Crustal structure above the Iceland mantle plume imaged by the ICEMELT refraction profile

Darbyshire, F. A.; Bjarnason, Ingi Þorleifur; White, R. S.; Flóvenz, Ólafur G.

doi:10.1046/j.1365-246x.1998.00701.x

Cited by 139 publications

(215 citation statements)

References 39 publications

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“…The maximum value is found on the ICEMELT line ( Fig. 5b) (Darbyshire et al 1998) in central SE Iceland above the postulated centre of the Iceland plume (Darbyshire et al 2000). However, there is an alternative explanation for the presence of thick crust beneath that region.…”

Section: Greenland -Iceland -Faroe Ridgementioning

confidence: 90%

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A review of the NE Atlantic conjugate margins based on seismic refraction data

Funck

Gaina

Geissler

et al. 2016

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The NE Atlantic region evolved through several rift episodes, leading to break-up in the Eocene that was associated with voluminous magmatism along the conjugate margins of East Greenland and NW Europe. Existing seismic refraction data provide good constraints on the overall tectonic development of the margins, despite data gaps at the NE Greenland shear margin and the southern Jan Mayen microcontinent. The maximum thickness of the initial oceanic crust is 40 km at the Greenland-Iceland-Faroe Ridge, but decreases with increasing distance to the Iceland plume. High-velocity lower crust interpreted as magmatic underplating or sill intrusions is observed along most margins but disappears north of the East Greenland Ridge and the Lofoten margin, with the exception of the Vestbakken Volcanic Province at the SW Barents Sea margin. South of the narrow Lofoten margin, the European side is characterized by wide margins. The opposite trend is seen in Greenland, with a wide margin in the NE and narrow margins elsewhere. The thin crust beneath the basins is generally underlain by rocks with velocities of .7 km s 21 interpreted as serpentinized mantle in the Porcupine and southern Rockall basins; while off Norway, alternative interpretations such as eclogite bodies and underplating are also discussed.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.

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Section: Greenland -Iceland -Faroe Ridgementioning

confidence: 90%

“…1) where thick igneous crust in excess of 30 km is observed (Darbyshire et al 1998;Richardson et al 1998;Holbrook et al 2001). The crustal thickness is the result of enhanced melting in the Iceland mantle plume (White & McKenzie 1995).…”

Section: Geological Settingmentioning

confidence: 99%

A review of the NE Atlantic conjugate margins based on seismic refraction data

Funck

Gaina

Geissler

et al. 2016

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“…Controlled source experiments on Iceland have revealed Vp/Vsratios in oceanic layer 3 in the range 1.75e1.80 (Bjarnason et al, 1993;Brandsdottir et al, 1997;Staples et al, 1997;Darbyshire et al, 1998;Menke et al, 1998). These values are consistent with gabbro well below the solidus (Kampfmann and Berckhemer, 1985).…”

Section: Icelandic Type Oceanic Crustmentioning

confidence: 99%

Vp/Vs-ratios and anisotropy on the northern Jan Mayen Ridge, North Atlantic, determined from ocean bottom seismic data

et al. 2015

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a b s t r a c tIn order to gain insight into the lithology and crustal evolution of the northern Jan Mayen Ridge, North Atlantic, the horizontal components of an Ocean Bottom Seismometer (OBS) dataset were analyzed with regard to Vp/Vs-modeling and seismic anisotropy. The modeling suggests that the northernmost part of the ridge consists of Icelandic type oceanic crust, bordered to the north by anomalously thick oceanic crust formed at the Mohns spreading ridge. The modeled Vp/Vs-ratios suggest variations in gabbroic composition and present-day temperatures in the area. Anisotropy analysis reveals a fast S-wave component along the Jan Mayen Ridge. This pattern of anisotropy is most readily interpreted as dikes intruded along the ridge, suggesting that the magmatism can be related to the development of a leaky transform since Early Oligocene.

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“…The submarine Greenland-Iceland and Iceland-Faeroe ridges were studied with profiles hundreds of kilometres long. Long profiles were also shot on Iceland itself [Bott & Gunnarsson, 1980;Darbyshire et al, 1998;Holbrook et al, 2001]. The crust beneath these ridges was concluded to be ~ 30 km thick.…”

Section: The North Atlantic Igneous Provincementioning

confidence: 99%

Are ‘hot spots’ hot spots?

Foulger

2012

Journal of Geodynamics

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe term 'hot spot' emerged in the 1960's from speculations that Hawaii might have its origins in an unusually hot source region in the mantle. It subsequently become 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 midocean ridge basalts (MORB). 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 favor of one that does not assume a postulated origin, but is a description of unequivocal, observed char...

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Crustal structure above the Iceland mantle plume imaged by the ICEMELT refraction profile

Cited by 139 publications

References 39 publications

A review of the NE Atlantic conjugate margins based on seismic refraction data

A review of the NE Atlantic conjugate margins based on seismic refraction data

Vp/Vs-ratios and anisotropy on the northern Jan Mayen Ridge, North Atlantic, determined from ocean bottom seismic data

Are ‘hot spots’ hot spots?

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