Adams Seamount

Adams Seamount
Summit depth 39 m (128 ft)[1]
Height 3,500 m (11,500 ft)
Location
Location Pacific Ocean, SW of Pitcairn Island
Coordinates 25°22′S 129°16′W / 25.367°S 129.267°W / -25.367; -129.267Coordinates: 25°22′S 129°16′W / 25.367°S 129.267°W / -25.367; -129.267
Geology
Last eruption 50 BCE ± 1000 years

Adams Seamount is a submarine volcano above the Pitcairn hotspot in the central Pacific Ocean about 100 kilometres (62 mi) southwest of Pitcairn Island.

Geography and geomorphology

Adams is part of a field of about 90 seamounts 90 kilometres (56 mi) east-southeast away from Pitcairn Island, and the largest of these.[2] Adams lies southeast of another large seamount, Bounty Seamount.[3] Most of these seamounts except for Adams and Bounty are less than 0.5 kilometres (0.31 mi) high.[4] They were discovered in 1989 by the RV Sonne research ship.[5]

It is a conical[6] seamount rising 3,500 metres (11,483 ft) from the sea floor to about 39 metres (128 ft) below the surface of the ocean.[1] The total volume of the seamount, whose "foot" has a diameter of about 30 kilometres (19 mi), is about 858 cubic kilometres (206 cu mi).[7] Adams has two summits,[8] and coral and sand derived from coral has been found on Adams.[4] Given its height, during the last glacial maximum Adams was likely an island.[9]

Its slopes are covered by recent lava flows, volcanic debris and hyaloclastite.[8] Lava flows feature aa lava characteristics and lava tubes, while deeper parts of the edifice are covered with lapilli and scoria.[10] Parasitic vents form cones and mounds on its flanks.[11]

Geology

Adams and the other seamounts were created by the Pitcairn hotspot, and these seamounts are its present-day location.[2] This hotspot is one among several hotspots in the Pacific Ocean, along with the Austral hotspot, Hawaii hotspot, Louisville hotspot, Samoa hotspot and Society hotspot.[5] The seamounts rise from a 30 million years old crust.[12]

Alkali basalt, trachyte[8] and tholeiite have been dredged from Adams Seamount.[13]

Eruption history

The fresh appearance of samples and the lack of sedimentation indicates that Adams Seamount is a recently active seamount.[2] Potassium-argon dating of rocks dredged from Adams Seamount has yielded Holocene ages, including one age of 3,000 ± 1,000 years before present.[12] Other ages range from 4,000 - 7,000 years before present.[14] Unlike Bounty, Adams Seamount displays no active hydrothermal system.[4]

References

  1. 1 2 "Adams Seamount". Global Volcanism Program. Smithsonian Institution. Retrieved 2017-02-28.
  2. 1 2 3 Garapić et al. 2015, p. 2.
  3. ↑ Thießen et al. 2004, p. 418.
  4. 1 2 3 Thießen et al. 2004, p. 409.
  5. 1 2 Hekinian et al. 2003, p. 220.
  6. ↑ Binard, Hékinian & Stoffers 1992, p. 261.
  7. ↑ Hekinian et al. 2003, p. 228.
  8. 1 2 3 Binard, Hékinian & Stoffers 1992, p. 257.
  9. ↑ Neall, Vincent E.; Trewick, Steven A. (27 October 2008). "The age and origin of the Pacific islands: a geological overview". Philosophical Transactions of the Royal Society of London B: Biological Sciences. 363 (1508): 3299. doi:10.1098/rstb.2008.0119. ISSN 0962-8436. PMC 2607379.
  10. ↑ Binard, Hékinian & Stoffers 1992, p. 259.
  11. ↑ Hekinian et al. 2003, p. 229.
  12. 1 2 Guillou, Garcia & Turpin 1997, p. 244.
  13. ↑ Garapić et al. 2015, p. 9.
  14. ↑ Guillou, Garcia & Turpin 1997, p. 247.

Sources

  • Binard, Nicolas; Hékinian, Roger; Stoffers, Peter (June 1992). "Morphostructural study and type of volcanism of submarine volcanoes over the Pitcairn hot spot in the South Pacific". Tectonophysics. 206 (3–4): 245–264. doi:10.1016/0040-1951(92)90379-K. ISSN 0040-1951.
  • Garapić, G.; Jackson, M.G.; Hauri, E.H.; Hart, S.R.; Farley, K.A.; Blusztajn, J.S.; Woodhead, J.D. (July 2015). "A radiogenic isotopic (He-Sr-Nd-Pb-Os) study of lavas from the Pitcairn hotspot: Implications for the origin of EM-1 (enriched mantle 1)". Lithos. 228-229: 1–11. doi:10.1016/j.lithos.2015.04.010. ISSN 0024-4937.
  • Guillou, Hervé; Garcia, Michael O.; Turpin, Laurent (September 1997). "Unspiked K-Ar dating of young volcanic rocks from Loihi and Pitcairn hot spot seamounts". Journal of Volcanology and Geothermal Research. 78 (3–4): 239–249. doi:10.1016/S0377-0273(97)00012-7. ISSN 0377-0273.
  • Hekinian, R; Cheminée, J.L; Dubois, J; Stoffers, P; Scott, S; Guivel, C; Garbe-Schönberg, D; Devey, C; Bourdon, B; Lackschewitz, K; McMurtry, G; Le Drezen, E (March 2003). "The Pitcairn hotspot in the South Pacific: distribution and composition of submarine volcanic sequences". Journal of Volcanology and Geothermal Research. 121 (3–4): 219–245. doi:10.1016/S0377-0273(02)00427-4. ISSN 0377-0273.
  • Thießen, O.; Schmidt, M.; Botz, R.; Schmitt, M.; Stoffers, P. (2004). "Methane Venting into the Water Column Above the Pitcairn and the Society — Austral Seamounts, South Pacific". Oceanic Hotspots. Springer, Berlin, Heidelberg: 407–429. doi:10.1007/978-3-642-18782-7_14.
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