Are 'hot spots' hot spots?
The term ‘hot spot’ emerged in the 1960s from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently became widely used to refer to volcanic regions considered to be anomalous in the then-new plate tectonic paradigm. It carried with it the im...
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ftunivdurham:oai:dro.dur.ac.uk.OAI2:13308 2023-05-15T16:53:02+02:00 Are 'hot spots' hot spots? Foulger, G.R. 2012-07-01 application/pdf http://dro.dur.ac.uk/13308/ http://dro.dur.ac.uk/13308/1/13308.pdf https://doi.org/10.1016/j.jog.2011.12.003 unknown Elsevier dro:13308 issn:0264-3707 doi:10.1016/j.jog.2011.12.003 http://dro.dur.ac.uk/13308/ http://dx.doi.org/10.1016/j.jog.2011.12.003 http://dro.dur.ac.uk/13308/1/13308.pdf NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Geodynamics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Geodynamics, 58, 2012, 10.1016/j.jog.2011.12.003. Journal of geodynamics, 2012, Vol.58, pp.1-28 [Peer Reviewed Journal] Hotspot Hot spot Plate Plume Temperature Mantle Seismology Petrology Heat flow Article PeerReviewed 2012 ftunivdurham https://doi.org/10.1016/j.jog.2011.12.003 2020-05-28T22:31:14Z The term ‘hot spot’ emerged in the 1960s from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently became widely used to refer to volcanic regions considered to be anomalous in the then-new plate tectonic paradigm. It carried with it the implication that volcanism (a) is emplaced by a single, spatially restricted, mongenetic melt-delivery system, assumed to be a mantle plume, and (b) that the source is unusually hot. This model has tended to be assumed a priori to be correct. Nevertheless, there are many geological ways of testing it, and a great deal of work has recently been done to do so. Two fundamental problems challenge this work. First is the difficulty of deciding a ‘normal’ mantle temperature against which to compare estimates. This is usually taken to be the source temperature of mid-ocean ridge basalts (MORBs). However, Earth's surface conduction layer is ∼200 km thick, and such a norm is not appropriate if the lavas under investigation formed deeper than the 40–50 km source depth of MORB. Second, methods for estimating temperature suffer from ambiguity of interpretation with composition and partial melt, controversy regarding how they should be applied, lack of repeatability between studies using the same data, and insufficient precision to detect the 200–300 °C temperature variations postulated. Available methods include multiple seismological and petrological approaches, modelling bathymetry and topography, and measuring heat flow. Investigations have been carried out in many areas postulated to represent either (hot) plume heads or (hotter) tails. These include sections of the mid-ocean spreading ridge postulated to include ridge-centred plumes, the North Atlantic Igneous Province, Iceland, Hawaii, oceanic plateaus, and high-standing continental areas such as the Hoggar swell. Most volcanic regions that may reasonably be considered anomalous in the simple plate-tectonic paradigm have been built by volcanism distributed throughout hundreds, even thousand of kilometres, and as yet no unequivocal evidence has been produced that any of them have high temperature anomalies compared with average mantle temperature for the same (usually unknown) depth elsewhere. Critical investigation of the genesis processes of ‘anomalous’ volcanic regions would be encouraged if use of the term ‘hot spot’ were discontinued in favour of one that does not assume a postulated origin, but is a description of unequivocal, observed characteristics. Article in Journal/Newspaper Iceland North Atlantic Durham University: Durham Research Online Journal of Geodynamics 58 1 28 |
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Open Polar |
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Durham University: Durham Research Online |
op_collection_id |
ftunivdurham |
language |
unknown |
topic |
Hotspot Hot spot Plate Plume Temperature Mantle Seismology Petrology Heat flow |
spellingShingle |
Hotspot Hot spot Plate Plume Temperature Mantle Seismology Petrology Heat flow Foulger, G.R. Are 'hot spots' hot spots? |
topic_facet |
Hotspot Hot spot Plate Plume Temperature Mantle Seismology Petrology Heat flow |
description |
The term ‘hot spot’ emerged in the 1960s from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently became widely used to refer to volcanic regions considered to be anomalous in the then-new plate tectonic paradigm. It carried with it the implication that volcanism (a) is emplaced by a single, spatially restricted, mongenetic melt-delivery system, assumed to be a mantle plume, and (b) that the source is unusually hot. This model has tended to be assumed a priori to be correct. Nevertheless, there are many geological ways of testing it, and a great deal of work has recently been done to do so. Two fundamental problems challenge this work. First is the difficulty of deciding a ‘normal’ mantle temperature against which to compare estimates. This is usually taken to be the source temperature of mid-ocean ridge basalts (MORBs). However, Earth's surface conduction layer is ∼200 km thick, and such a norm is not appropriate if the lavas under investigation formed deeper than the 40–50 km source depth of MORB. Second, methods for estimating temperature suffer from ambiguity of interpretation with composition and partial melt, controversy regarding how they should be applied, lack of repeatability between studies using the same data, and insufficient precision to detect the 200–300 °C temperature variations postulated. Available methods include multiple seismological and petrological approaches, modelling bathymetry and topography, and measuring heat flow. Investigations have been carried out in many areas postulated to represent either (hot) plume heads or (hotter) tails. These include sections of the mid-ocean spreading ridge postulated to include ridge-centred plumes, the North Atlantic Igneous Province, Iceland, Hawaii, oceanic plateaus, and high-standing continental areas such as the Hoggar swell. Most volcanic regions that may reasonably be considered anomalous in the simple plate-tectonic paradigm have been built by volcanism distributed throughout hundreds, even thousand of kilometres, and as yet no unequivocal evidence has been produced that any of them have high temperature anomalies compared with average mantle temperature for the same (usually unknown) depth elsewhere. Critical investigation of the genesis processes of ‘anomalous’ volcanic regions would be encouraged if use of the term ‘hot spot’ were discontinued in favour of one that does not assume a postulated origin, but is a description of unequivocal, observed characteristics. |
format |
Article in Journal/Newspaper |
author |
Foulger, G.R. |
author_facet |
Foulger, G.R. |
author_sort |
Foulger, G.R. |
title |
Are 'hot spots' hot spots? |
title_short |
Are 'hot spots' hot spots? |
title_full |
Are 'hot spots' hot spots? |
title_fullStr |
Are 'hot spots' hot spots? |
title_full_unstemmed |
Are 'hot spots' hot spots? |
title_sort |
are 'hot spots' hot spots? |
publisher |
Elsevier |
publishDate |
2012 |
url |
http://dro.dur.ac.uk/13308/ http://dro.dur.ac.uk/13308/1/13308.pdf https://doi.org/10.1016/j.jog.2011.12.003 |
genre |
Iceland North Atlantic |
genre_facet |
Iceland North Atlantic |
op_source |
Journal of geodynamics, 2012, Vol.58, pp.1-28 [Peer Reviewed Journal] |
op_relation |
dro:13308 issn:0264-3707 doi:10.1016/j.jog.2011.12.003 http://dro.dur.ac.uk/13308/ http://dx.doi.org/10.1016/j.jog.2011.12.003 http://dro.dur.ac.uk/13308/1/13308.pdf |
op_rights |
NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Geodynamics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Geodynamics, 58, 2012, 10.1016/j.jog.2011.12.003. |
op_doi |
https://doi.org/10.1016/j.jog.2011.12.003 |
container_title |
Journal of Geodynamics |
container_volume |
58 |
container_start_page |
1 |
op_container_end_page |
28 |
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1766043563372576768 |