List of seamounts in the Marshall Islands
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The Marshall Islands are the site of a number of seamounts. These volcanoes form several groups, including the Ralik Chain, the Ratak Chain and some seamounts around Anewetak.[1] These seamounts are in turn part of a larger province that extends from the South Pacific to the Mariana Trench and is characterized by unusually shallow ocean ground.[2]
These seamounts and volcanoes do not have simple hotspot-like age progressions, with some volcanoes being younger than one would expect from age progression and having more than one active episode. In some places, a middle Cretaceous and a late Cretaceous episode of volcanic activity have been determined by radiometric dating. Despite this, some hotspot-based genesis models have been formulated, often implying that French Polynesian hotspots are responsible for the formation of seamounts,[1] with the Society hotspot, Rurutu hotspot, Rarotonga hotspot and the Macdonald hotspot being candidate hotspots responsible for the development of the Marshall Islands seamounts.[3] Such linkages are in part supported by geochemical data.[4] Some discrepancies between the age and position of such seamounts and the predictions of the hotspot model may reflect the activity of short-lived hotspots linked to large mantle plumes that produce more than one hotspot.[5]
| Name | Other names | Etymology | Coordinates | Depth below sea level | Age | Volume | Details |
|---|---|---|---|---|---|---|---|
| Aean̄-Kaņ[6] | Marovoiy[7] | A taboo fishing spot at Eniwetok[8] | 14°52.98′N 160°27.38′E / 14.88300°N 160.45633°E[9] | 850 metres (2,790 ft)[9] | Mid-Cretaceous[10] | 10,389 cubic kilometres (2,492 cu mi).[9] | Since the Eocene manganese nodules developed on the seamount,[11] which may have been created by the Macdonald hotspot.[10] |
| Neen-Koiaak[6] | According to legend, the fastest runner in the Marshall Islands[8] | 14°22.62′N 161°01.16′E / 14.37700°N 161.01933°E[12] | 1,025 metres (3,363 ft)[12] | 102 million years[12] | 7,083 cubic kilometres (1,699 cu mi)[12] | Samples dredged from Neen-Koiaak include hawaiite[13] containing clinopyroxene, olivine and plagioclase.[14] | |
| Wōd-Eņ Rok[6] | South-Wod-En[15] | A coral head[16] | 15°13.20′N 163°00.00′E / 15.22000°N 163.00000°E[15] | 76 million years[15] | While its position makes it a candidate member of the Ralik hotspot trail, it appears to be too old.[17] There is some geochemical similarity to the Rurutu hotspot.[4] | ||
| Wōd-Eņ Iōn̄[6] | North-Wod-En,[18] Nazimova[7] | A coral head[16] | 16°06.00′N 163°02.40′E / 16.10000°N 163.04000°E[18] | 86 million years[18] | While its position makes it a candidate member of the Ralik hotspot trail, it appears to be too old.[17] There is some geochemical similarity to the Rurutu hotspot.[4] | ||
| Ļewa[6] | A person who received canoe building knowledge, one of the first two[16] | 14°01.80′N 163°07.80′E / 14.03000°N 163.13000°E[19] | 100 million years[19] | Part of the Ralik Chain,[20] Albian-age fossils have been dredged from this seamount.[21] | |||
| Ļōbbadede[6] | Lobhadode[22] | A chief from Bikini[16] | 13°52.80′N 163°51.60′E / 13.88000°N 163.86000°E[22] | 94 million years[22] | Depending on the plate reconstruction model chosen, Lobbadede appears to coincide with the location of the Macdonald hotspot.[10] Limestone and fossils of Campanian-Cenomanian age have been found on Lobbadede,[3] which appears to have had a second volcanic episode in the Cretaceous.[20] | ||
| Wōden-Kōpakut[6] | Ratak[23] | A coral head[16] | 13°56.40′N 167°28.80′E / 13.94000°N 167.48000°E[23] | 1,320 metres (4,330 ft)[24] | 85 million years[23] or 82.2 ± 1.6 million years[25] | Part of the Ratak Chain with Limalok,[20] it was also active during the late Cretaceous[21] and has a well developed summit platform.[26] One reconstruction of plate motion places Woden-Kopakut close to the Rurutu hotspot.[1] Hawaiite has been dredged from the seamount and contains iron oxides, plagioclase and zeolites.[27] | |
| Radik[6] | A chief on Ujlan[8] | ||||||
| Ļainjin[6] | A legendary navigator[8] | 11°09.00′N 161°03.00′E / 11.15000°N 161.05000°E[28] | |||||
| Ļōjemeja[6] | A chief in Ujlan[8] | 11°26.40′N 161°05.40′E / 11.44000°N 161.09000°E[29] | 1,750 metres (5,740 ft)[30] | Steep upper flanks, and a volcanic pinnacle is found between the summit and a sediment-covered terrace.[30] | |||
| Ļami[6] | According to legend an Eniwetok giant[8] | 11°54.60′N 161°24.60′E / 11.91000°N 161.41000°E[31] | 1,295 metres (4,249 ft)[30] | 86 million years[31] | Slumps and terraces, terraces that appear to be congruent with these on Lomilik, surround this seamount. Its summit plateau is covered by sediments, sediment-filled basins and volcanic knolls.[30] | ||
| Peto-Eņ[6] | A taboo channel at Eniwetok[8] | 12°22.80′N 161°19.20′E / 12.38000°N 161.32000°E[32] | |||||
| Lomilik[6] | A place at Eniwetok with good fishing opportunities[8] | 11°42′N 161°37′E / 11.700°N 161.617°E[33] | The summit has volcanic knobs and sediment-filled basins in between. The north flank has a terrace and the rest of the slopes is covered with slumps, talus and sediments.[30] | ||||
| Litōrmālu[6] | A legendary navigator[8] | 10°53.40′N 161°27.60′E / 10.89000°N 161.46000°E[34] | |||||
| Ļo-Wūliej[6] | A cape at Eniwetok[8] | 12°09.60′N 162°15.60′E / 12.16000°N 162.26000°E[35] | |||||
| North Ļāānṃōjānjān[6] | Reference to shipbuilding techniques[16] | 13°07.80′N 162°47.20′E / 13.13000°N 162.78667°E[36] | 1,090 metres (3,580 ft)[30] | Has a rugged appearance with little sediment.[37] It also features several terraces and two large slumps.[30] | |||
| South Ļāānṃōjānjān[6] | Reference to shipbuilding techniques[16] | 12°41.56′N 162°37.17′E / 12.69267°N 162.61950°E[38] | 1,395 metres (4,577 ft)[38] | 1,611 cubic kilometres (386 cu mi)[38] | Has a rugged appearance with little sediment.[37] | ||
| Bwewa Kaņ[6] | Named after canoe keels[16] | 13°33.60′N 164°25.20′E / 13.56000°N 164.42000°E[39] | 88 million years[39] | Part of the Ralik Chain, may have been formed by a hotspot together with a stage of Wodejebato.[17] | |||
| Lōjabōn-Bar[6] | A strong traditional personage at Bikini[16] | 13°09.00′N 164°30.00′E / 13.15000°N 164.50000°E[40] | |||||
| Wōdejebato[6] | Sylvania[41] | Bikini's most feared sea god[16] | 11°55.95′N 164°51.72′E / 11.93250°N 164.86200°E[41] | 1,290 metres (4,230 ft)[41] | 82 million years[41] | 12,476 cubic kilometres (2,993 cu mi)[41] | |
| Look[6] | 12°12.00′N 166°13.80′E / 12.20000°N 166.23000°E[42] | 999 metres (3,278 ft)[37] | 140 million years[42] Look is the oldest known seamount.[43] | Flat-topped seamount that can be considered a guyot[44] and is located between the Ratak Chain and the Ralik Chain,[45] and fairly old. Its geochemistry is intermediate between these two chains as well, which may indicate that volcanism was strongly influenced by the crust.[46] Look Seamount is dotted by volcanic cones and has a rilled appearance[47] as well as slumps; the summit is covered by sediment that mostly buries small volcanic pinnacles and sediment-filled depressions.[37] | |||
| Ruwitūn̄tūn̄[6] | 11°49.80′N 167°00.00′E / 11.83000°N 167.00000°E[48] | 1,215 metres (3,986 ft)[37] | 66 million years[48] | Flat-topped seamount that can be considered a guyot;[44] basins and volcanic knolls dot its summit platform and some pinnacles contain craters.[37] Fossils indicate that Ruwituntun developed either during or before the Albian.[21] | |||
| Ļāwūn-Pikaar[6] | Bikar[49] | Legendary chief in Pikaar[16] | 12°09.60′N 168°51.60′E / 12.16000°N 168.86000°E[50] | Ankaramite-like rock containing clinopyroxene and degradation products of olivine and mellilite has been dredged[27] | |||
| Ļōkōto-N̄ōrn̄ōr[6] | 13°06.00′N 169°26.40′E / 13.10000°N 169.44000°E[51] | ||||||
| Jebo[6] | 11°03.00′N 170°39.60′E / 11.05000°N 170.66000°E[52] | ||||||
| Pali[6] | Name given by the government of Micronesia.[53] | Probably Cretaceous[54] | The seamount is surrounded by a sediment cover and might feature slumps. Hyaloclastite and phosphorite have been dredged from it.[55] | ||||
| Likelep[6] | A site on Ujlan[8] | 10°36.00′N 160°28.80′E / 10.60000°N 160.48000°E[56] | 1,545 metres (5,069 ft)[57] | 82 million years[56] | Biotite, hornblende and plagioclase have been dredged from Likelep, and the seamount is of Campanian age. Likelep may be part of a seamount trail[58] and is part of the Ujlān volcanic complex.[59] A sediment cap and volcanic structures are found on its top, with a volcanic cone protruding through the sediment. Slumps occur on its flanks and a seamount farther north is connected to Likelep.[57] | ||
| Lalibjet[6] | A sea god[8] | 10°08.40′N 159°55.20′E / 10.14000°N 159.92000°E[60] | 1,439 metres (4,721 ft)[61] | 74 million years[60] | May have been produced by the Rarotonga hotspot together with Eniwetok[62] and is part of the Ujlān volcanic complex.[59] Part of the sediment cap on its summit appears to have been removed by a slump.[57] | ||
| Ujlān[6] | Ujelang[63] | 9°46.80′N 160°25.20′E / 9.78000°N 160.42000°E[63] | 1,250 metres (4,100 ft)[57] | 80 million years[63] | Seamount with three separate summits.[47] Ujlan may be part of a seamount trail[58] and is part of the Ujlān volcanic complex.[59] The southwestern flank has a terrace.[57] | ||
| Ļōtab[6] | A descendant of Litōrmālu[8] | 10°13.80′N 160°43.20′E / 10.23000°N 160.72000°E[64] | 1,557 metres (5,108 ft)[61] | 80 million years[64] | Lotab may be part of a seamount trail[58] and is part of the Ujlān volcanic complex;[59] it also features traces of mass failures[57] and on the northeastern flank it is connected to another seamount.[61] | ||
| Ļajutōkwa[6] | A navigator[8] | 10°28.80′N 160°46.80′E / 10.48000°N 160.78000°E[65] | 1,585 metres (5,200 ft)[30] | 81 million years[65] | Lajutokwa may be part of a seamount trail[58] and is part of the Ujlān volcanic complex.[59] | ||
| Lo-En[6] | Hess[66] | Named after the hibiscus tree[8] | 10°06.00′N 162°52.20′E / 10.10000°N 162.87000°E[66] | 113 million years[66] | |||
| Mij-Lep[6] | A gap between islands on Ujlan[8] | 8°48.60′N 163°12.60′E / 8.81000°N 163.21000°E[67] | 1,105 metres (3,625 ft)[61] | 106 million years[67] | A number of pinnacles, including a flat topped one on the summit, cover Mij-Lep.[61] | ||
| Ļemkein[6] | 9°18′N 166°05′E / 9.300°N 166.083°E[33] | ||||||
| Ļewōnjoui[6] | 10°32.31′N 166°27.83′E / 10.53850°N 166.46383°E[68] | 2,985 metres (9,793 ft)[68] | 1,441 cubic kilometres (346 cu mi)[68] | ||||
| Ļōkkwōrkwōr[6] | Erikub[69] | 9°09.00′N 170°00.00′E / 9.15000°N 170.00000°E[69] | 1,400 metres (4,600 ft)[26] | 87 million years[69] | Alkali basalts and hawaiite have been dredged, which contain clinopyroxene, olivine derivatives and plagioclase and show evidence of having been eroded above the water surface[27] | ||
| Litakpooki[6] | 8°18.60′N 160°38.40′E / 8.31000°N 160.64000°E[70] | ||||||
| Ṃaanjidep[6] | A chief from Jalwoj[16] | 6°43.80′N 169°19.80′E / 6.73000°N 169.33000°E[71] | 2,215 metres (7,267 ft)[61] | The depth probably does not refer to the actual summit.[61] | |||
| Ļoṃjenaelik[6] | A chief from Arno[16] | ||||||
| Ļōmōļkā[6] | A chief from Mile[16] | 6°37.80′N 172°21.60′E / 6.63000°N 172.36000°E[72] | |||||
| Limalok[6] | Harrie[73] | A chiefess from Mile[16] | 5°36.00′N 172°21.60′E / 5.60000°N 172.36000°E[73] | 68 million years[73] |