{{Coord|||type:landmark|format=dms|name=Azores hotspot|qid=Q18415078|display=title}}{{Short description|Volcanic hotspot at the Azores}}
thumb|right|350px|The Azores hotspot is marked 1 on map
The '''Azores hotspot''' is a volcanic hotspot in the Northern Atlantic Ocean. The Azores is relatively young and is associated with a bathymetric swell, a gravity anomaly and ocean island basalt geochemistry.<ref name="Gente et al">{{cite journal|url=http://www.kharsag.net/images/download/GenteG3_03.pdf |title=Interaction between the Mid-Atlantic Ridge and the Azores hot spot during the last 85 Myr: Emplacement and rifting of the hot spot-derived plateaus |author1=Gente P. |author2=Dyment J. |author3=Maia M. |author4=Goslin J. |journal=Geochemistry, Geophysics, Geosystems |year=2003 |volume=4 |issue=10 |pages=1–23 |doi=10.1029/2003GC000527 |url-status=dead |archiveurl=https://web.archive.org/web/20131220044834/http://www.kharsag.net/images/download/GenteG3_03.pdf |archivedate=2013-12-20 |bibcode=2003GGG.....4.8514G|s2cid=56297775 }}</ref> The Azores hotspot lies just east of the Mid-Atlantic Ridge<ref name="Cannat et al.">{{cite journal|url=http://www.ipgp.fr/rech/lgm/je/PDF/1999CannatetalEPSL.pdf |title=Mid-Atlantic Ridge–Azores hotspot interactions: along-axis migration of a hotspot-derived event of enhanced magmatism 10 to 4 Ma ago |author=Cannat, M. |author-link1=Mathilde Cannat|author2=Briais, A. |author3=Deplus, C. |author4=Escartin, J. |author5=Georgen, J. |author6=Lin, J. |author7=Mercouriev, S. |author8=Meyzen, C. |author9=Muller, M. |author10=Pouliquen, G. |author11=Rabain, A. |author12=da Silva, P. |name-list-style=amp |journal=Earth and Planetary Science Letters |year=1999 |volume=173 |issue=3 |pages=257–269 |doi=10.1016/S0012-821X(99)00234-4 |url-status=dead |archiveurl=https://web.archive.org/web/20131220044834/http://www.ipgp.fr/rech/lgm/je/PDF/1999CannatetalEPSL.pdf |archivedate=2013-12-20 |bibcode=1999E&PSL.173..257C}}</ref>
==Geological area== The Azores domain comprises the Azores Plateau and the Azores archipelago (formed of 9 islands extending a distance of {{convert|480|km|mi|abbr=off}} which have been volcanically active for around 7 million years). <!-- Previous phrasing left it unclear if just the islands had been volcanic, or the whole domain.--> The archipelago lies on the lateral branch of the Mid-Atlantic Ridge near the junction of three major tectonic plates; the North American Plate, the Eurasian Plate and the African Plate.<ref name="Silveira et al.">{{cite journal | url=https://www.researchgate.net/publication/222700910 | title=Azores hotspot signature in the upper mantle | author=Silveria, G. | author2=Stutzmann, E. | author3=Davaille, A.|author3-link=Anne Davaille | author4=Montagner, J. | author5=Mendes-Victor, L. | author6=Sebai, A. | name-list-style=amp | journal=Journal of Volcanology and Geothermal Research | year=2006 | volume=156 | issue=1–2 | pages=23–34 | doi=10.1016/j.jvolgeores.2006.03.022| bibcode=2006JVGR..156...23S }}</ref> This unique location causes the area to have ridge-hotspot interaction with a variation of volcanic processes.
==The Azores Plateau==
The Azores archipelago rises from Azores Plateau, which is an area of thickened oceanic crust thought to have formed over the last 20 million years. Negative velocity S-wave anomalies have been mapped beneath the Azores in the upper {{convert|250|–|300|km|mi|abbr=off}}. This has been suggested to be a signature of a plume that created the Azores Plateau.<ref name="Silveira et al."/> Another theory is that the excess volcanism simply results from excess extension at this unusual triple junction.<ref>{{cite journal|last=Smith|first=A. G.|date=2007|title=A plate model for Jurassic to recent intraplate volcanism in the Pacific Ocean basin|journal=In Plates, Plumes, and Planetary Processes, Edited by G.R. Foulger and D.M. Jurdy, Geological Society of America Special Paper 530, Boulder, CO|volume=430|pages=471–496}}</ref>
==Hotspot–ridge relationships==
The Mid-Atlantic Ridge is a zone of extension that permits magma to rise, forming dikes and surface volcanism. Areas of excess magmatism on the Mid-Atlantic Ridge have been called hotspots e.g. the Azores. Gravity field modelling studies have shown that the crustal thickness in this area is 60% greater than normal and the spreading ridge is elevated.<ref name="Bourdon et al.">{{cite journal | url=https://www.researchgate.net/publication/222493962 | title=Ridge-hotspot interaction along the Mid-Atlantic Ridge between 37°30′ and 40°30′N: the UTh disequilibrium evidence | author=Bourdon, B. | author2=Langmuir, C. H. | author3=Zinder, A. | name-list-style=amp | journal=Earth and Planetary Science Letters | year=1996 | volume=142 | issue=1–2 | pages=175–189 | doi=10.1016/0012-821x(96)00092-1 | bibcode=1996E&PSL.142..175B| doi-access=free }}</ref> The hotspot is asymmetrical (north and south). It is thought that crust at ridges is formed by a combination of processes (magmatic and tectonic) with magma addition coming from short lived magma chambers.<ref name="Singh et al.">{{cite journal|url=http://lib.gig.ac.cn/local/nature/442,1029-1032.pdf |title=Discovery of a magma chamber and faults beneath a Mid-Atlantic Ridge hydrothermal field |author=Singh, S. C. |author2=Crawford, W. C. |author3=Carton, H. |author4=Seher, T. |author5=Combier, V. |author6=Cannat, M.|author-link6=Mathilde Cannat |author7=Canales, J. P. |author8=Dusunur, D. |author9=Escartin, J. |author10=Miranda, M. |name-list-style=amp |journal=Nature |year=2006 |volume=442 |issue=7106 |pages=1029–1032 |doi=10.1038/nature05105 |url-status=dead |archiveurl=https://web.archive.org/web/20131220080930/http://lib.gig.ac.cn/local/nature/442%2C1029-1032.pdf |archivedate=2013-12-20 |pmid=16943836 |bibcode=2006Natur.442.1029S |s2cid=4301009 }}</ref> The increased melt production within the mantle may have supported a longer lived magma chamber causing the crust to be thicker. However, the Mid-Atlantic Ridge has also been shown to have affected the characteristics of the Azores Plateau. It has been suggested that the main volcanic ridges on the plateau were created at the Mid-Atlantic Ridge spreading axis.
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==References== {{reflist}}
==External links== *[http://adsabs.harvard.edu/abs/2003AGUFM.T41C0226S Azores Hotspot Deep Signature] *[https://web.archive.org/web/20160303201427/http://seismolab.gso.uri.edu/pub/Yang.T.EPSL.2006.pdf Upper mantle structure beneath the Azores hotspot from finite-frequency seismic tomography]
{{Hotspots}}
Category:Hotspots of the Atlantic Ocean Category:Geology of the Azores