Editing Geography of Samoa (section)

== Tectonics ==
The Samoan archipelago has many features that are consistent with a plume-driven [[Hotspot_(geology)|hotspot]] model, including the currently active submarine volcano [[Vailuluʻu]] that anchors the eastern extremity. However, the chain's proximity to the northern end of the [[Tonga trench]], and the presence of voluminous young volcanism on what should be the oldest (~5 my) western island [[Savaiʻi]] has induced controversy regarding a simple plume/hotspot model.<ref name="HartCoetzee">{{cite web|url=https://www.researchgate.net/publication/222556459|last1=Hart|first1=S.R.|last2=Coetzee|first2=M|last3=Workman|first3=R|last4=Blusztajn|first4= Jerzy|title=Genesis of the Western Samoa seamount province: Age, geochemical fingerprint and tectonics|publisher=Earth and Planetary Science Letters|year=2004|page=38}}</ref> The Samoan archipelago was most likely created by the [[Pacific Plate|Pacific Tectonic Plate]] traveling over a [[Hotspot_(geology)|fixed hotspot]]. The [[Samoa hotspot]] trail is in part coincident with a large group of islands and seamounts {{convert|1700|km|0|abbr=on}} long, which were probably formed by the same hotspot, but also intersect with older seamounts along the [[hotspot highway]] left by the [[Macdonald hotspot|Macdonald]], [[Arago hotspot|Rurutu]], and [[Rarotonga hotspot|Rarotonga]] hotspots and feature substantial [[Post shield stage|postshield]] volcanism, probably owing to tectonic phenomena triggered by the subduction of the Pacific Plate under the [[Australian Plate]] at the nearby [[Tonga Trench]].<ref name="PriceJackson2017">{{cite journal |last1=Price |first1=Allison A. |last2=Jackson |first2=Matthew G. |last3=Blichert-Toft |first3=Janne |author3-link=Janne Blichert-Toft |last4=Kurz |first4=Mark D. |last5=Gill |first5=Jim |last6=Blusztajn |first6=Jerzy |last7=Jenner |first7=Frances |last8=Brens |first8=Raul |last9=Arculus |first9=Richard |title=Geodynamic implications for zonal and meridional isotopic patterns across the northern Lau and North Fiji Basins |journal=Geochemistry, Geophysics, Geosystems |date=March 2017 |volume=18 |issue=3 |doi=10.1002/2016gc006651 |page=23 |language=en |issn=1525-2027|bibcode=2017GGG....18.1013P |hdl=1912/8979 |url=https://darchive.mblwhoilibrary.org/bitstream/1912/8979/1/Price_et_al-2017-Geochemistry%2c_Geophysics%2c_Geosystems.pdf |doi-access=free }}</ref><ref name="Smith-Vaniz1987">{{cite journal |last1=Smith-Vaniz |first1=William F. |title=The Saber-Toothed Blennies, Tribe Nemophini (Pisces: Blenniidae): An Update |journal=Proceedings of the Academy of Natural Sciences of Philadelphia |date=1987 |volume=139 |issue=1 |page=5 |jstor=4064893 }}</ref><ref name=sch>{{cite web|url=http://serc.carleton.edu/sp/erese/samoan-hotspot.html|work=Enduring Resources Earth Science Education|title=Hotspot Lesson: Samoan Hotspot|first=Jamie A.|last=Russell|access-date=2 December 2009}}</ref><ref>{{cite web |url=http://oceandots.com/pacific/bankx/ |title=Samoan Hotspot Trail |access-date=2009-12-01 |url-status=usurped |archive-url=https://web.archive.org/web/20101223043232/http://oceandots.com/pacific/bankx/ |archive-date=December 23, 2010 }}</ref><ref>{{Harvnb|Bird|2003|loc=Tonga Plate (TO), Kermadec Plate (KE), and Niuafo’ou Plate (NI), p. 28}}</ref>

[[Vailuluʻu]] is a [[volcano|volcanic]] [[seamount]] discovered in 1975. It rises from the sea floor to a depth of {{convert|593|m|ft|abbr=on}} and is located between [[Tau, American Samoa|Ta{{okina}}u]] and [[Rose Atoll|Rose]] islands at the eastern end of the [[Samoa hotspot]] chain. The [[basalt|basaltic]] seamount is considered to mark the current location of the Samoa hotspot. The summit of Vailulu{{okina}}u contains a {{convert|2000|m|ft|abbr=on}} wide, {{convert|400|m|ft|abbr=on}} deep oval-shaped [[caldera]]. Two principal rift zones extend east and west from the summit, parallel to the trend of the Samoan hotspot. A third less prominent rift extends southeast of the summit.<ref name="HartCoetzee" />

[[Rose Atoll]] and [[Malulu seamount]] are likely remnants of where the path of either the [[Macdonald hotspot|Macdonald]] or [[Rarotonga hotspot|Rarotonga]] hotspots crossed the path of the [[Samoa hotspot]].<ref name="JacksonHart2010">{{cite journal|last1=Jackson|first1=Matthew G.|last2=Hart|first2=Stanley R.|last3=Konter|first3=Jasper G.|last4=Koppers|first4=Anthony A. P.|last5=Staudigel|first5=Hubert|last6=Kurz|first6=Mark D.|last7=Blusztajn|first7=Jerzy|last8=Sinton|first8=John M.|title=Samoan hot spot track on a "hot spot highway": Implications for mantle plumes and a deep Samoan mantle source|journal=Geochemistry, Geophysics, Geosystems|date=December 2010|volume=11|issue=12|page=19|doi=10.1029/2010GC003232|bibcode=2010GGG....1112009J|s2cid=131425199 }}</ref><ref name="Koppers2011">{{cite journal |last1=Koppers |first1=Anthony A. P. |last2=Russell |first2=Jamie A. |last3=Roberts |first3=Jed |last4=Jackson |first4=Matthew G. |last5=Konter |first5=Jasper G. |last6=Wright |first6=Dawn J. |last7=Staudigel |first7=Hubert |last8=Hart |first8=Stanley R. |title=Age systematics of two young en echelon Samoan volcanic trails |journal=Geochemistry, Geophysics, Geosystems |date=July 2011 |volume=12 |issue=7 |page=5 |doi=10.1029/2010GC003438|hdl=1912/4769 |hdl-access=free |bibcode=2011GGG....12.7025K |s2cid=54947952 }}</ref><ref>{{cite journal |last1=Price |first1=Allison A. |last2=Jackson |first2=Matthew G. |last3=Blichert-Toft |first3=Janne |last4=Blusztajn |first4=Jerzy |last5=Conatser |first5=Christopher S. |last6=Konter |first6=Jasper G. |last7=Koppers |first7=Anthony A.P. |last8=Kurz |first8=Mark D. |title=Geochemical evidence in the northeast Lau Basin for subduction of the Cook-Austral volcanic chain in the Tonga Trench |journal=Geochemistry, Geophysics, Geosystems |date=May 2016 |volume=17 |issue=5 |pages=1694–1724 |doi=10.1002/2015GC006237|bibcode=2016GGG....17.1694P |hdl=1912/8238 |doi-access=free |hdl-access=free }}</ref> Some seamounts in western [[Samoa]] ("Samoan Seamounts"<ref name="Koppers2013">{{Cite journal|last1=Koppers|first1=A. A.|last2=Konter|first2=J. G.|last3=Jackson|first3=M. G.|date=2013-12-01|title=Insights Into the Origin of the Longest-lived Hotspot in the Pacific: Clues from the Tuvalus|journal=AGU Fall Meeting Abstracts|volume=13|pages=V13F–2668|bibcode=2013AGUFM.V13F2668K}}</ref>), which were emplaced together with Tuvalu between 63 and 42 million years ago are likely remnants of the [[Arago hotspot|Rurutu hotspot]].<ref name="Finlayson2016a">{{Cite journal|last1=Finlayson|first1=V.|last2=Konter|first2=J. G.|last3=Konrad|first3=K.|last4=Price|first4=A. A.|last5=Koppers|first5=A. A. P.|last6=Jackson|first6=M. G.|date=2016-12-01|title=Identification of a Hawaiian-Emperor Style Bend in the Tuvalu Segment of the Rurutu Hotspot|journal=AGU Fall Meeting Abstracts|volume=52|pages=DI52A–05|bibcode=2016AGUFMDI52A..05F}}</ref>  These are also known as the "interloper seamounts".<ref name="Finlayson2016">{{Cite journal|last1=Finlayson|first1=V.|last2=Konter|first2=J. G.|last3=Konrad|first3=K.|last4=Koppers|first4=A.A.P.|last5=Jackson|first5=M.G.|last6=Rooney|first6=T.O.|date=October 2018|title=Sr–Pb–Nd–Hf isotopes and 40Ar/39Ar ages reveal a Hawaii–Emperor-style bend in the Rurutu hotspot".|journal=Earth and Planetary Science Letters|volume=500|pages=168–179|bibcode=2018E&PSL.500..168F|doi=10.1016/j.epsl.2018.08.020|s2cid=135064417|issn=0012-821X|doi-access=free}}</ref> Other undated seamounts in Samoa have been linked to the Rurutu hotspot on the basis of geochemical evidence.<ref>{{Cite journal|last1=Jackson|first1=Matthew G.|last2=Konter|first2=Jasper G.|last3=Steinberger|first3=Bernhard|last4=Koppers|first4=Anthony A. P.|last5=Konrad|first5=Kevin|date=2018-02-27|title=On the relative motions of long-lived Pacific mantle plumes|journal=Nature Communications|volume=9|issue=1|page=854|bibcode=2018NatCo...9..854K|doi=10.1038/s41467-018-03277-x|issn=2041-1723|pmc=5829163|pmid=29487287}}</ref>