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The '''Tasmantid hotspot''' is a [[hotspot (geology)|volcanic hotspot]] located in the [[South Pacific Ocean]]. Due to [[plate tectonics]] the hotspot was under different parts of the [[seabed]] in the past. It was initially centered under what is now the southern [[Coral Sea]] 60 million years ago where the first Tasmantid [[volcano]] was created. As the [[Indo-Australian Plate]] continued to drift northwards the hotspot was positioned in the northern [[Tasman Sea]] 20 million years ago, eventually reaching its current location east of [[Tasmania]] in response to ongoing northward plate motion.<ref name="QK">{{cite book|last=Johnson|first=R. W.|last2=Knutson|first2=J.|last3=Taylor|first3=S. R.|title=Intraplate Volcanism: In Eastern Australia and New Zealand|page=52|publisher=[[Australian Academy of Science]]|year=1989|isbn=0-521-38083-9}}</ref> |
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The '''Tasmantid hotspot''' is a [[volcano|volcanic]] province in the [[South Pacific Ocean]] consisting of a ∼{{Convert|2,500|km|mi|abbr=on}} chain of age-progressive intraplate volcanoes ranging in age from around 56 [[megaannum|Ma]] to around 7 Ma. The volcanic centre of the province was initially in what is now the southern [[Coral Sea]] and moved progressively southward through the [[Tasman Sea]] to its current location east of [[Tasmania]]. It has created a north-south line of [[submarine volcano]]es called the [[Tasmantid Seamount Chain]] which includes over 10 [[seamount]]s, the youngest of which is the 7 million-year-old [[Gascoyne Seamount]].<ref name="QK">{{cite book|last=Johnson|first=R. W.|last2=Knutson|first2=J.|last3=Taylor|first3=S. R.|title=Intraplate Volcanism: In Eastern Australia and New Zealand|page=52|publisher=[[Australian Academy of Science]]|year=1989|isbn=0-521-38083-9}}</ref> |
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The Tasmantid |
The origins of volcanic activity in the area are uncertain. It has been suggested that the province is underlain by a [[mantle plume]] that has remained relatively fixed as the [[Indo-Australian Plate]] has drifted northwards,<ref name="QK"/><ref>{{cite journal |last1=McDougall |first1=I. |last2=Duncan |first2=R.A. |date=1988 |title=Age progressive volcanism in the Tasmantid Seamounts |url=https://www.sciencedirect.com/science/article/pii/0012821X88901732 |journal=Earth and Planetary Science Letters |volume=89 |issue=2 |pages=207-220 |doi=10.1016/0012-821X(88)90173-2}}</ref> and that this plume may initially have created the [[Louisiade Plateau]], a purported [[large igneous province]] at the northern end of the Tasmantid Seamount Chain. <ref>{{cite journal|last=Kalnins|first=L. M.|last2=Cohen|first2=B. E.|last3=Fitton|first3=J. G.|last4=Mark|first4=D. F.|last5=Richards|first5=F. D.|last6=Barfod|first6=D. N.|title=The East Australian, Tasmantid, and Lord Howe Volcanic Chains: Possible mechanisms behind a trio of hotspot trails|journal=AGU Fall Meeting Abstracts|publisher=[[American Geophysical Union]]|year=2015|volume=2015|pages=DI41A–2591|bibcode=2015AGUFMDI41A2591K}}</ref> The Tasmantid plume is thought presently to be {{Convert|400|km|mi|abbr=on}} south of Gascoyne Seamount and is defined by a prominent [[seismic zone|zone of seismic activity]].<ref name="QK"/> |
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The trend and morphology of the seamount chain, however, suggest that its tectonic setting is the main cause of volcanism. The chain is emplaced on an extinct [[Seafloor spreading|spreading centre]] which was active between 84 and 52 Ma, and the seamounts are aligned with deep [[Fault (geology)|faults]] which have channelled [[magma]] along pre-existing zones of [[Lithosphere|lithospheric]] weakness.<ref name=”Richards2018”> {{cite journal |last1=Richards |first1=F.D. |last2=Kalnins |first2=L.M. |last3=Watts |first3=A.B. |last4=Cohen |first4=B.E. |last5=Beaman | first5=R.J. |date=2018 |title=The morphology of the Tasmantid Seamounts: Interactions between tectonic inheritance and magmatic evolution |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GC007821 |journal=Geochemistry, Geophysics, Geosystems |volume=19 |issue=10 |pages=3870-3891|doi=10.1029/2018GC007821}}</ref> Magmas are largely [[Intrusive rock|intrusive]], indicating a weak melting anomaly rather than a Hawaiian-type mantle plume,<ref name=”Richards2018”/> and lithospheric structures and shallow, plate-tectonic processes can account for intraplate volcanism without plume involvement.<ref>{{cite journal |last1=Foulger |first1=G.R. |last2=Natland |first2=J.H. |date=2003 |title=Is "hotspot" volcanism a consequence of plate tectonics? |url=https://science.sciencemag.org/content/300/5621/921|journal=Science |volume=300 |issue=5621 |pages=921-922 |doi= 10.1126/science.1083376}}</ref><ref>{{cite book |last=Foulger |first= Gillian R. |date= 2010|title= Plates vs. plumes: A geological controversy |location= Oxford |publisher=Wiley-Blackwell |isbn=978-1-4443-3679-5}}</ref> The Louisiade Plateau, moreover, is more commonly interpreted as a [[continental fragment]] that detached from the northeast Australian margin during the opening of the Coral Sea than a large igneous province.<ref>{{cite journal |last1=van den Broek |first1=J.M. |last2=Gaina |first2=C. |date=2020 |title=Microcontinents and continental fragments associated with subduction systems |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020TC006063 |journal=Tectonics |volume=39 |issue=2 |pages=e2020TC006063 |doi=10.1029/2020TC006063}}</ref> |
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==References== |
==References== |
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Revision as of 21:32, 30 November 2020
 The Tasmantid hotspot is marked 39 on map | |
| Region | South Pacific Ocean |
|---|---|
| Coordinates | 40°14′S 155°18′E / 40.24°S 155.30°E |
The Tasmantid hotspot is a volcanic province in the South Pacific Ocean consisting of a ∼2,500 km (1,600 mi) chain of age-progressive intraplate volcanoes ranging in age from around 56 Ma to around 7 Ma. The volcanic centre of the province was initially in what is now the southern Coral Sea and moved progressively southward through the Tasman Sea to its current location east of Tasmania. It has created a north-south line of submarine volcanoes called the Tasmantid Seamount Chain which includes over 10 seamounts, the youngest of which is the 7 million-year-old Gascoyne Seamount.[1]
The origins of volcanic activity in the area are uncertain. It has been suggested that the province is underlain by a mantle plume that has remained relatively fixed as the Indo-Australian Plate has drifted northwards,[1][2] and that this plume may initially have created the Louisiade Plateau, a purported large igneous province at the northern end of the Tasmantid Seamount Chain. [3] The Tasmantid plume is thought presently to be 400 km (250 mi) south of Gascoyne Seamount and is defined by a prominent zone of seismic activity.[1]
The trend and morphology of the seamount chain, however, suggest that its tectonic setting is the main cause of volcanism. The chain is emplaced on an extinct spreading centre which was active between 84 and 52 Ma, and the seamounts are aligned with deep faults which have channelled magma along pre-existing zones of lithospheric weakness.[4] Magmas are largely intrusive, indicating a weak melting anomaly rather than a Hawaiian-type mantle plume,[4] and lithospheric structures and shallow, plate-tectonic processes can account for intraplate volcanism without plume involvement.[5][6] The Louisiade Plateau, moreover, is more commonly interpreted as a continental fragment that detached from the northeast Australian margin during the opening of the Coral Sea than a large igneous province.[7]
References
- ^ a b c Johnson, R. W.; Knutson, J.; Taylor, S. R. (1989). Intraplate Volcanism: In Eastern Australia and New Zealand. Australian Academy of Science. p. 52. ISBN 0-521-38083-9.
- ^ McDougall, I.; Duncan, R.A. (1988). "Age progressive volcanism in the Tasmantid Seamounts". Earth and Planetary Science Letters. 89 (2): 207–220. doi:10.1016/0012-821X(88)90173-2.
- ^ Kalnins, L. M.; Cohen, B. E.; Fitton, J. G.; Mark, D. F.; Richards, F. D.; Barfod, D. N. (2015). "The East Australian, Tasmantid, and Lord Howe Volcanic Chains: Possible mechanisms behind a trio of hotspot trails". AGU Fall Meeting Abstracts. 2015. American Geophysical Union: DI41A–2591. Bibcode:2015AGUFMDI41A2591K.
- ^ a b Richards, F.D.; Kalnins, L.M.; Watts, A.B.; Cohen, B.E.; Beaman, R.J. (2018). "The morphology of the Tasmantid Seamounts: Interactions between tectonic inheritance and magmatic evolution". Geochemistry, Geophysics, Geosystems. 19 (10): 3870–3891. doi:10.1029/2018GC007821.
- ^ Foulger, G.R.; Natland, J.H. (2003). "Is "hotspot" volcanism a consequence of plate tectonics?". Science. 300 (5621): 921–922. doi:10.1126/science.1083376.
- ^ Foulger, Gillian R. (2010). Plates vs. plumes: A geological controversy. Oxford: Wiley-Blackwell. ISBN 978-1-4443-3679-5.
- ^ van den Broek, J.M.; Gaina, C. (2020). "Microcontinents and continental fragments associated with subduction systems". Tectonics. 39 (2): e2020TC006063. doi:10.1029/2020TC006063.
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