Seismic evidence for a tilted mantle plume and north–south mantle flow beneath Iceland

Shen, Yang; Solomon, Sean C.; Bjarnason, Ingi Þorleifur; Nolet, Guust; Morgan, W. Jason; Allen, R. M.; Vogfjörd, K. S.; Jakobsdóttir, Steinunn S.; Stefánsson, Ragnar; Julian, Bruce R.; Foulger, G. R.

doi:10.1016/s0012-821x(02)00494-6

Cited by 79 publications

(71 citation statements)

References 48 publications

(56 reference statements)

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“…The P660s3P410s time of the Thin TZ Gala ¤pagos dataset (21.4 þ 0.7 s) is similar to that determined for Iceland and inferred for the Society hotspot. On the basis of these results we conclude that the thermal anomaly inferred for the Gala ¤pagos (130 þ 60 K) is comparable that beneath the Iceland and Society hotspots [15,17,20,24], while the thermal anomaly of the Hawaiian plume [18] is about twice as large.…”

Section: Concluding Discussionmentioning

confidence: 53%

“…6). Receiver function data from the Gala ¤pagos and Iceland [15,17,20] are consistent with both low upper mantle velocities and thinning of the transition zone in regions near the presumed location of plume upwelling. In addition, an SS precursor study at the Society hotspot also shows thinning of the transition zone [24].…”

Section: Concluding Discussionmentioning

confidence: 55%

“…In particular, the arrival times of S-waves converted from teleseismic P-waves at the transition zone discontinuities [15,17,18,20] and underside re£ections of S-waves from these discontinuities (SS precursors) [24] indicate a localized thinning of the transition zone, a result consistent with a thermal anomaly and plumelike upwelling. Comparison of the thermal structure beneath the Gala ¤pagos with these other oceanic hotspots is particularly interesting for several reasons.…”

Section: Introductionmentioning

confidence: 89%

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Anomalously thin transition zone beneath the Galápagos hotspot

Hooft

Toomey

Solomon

2003

Earth and Planetary Science Letters

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Differential arrival times of P-to-S conversions at 410 and 660 km depth, measured from radial receiver functions, are used to determine the thickness of the mantle transition zone beneath the Gala ¤pagos hotspot. For an area of approximately 700 km 2 surrounding the Gala ¤pagos archipelago, P660s3P410s times are not significantly different from those for the Pacific Basin. In contrast, a subset of the Gala ¤pagos data yields differential times indicating thinning of the mantle transition zone by 18 þ 8 km within an area approximately 100 km in radius centered about 40 km southwest of the center of the island of Fernandina. This anomaly is consistent with an excess temperature of 130 þ 60 K within this volume of the transition zone, comparable to that inferred beneath the Iceland and Society hotspots. The most straightforward interpretation of this anomaly is that a mantle plume upwelling from depths greater than 410 km underlies the Gala ¤pagos hotspot. ß

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Section: Concluding Discussionmentioning

confidence: 53%

Section: Concluding Discussionmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 89%

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Anomalously thin transition zone beneath the Galápagos hotspot

Hooft

Toomey

Solomon

2003

Earth and Planetary Science Letters

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“…The 410-km discontinuity is at normal depth beneath most of Iceland, providing no evidence for a temperature anomaly. It is ~ 20 km deeper than average beneath a small region in centralsouthern Iceland [Du et al, 2006;Shen et al, 2002]. This deepening can be explained by ~ 200˚C higher T P , a few mole % higher magnesian olivine, relatively dry conditions, or a combination of some or all these effects.…”

Section: The North Atlantic Igneous Provincementioning

confidence: 89%

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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“…It was extensively applied in purported plume localities where the task at hand was commonly to identify the place where the TZ appeared to be thinnest and to propose this as the TZ-crossing place of the assumed hot plume. Offsets from the surface location of most intense volcanism were explained as tilting plumes (e.g., Shen et al, 2002), mantle wind (e.g., Steinberger et al, 2004), or disruption of the assumed plume conduit by upper-mantle structural complications (e.g., Fee and Dueker, 2004).…”

Section: The Transition Zonementioning

confidence: 99%

The Yellowstone “hot spot” track results from migrating basin-range extension

Foulger

Christiansen

Anderson

Geological Society of America Special Papers

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Whether the volcanism of the Columbia River Plateau, Eastern Snake River Plain, and Yellowstone is related to a mantle plume or to plate tectonic processes is a long-standing controversy. There are many geological mismatches with the basic plume model as well as logical flaws, such as citing data postulated to require a deep-mantle origin in support of an 'upper-mantle plume' model. USArray has recently yielded abundant new seismological results, but despite this, seismic analyses have still not resolved the disparity of opinion. This suggests that seismology may be unable to resolve the plume question for Yellowstone, and perhaps elsewhere. USArray data have inspired many new models that relate Western USA volcanism to shallow mantle convection associated with subduction zone processes. Many of these models assume that the principal requirement for surface volcanism is melt in the mantle and that the lithosphere is essentially passive. In this paper we propose a pure plate model in which melt is commonplace in the mantle, and its inherent buoyancy is not what causes surface eruptions. Instead, it is extension of the lithosphere that permits melt to escape to the surface and eruptions to occur-the mere presence of underlying melt is not a sufficient condition. The time-progressive chain of rhyolitic calderas in the Eastern Snake River PlainYellowstone zone that has formed since basin-range extension began at ~ 17 Ma results from laterally migrating lithospheric extension and thinning that has permitted basaltic magma to rise from the upper mantle and melt the lower crust. We propose that this migration formed part of the systematic eastward migration of the axis of most intense basin-range extension. The bimodal rhyolite-basalt volcanism followed migration of the locus of most rapid extension, not vice versa. This model does not depend on seismology to test it but instead on surface geological observations. § Deceased.

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Seismic evidence for a tilted mantle plume and north–south mantle flow beneath Iceland

Cited by 79 publications

References 48 publications

Anomalously thin transition zone beneath the Galápagos hotspot

Anomalously thin transition zone beneath the Galápagos hotspot

Are ‘hot spots’ hot spots?

The Yellowstone “hot spot” track results from migrating basin-range extension

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