can occur on volcanoes at convergent and divergent plate boundaries. Sector collapses are generally very sudden; however, some attempts have been made to predict collapse events.

<span class="mw-page-title-main">Honolulu Volcanics</span> Volcanic field in Oʻahu, Hawaiʻi

The Honolulu Volcanics are a group of volcanoes which form a volcanic field on the island of Oʻahu, Hawaiʻi, more specifically in that island's southeastern sector and in the city of Honolulu from Pearl Harbor to the Mokapu Peninsula. It is part of the rejuvenated stage of Hawaiian volcanic activity, which occurred after the main stage of volcanic activity that on Oʻahu built the Koʻolau volcano. These volcanoes formed through dominantly explosive eruptions and gave rise to cinder cones, lava flows, tuff cones and volcanic islands. Among these are well known landmarks such as Diamond Head and Punchbowl Crater.

<span class="mw-page-title-main">Lunar Crater volcanic field</span> Volcanic field in Nye County, Nevada

Lunar Crater volcanic field is a volcanic field in Nye County, Nevada. It lies along the Reveille and Pancake Ranges and consists of over 200 vents, mostly small volcanic cones with associated lava flows but also several maars, including one maar named Lunar Crater. Some vents have been eroded so heavily that the structures underneath the volcanoes have been exposed. Lunar Crater itself has been used as a testing ground for Mars rovers and as training ground for astronauts.

<span class="mw-page-title-main">Tocorpuri</span> Volcano in Bolivia and Chile

Tocorpuri is a volcano in Chile, close to the border with Bolivia. Its peak height is most recently given as 5,808 metres (19,055 ft) and it features a 1.3 kilometres (0.81 mi) wide summit crater. The volcano consists mainly of lava flows and pyroclastic deposits and is subdivided into two separate edifices. Just west of Tocorpuri, the La Torta lava dome is a 200 metres (660 ft) high flat-topped structure. The volcanoes are formed by andesitic, dacitic and rhyolitic rocks.

<span class="mw-page-title-main">Kerimasi</span> Volcano in Arusha Region of Tanzania

Kerimasi Volcano, also known as Kerimasi at 2,602 metres (8,537 ft) is an extinct shield volcano located in Monduli District of Arusha Region in Tanzania. The majority of the mountain lies in Engaruka Ward, and a quarter of it is in the Ngorongoro Conservation Area. The volcano is located in the geographic area known as the Crater Highlands and is a shield volcano that last erupted in the Pleistocene.

<span class="mw-page-title-main">Sadiman volcano</span> Volcano in Arusha Region of Tanzania

Saidman volcano, also known as Sadiman or Satiman, is 2,879-meter-high stratovolcano located in Ngorongoro District of Arusha Region in Tanzania. The volcano is located in the geographic area known as the Crater Highlands and is a volcano that last erupted in the Pleistocene. The age of Sadiman volcano is unknown, with one source claiming a Pleistocene age and another claiming a K-Ar age of 4.5 million. Sadiman lava clasts have been discovered in layers dating back 1.7 to 2.0 million years. This volcano is part of the Serengeti-Ngorongoro UNESCO Biosphere Reserve in partnership with the Ngorongoro Conservation Area.

References

  1. 1 2 3 4 5 6 7 GVP 2023, General Information.
  2. ↑ Keller & Krafft 1990, p. 629.
  3. ↑ Bernbaum 2022, p. 183.
  4. ↑ GVP 2023, Synonyms & Subfeatures.
  5. 1 2 3 4 5 6 McFarlane, Lundberg & Belton 2004, p. 98.
  6. ↑ Mangler et al. 2014, p. 43.
  7. 1 2 3 Muthama, Mathu & Kamau 2012, p. 8.
  8. ↑ Zaitsev, Keller & Billström 2009, p. 303.
  9. 1 2 3 4 5 Rey et al. 2021, p. 72.
  10. 1 2 3 4 5 Nyamweru 1988, p. 603.
  11. 1 2 3 Sekisova et al. 2015, p. 1719.
  12. 1 2 3 4 5 Gilbert & Williams-Jones 2008, p. 520.
  13. ↑ Kervyn et al. 2010, p. 921.
  14. 1 2 3 4 5 Mangler et al. 2014, p. 44.
  15. ↑ Klaudius & Keller 2006, p. 174.
  16. 1 2 Delcamp et al. 2015, p. 7.
  17. ↑ Delcamp et al. 2015, p. 8.
  18. ↑ Delcamp et al. 2015, p. 17.
  19. 1 2 3 Mollel & Swisher 2012, p. 274.
  20. 1 2 3 Radebaugh, Barnes & Keith 2020, p. 1.
  21. 1 2 Jones et al. 2019, p. 2517.
  22. ↑ Jones et al. 2019, p. 2522.
  23. ↑ Mollel & Swisher 2012, p. 276.
  24. ↑ Ho & Wauthier 2022.
  25. 1 2 3 4 Oppenheimer 1998, p. 55.
  26. ↑ Klaudius & Keller 2006, p. 173.
  27. ↑ Oppenheimer 1998, p. 60.
  28. ↑ Morogan & Martin 1985, p. 1114.
  29. ↑ Robertson et al. 2014.
  30. ↑ Gilbert & Williams-Jones 2008, p. 524.
  31. ↑ Zaitsev, Keller & Billström 2009, p. 302.
  32. ↑ Mangler et al. 2014, p. 51.
  33. 1 2 3 Hay 1989, p. 80.
  34. ↑ Jones et al. 2019, p. 2518.
  35. ↑ Mangler et al. 2014, p. 48.
  36. ↑ Daud Masungulwa et al. 2021.
  37. 1 2 Biggs et al. 2021, p. 3.
  38. 1 2 3 Fischer et al. 2006.
  39. ↑ Mollel & Swisher 2012, p. 278.
  40. ↑ Klaudius & Keller 2006, p. 176.
  41. ↑ Hay 1989, p. 78.
  42. ↑ Makongoro et al. 2022, p. 209.
  43. ↑ Meshili & Kwon 2020, p. 401.
  44. 1 2 3 Nyamweru 1988, p. 604.
  45. ↑ Nyamweru 1990, p. 389.
  46. ↑ Kervyn et al. 2010, p. 926.
  47. ↑ Nyamweru 1990, p. 387.
  48. ↑ GVP 2023, Deformation history.
  49. ↑ Jones et al. 2019, p. 2525.
  50. ↑ GVP 2023, Eruption history.
  51. ↑ Kervyn et al. 2010, p. 915.
  52. 1 2 Kervyn et al. 2010, p. 914.
  53. ↑ Laxton 2020, p. 438.
  54. ↑ Kervyn et al. 2010, p. 924.
  55. ↑ Muthama, Mathu & Kamau 2012, p. 9.
  56. ↑ Muthama, Mathu & Kamau 2012, p. 15.
  57. ↑ Vye-Brown et al. 2014, p. 4.
  58. 1 2 Vye-Brown et al. 2014, p. 25.
  59. ↑ Vye-Brown et al. 2014, p. 2.
  60. ↑ Biggs et al. 2021, p. 9.
  61. ↑ Kervyn et al. 2010, p. 916.
  62. ↑ Nyamweru 1988, p. 610.
  63. ↑ Dawson et al. 1994, p. 799.
  64. ↑ Rey et al. 2021, p. 79.
  65. 1 2 Dye et al. 2022, p. 30.
  66. ↑ Morrison & Bolger 2014, p. 619.

Sources

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.