Iceland hotspot track

Lawver, Lawrence A.; Müller, R. Dietmar

doi:10.1130/0091-7613(1994)022<0311:iht>2.3.co;2

Cited by 344 publications

(199 citation statements)

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“…Heat flow is lower west of the Mid-Atlantic Ridge than east of it, the opposite of what is predicted by the conventional model of an eastwardmigrating plume [Lawver & Muller, 1994]. Heat flow is intrinsically insensitive to mantle temperature, however, and cannot rule out an anomaly of 100-200˚C.…”

Section: The North Atlantic Igneous Provincementioning

confidence: 64%

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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Section: The North Atlantic Igneous Provincementioning

confidence: 64%

Are ‘hot spots’ hot spots?

Foulger

2012

Journal of Geodynamics

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“…Map of the North Atlantic region at the time of magnetic anomaly 24 (from Larsen, Saunders, Clift, et al, 1994). Points A, B, and C indicate the postulated locations of the axis of the Iceland plume from Duncan (1984), Lawver and Müller (1994), and White and McKenzie (1989), respectively. The locations of onshore and offshore early Tertiary volcanic sequences and drilling transects on the SDRS are also indicated.…”

Section: Methodsmentioning

confidence: 99%

“…White and McKenzie (1989), as well as others (Gill et al, 1992;Larsen et al, 1992), assume that the ancestral Iceland plume axis was situated beneath the Kangerlussuaq area in East Greenland, although a number of models of relative plate motions place the axis 300−500 km to the northwest of that site ( Fig. 1; Duncan and Richards, 1991;Lawver and Müller, 1994). However compelling we find the plume models, the role of the ancestral Iceland plume in southeast Greenland Margin volcanism must be critically evaluated by assessing the involvement of thermally and/or compositionally anomalous mantle source regions for the igneous products.…”

Section: Introductionmentioning

confidence: 99%

Mantle melting systematics: transition from continental to oceanic volcanism on the southeast Greenland Margin

Fram¹,

Lesher²,

Volpe³

1998

Proceedings of the Ocean Drilling Program

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We present trace element analyses of basaltic and picritic lavas recovered from the Ocean Drilling Program Leg 152 transect on the southeast Greenland volcanic rifted margin. These lavas span the stratigraphic interval from continental to oceanic magmatism. Incompatible element patterns define two geochemical groups within the Site 917 upper series. Group 1 flows are characterized by (La/Sm) N = 0.3−0.8, whereas group 2 flows have (La/Sm) N = 0.7−1.2 and higher mantle-normalized Th, Ba, and Pb, and lower Nb and U concentrations. The transition upsection from group 1 to group 2 at Site 917 occurs between 114 and 65 meters below seafloor, and is represented by interfingering of flows belonging to the two groups. (La/Sm) N , Ba/Zr, and Th/Pb ratios and mantle-normalized incompatible element concentrations decrease systematically with stratigraphic height within each group, and the Site 915 and Site 918 units are generally continuous with group 2. These variations imply an increase in the extent of partial melting with time. Lu/Hf ratios vary from 0.14 to 0.25 through the upper series and into the Site 915 and Site 918 flows. This relationship suggests the importance of residual garnet in the mantle source melting decreased with time. We develop a quantitative model for mantle melting to investigate melting systematics responsible for these relationships. Comparison between observed data and model results suggests a progressive increase in the extent of partial melting (from 4% to 12%) and decrease in mean pressure of melting with time. This temporal evolution of primary magma compositions is explicable by rapid thinning of the continental lithosphere during eruption of the upper series. We conclude that group 1 units were derived from mantle with normal mid-ocean-ridge basalt source characteristics, whereas units from group 2 and from Sites 915 and 918 were derived from a source similar to depleted Icelandic mantle. We infer that the thermal anomaly associated with the ancestral Iceland plume pre-dated the transition in mantle source compositions.

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“…2), although the lack of a documented age progression along the presumed hotspot track leads to large uncertainties in the relative location of the hotspot through time (e.g. Lawver and Müller, 1994;Mihalffy et al, 2008;Steinberger, 2000). In pre-and earlybreakup history, hotspot influence was widespread, with no clear asymmetry.…”

Section: Introductionmentioning

confidence: 99%

“…Plume influence along the RR at this time is inferred from smooth basement topography created by the part of the RR spreading obliquely (Müller et al, 2008) showing the tectonic evolution of the study area. Filled circles mark estimated center of hotspot relative to Greenland by Lawver and Müller (1994) (red) and Mihalffy et al (2008) (purple). Dashed circles show corresponding (like colors) areas of influence of the Iceland plume for perfectly circular plume pancakes when the Aegir Ridge became extinct ∼25 Ma, based on the distance to the rough-smooth boundary in seafloor fabric created at the Reykjanes Ridge at 25 Ma.…”

Section: Introductionmentioning

confidence: 99%

The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day

Howell

Ito

Breivik

et al. 2014

Earth and Planetary Science Letters

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The Iceland hotspot has profoundly influenced the creation of oceanic crust throughout the North Atlantic basin. Enigmatically, the geographic extent of the hotspot influence along the Mid-Atlantic Ridge has been asymmetric for most of the spreading history. This asymmetry is evident in crustal thickness along the present-day ridge system and anomalously shallow seafloor of ages ∼49-25 Ma created at the Reykjanes Ridge (RR), SSW of the hotspot center, compared to deeper seafloor created by the nowextinct Aegir Ridge (AR) the same distance NE of the hotspot center. The cause of this asymmetry is explored with 3-D numerical models that simulate a mantle plume interacting with the ridge system using realistic ridge geometries and spreading rates that evolve from continental breakup to present-day. The models predict plume-influence to be symmetric at continental breakup, then to rapidly contract along the ridges, resulting in widely influenced margins next to uninfluenced oceanic crust. After this initial stage, varying degrees of asymmetry along the mature ridge segments are predicted. Models in which the lithosphere is created by the stiffening of the mantle due to the extraction of water near the base of the melting zone predict a moderate amount of asymmetry; the plume expands NE along the AR ∼70-80% as far as it expands SSW along the RR. Without dehydration stiffening, the lithosphere corresponds to the near-surface, cool, thermal boundary layer; in these cases, the plume is predicted to be even more asymmetric, expanding only 40-50% as far along the AR as it does along the RR. Estimates of asymmetry and seismically measured crustal thicknesses are best explained by model predictions of an Iceland plume volume flux of ∼100-200 m 3 /s, and a lithosphere controlled by a rheology in which dehydration stiffens the mantle, but to a lesser degree than simulated here. The asymmetry of influence along the present-day ridge system is predicted to be a transient configuration in which plume influence along the Reykjanes Ridge is steady, but is still widening along the Kolbeinsey Ridge, as it has been since this ridge formed at ∼25 Ma.

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Iceland hotspot track

Cited by 344 publications

References 0 publications

Are ‘hot spots’ hot spots?

Are ‘hot spots’ hot spots?

Mantle melting systematics: transition from continental to oceanic volcanism on the southeast Greenland Margin

The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day

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