Aegir Ridge
TheAegir Ridgeis an extinct segment of theMid-Atlantic Ridgein the far-northernAtlantic Ocean.It marks the initial break-up boundary betweenGreenlandandNorway,along which seafloor spreading was initiated at the beginning of theEoceneepochto form the northern Atlantic Ocean. Towards the end of the Eocene, the newly formingKolbeinsey Ridgepropagated northwards fromIceland,splitting theJan Mayen Microcontinentaway from theGreenland plate.As the Kolbeinsey Ridge formed, so activity on the Aegir Ridge reduced, ceasing completely at the end of theOligoceneepoch when the Kolbeinsey Ridge reached theJan Mayen Fracture Zone.[1]
The relatively thin crust and short lifespan of the Aegir Ridge is anomalous given its proximity to theIceland hotspot.Mantlehotspotsdeliver warm, actively-upwelling material to mid-ocean ridges, increasing mantle melting and crustal production. Likely, the stresses associated with plate tectonics and the mechanical structure of thelithospherecreated a situation in which spreading at the Kolbeinsey Ridge was energetically favorable to spreading at the Aegir Ridge. As the Kolbeinsey Ridge began rifting, hotspot material would then draw out of the Aegir Ridge and flow preferentially towards the Kolbeinsey Ridge, leading to the ultimate extinction of the spreading center.[2]
See also
[edit]References
[edit]- ^Greenhalgh, E.E.; Kusznir N.J. (2007)."Evidence for thin oceanic crust on the extinct Aegir Ridge, Norwegian Basin, NE Atlantic derived from satellite gravity inversion"(PDF).Geophysical Research Letters.34(L06305): L06305.Bibcode:2007GeoRL..34.6305G.doi:10.1029/2007GL029440.Retrieved13 October2010.
- ^Howell, Samuel M.; Ito, Garrett; Breivik, Asbjørn J.; Rai, Abhishek; Mjelde, Rolf; Hanan, Barry; Sayit, Kaan; Vogt, Peter (2014-04-15). "The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day".Earth and Planetary Science Letters.392:143–153.Bibcode:2014E&PSL.392..143H.doi:10.1016/j.epsl.2014.02.020.hdl:10125/41133.
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