| Revision as of 17:13, 20 December 2019 editVolcanoguy (talk | contribs)Autopatrolled, Extended confirmed users, Pending changes reviewers, Rollbackers106,620 edits →References: add hotspots template← Previous edit | Revision as of 20:44, 29 November 2020 edit undoSphericalSong (talk | contribs)54 editsm Page has been edited to better reflect the current state of the field by slightly rephrasing some of the existing text and adding information about a competing hypothesisTag: RevertedNext edit → | ||
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| The '''St. Helena hotspot''' is a ] |
The '''St. Helena hotspot''' is a ] province located in the southern ]. It is comprised of the island of ] and the ]. It is one of the oldest known hotspots or melting anomalies on Earth, and began to produce ]ic ] about 145 million years ago.<ref>{{cite journal |last1=O’Connor |first1=J.M. |last2=le Roex |first2=A.P. |date=1992 |title=South Atlantic hot spot-plume systems: 1. Distribution of volcanism in time and space |url=https://www.sciencedirect.com/science/article/pii/0012821X9290138L |journal=Earth and Planetary Science Letters |volume=113 |issue=3 |pages=343-364 |doi=10.1016/0012-821X(92)90138-L}}</ref> | ||
| The origins of volcanic activity in the St. Helena Hotspot are disputed. One hypothesis is that it formed as the ] moved east over a stationary ].<ref>{{cite book |last=Wilson |first=M. |editor-last1=Storey |editor-first1=B.C. |editor-last2=Alabaster |editor-first2=T. |editor-last3=Pankhurst |editor-first3=R.J. |title= Magmatism and the Causes of Continental Break-up, Geological Society Special Publication No. 68 |publisher=The Geological Society, London |date=1992 |pages=241-255 |chapter=Magmatism and continental rifting during the opening of the South Atlantic Ocean: A consequence of Lower Cretaceous super-plume activity?}}</ref><ref>{{cite book |last=Condie |first=K.C. |date=2001 |title=Mantle plumes and their record in Earth history |location=Cambridge |publisher=Cambridge University Press |isbn=0 521 80604 6}}</ref> | |||
| Several observations, however, are inconsistent with the plume hypothesis,<ref>{{cite book |last=Foulger |first=G.R. |editor-last1=Foulger |editor-first1=G.R. |editor-last2=Jurdy |editor-first2=D.M. |title=Plates, plumes, and planetary processes: Geological Society of America Special Paper 430 |publisher=The Geological Society of America |date=2007 |pages=1-28 |chapter=The ‘plate’ model for the genesis of melting anomalies |isbn=978-0813724300}}</ref><ref>{{cite book |last=Foulger |first= G.R. |date= 2010|title= Plates vs. plumes: A geological controversy |location= Oxford |publisher=Wiley-Blackwell |isbn=978-1-4443-3679-5}}</ref> and it has been suggested instead that changes in plate motion and consequent changes in stress fields related to plate interactions elsewhere have led to shallow, passive melting along zones of ] weakness.<ref>{{cite web |url=http://www.mantleplumes.org/WebpagePDFs/SAtlantic.pdf |title=Sea-floor spreading and deformation processes in the South Atlantic Ocean: Are hot spots needed? |last1=Fairhead |first1=D.J.|last2=Wilson |first2=M. |date=2004 |website=www.mantleplumes.org/ |access-date=29 November 2020}}</ref><ref>{{cite book |last1=Fairhead |first1=J.D. |last2=Wilson |first2=M. |editor-last1=Foulger |editor-first1=G.R. |editor-last2=Natland |editor-first2=J.H. |editor-last3=Presnall |editor-first3=J.H. |editor-last4=Anderson |editor-first4=D.L. |title=Plates, plumes, and paradigms: Geological Society of America Special Paper 388 |publisher=Geological Society of America |date=2005 |pages=537-553 |chapter=Plate tectonic processes in the South Atlantic Ocean: Do we need deep mantle plumes? |doi=10.1130/2005.2388(32)}}</ref> | |||
| ==References== | ==References== | ||
Revision as of 20:44, 29 November 2020
The St. Helena hotspot is a volcanic province located in the southern Atlantic Ocean. It is comprised of the island of St. Helena and the St. Helena Seamount chain. It is one of the oldest known hotspots or melting anomalies on Earth, and began to produce basaltic lava about 145 million years ago.
The origins of volcanic activity in the St. Helena Hotspot are disputed. One hypothesis is that it formed as the African Plate moved east over a stationary mantle plume.
Several observations, however, are inconsistent with the plume hypothesis, and it has been suggested instead that changes in plate motion and consequent changes in stress fields related to plate interactions elsewhere have led to shallow, passive melting along zones of lithospheric weakness.
References
- O’Connor, J.M.; le Roex, A.P. (1992). "South Atlantic hot spot-plume systems: 1. Distribution of volcanism in time and space". Earth and Planetary Science Letters. 113 (3): 343–364. doi:10.1016/0012-821X(92)90138-L.
- Wilson, M. (1992). "Magmatism and continental rifting during the opening of the South Atlantic Ocean: A consequence of Lower Cretaceous super-plume activity?". In Storey, B.C.; Alabaster, T.; Pankhurst, R.J. (eds.). Magmatism and the Causes of Continental Break-up, Geological Society Special Publication No. 68. The Geological Society, London. pp. 241–255.
- Condie, K.C. (2001). Mantle plumes and their record in Earth history. Cambridge: Cambridge University Press. ISBN 0 521 80604 6.
- Foulger, G.R. (2007). "The 'plate' model for the genesis of melting anomalies". In Foulger, G.R.; Jurdy, D.M. (eds.). Plates, plumes, and planetary processes: Geological Society of America Special Paper 430. The Geological Society of America. pp. 1–28. ISBN 978-0813724300.
- Foulger, G.R. (2010). Plates vs. plumes: A geological controversy. Oxford: Wiley-Blackwell. ISBN 978-1-4443-3679-5.
- Fairhead, D.J.; Wilson, M. (2004). "Sea-floor spreading and deformation processes in the South Atlantic Ocean: Are hot spots needed?" (PDF). www.mantleplumes.org/. Retrieved 29 November 2020.
- Fairhead, J.D.; Wilson, M. (2005). "Plate tectonic processes in the South Atlantic Ocean: Do we need deep mantle plumes?". In Foulger, G.R.; Natland, J.H.; Presnall, J.H.; Anderson, D.L. (eds.). Plates, plumes, and paradigms: Geological Society of America Special Paper 388. Geological Society of America. pp. 537–553. doi:10.1130/2005.2388(32).
16°S 6°W / 16°S 6°W / -16; -6
| Hotspots | |
|---|---|
| Antarctic plate | |
| African plate | |
| Eurasian plate | |
| Indo-Australian plate | |
| Nazca plate | |
| North American plate | |
| Pacific plate | |
| South American plate | |
| Proposed mechanisms: Mantle plume · Plate theory | |
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