Global warming of the mantle at the origin of flood basalts over supercontinents

Coltice, Nicolas; Phillips, Benjamin; Bertrand, Hélène; Ricard, Yanick; Rey, Patrice

doi:10.1130/g23240a.1

Cited by 230 publications

(93 citation statements)

References 27 publications

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“…Seismology provides abundant evidence that the asthenospheric mantle is structurally and compositionally inhomogeneous, in particular at shallow depths. Factors such as the variable distribution of radioactive elements, the insulating effect of continents, and disruption of the asthenosphere by continental breakup and subduction cause T P to vary laterally by tens of degrees Celsius [Anderson, 1982;Coltice et al, 2007]. Mantle convection would not occur if T P did not vary.…”

Section: Discussionmentioning

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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Section: Discussionmentioning

confidence: 99%

Are ‘hot spots’ hot spots?

Foulger

2012

Journal of Geodynamics

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“…As a result we find that average temperatures below mobile oceanic plates are comparable to the temperatures below a supercontinent (Model C). The inclusion of plates over the entire surface of our model dampens the contrast [Coltice et al, 2007] between the mean temperature below the supercontinent and oceans. In comparison, heat can escape more readily from an ocean modeled by a free-slip surface condition [Monnereau and Quéré, 2001].…”

Section: Discussionmentioning

confidence: 99%

“…[2] The lack of participation of the thick continental lithosphere in global mantle circulation and a radioactively enriched continental crust suggest that continental plates act as buoyant thermal insulators [Anderson, 1982;Lenardic et al, 2005;Phillips and Bunge, 2007;Coltice et al, 2007]. In addition, it has been argued that supercontinent assembly results in subcontinental warming because the underlying mantle is isolated from the cooling associated with subduction [Anderson, 1994].…”

Section: Introductionmentioning

confidence: 99%

Thermal response of the mantle following the formation of a “super‐plate”

Heron

Lowman

2010

Geophysical Research Letters

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[1] Evidence indicating that the mantle below Pangea was characterized by elevated temperatures supports the widely held view that a supercontinent insulates the underlying mantle. Implementing a 3D model of mantle convection featuring distinct oceanic and continental plates, we explore different effects of supercontinent formation on mantle evolution. We find that a halt in subduction along the margins of the site of the continental collision is sufficient to enable the formation of mantle plumes below a composite "super-plate" and that the addition of continental properties that contribute to insulation have little effect on sub-continental temperature. Our findings show that the mean temperature below a supercontinent surpasses that below the oceanic plates when the former is a perfect insulator but that continental thermal insulation plays only a minor role in the growth of sub-supercontinent mantle plumes. We suggest that the growth of a super-oceanic plate can equally encourage the appearance of underlying upwellings. Citation: Heron, P. J., and J. P. Lowman (2010), Thermal response of the mantle following the formation of a "super-plate," Geophys.

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“…In the case of the Early Ordovician Bay of Islands and Betts Cove ophiolites, they likely formed at a fore-arc ridge axis normal to the arc trench trend (Dewey and Casey 2013). Intermediate mantle potential temperature estimates (i.e., 1400 and 1500°C) of basaltic rocks are interpreted to be related to heat incubation beneath moderately thickened crust in the case of some continental large igneous provinces (e.g., Ferrar and Central Atlantic Magmatic Province) or, in the case of some Cenozoic oceanic islands, as evidence of cool, lowmelt-fraction magmas from the periphery of a mantle plume (Coltice et al 2007;Herzberg and Gazel 2009;Hole 2015 cooling plume (Herzberg and Asimow 2008;Herzberg and Gazel 2009). Alternatively it could be that some basalt from the Bay of Islands and Betts Cove ophiolites formed within slightly thicker oceanic crust as the ridge was intersecting the arc trench.…”

Section: Discussionmentioning

confidence: 99%

Mantle Potential Temperature Estimates of Basalt from the East Taiwan Ophiolite

Shellnutt¹,

Hsieh

2016

Terr. Atmos. Ocean. Sci.

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The East Taiwan Ophiolite (ETO) is a fragment of the eastern-most South China Sea that was accreted to the Eurasian margin during the Pliocene and is a member of the Western Pacific and Cordilleran belt ophiolite group. Ophiolites from the Western Pacific and Cordilleran belt are typically subduction-related (i.e., supra-subduction or volcanic-arc) but the ETO is compositionally, isotopically and mineralogically similar to subduction-unrelated ophiolites. The primary melt compositions of ETO basaltic rocks were calculated and range from high-Mg basalt to picrite (i.e., MgO = 10 to 14 wt%). The mantle potential temperature (T P ) estimates are within the range of ambient mantle (1300 -1400°C) and other mid-ocean ridge ophiolites (i.e., Macquarie Island and Masirah) indicating that it is consistent with a mid-ocean ridge setting. Mantle potential temperature estimates for rocks from a mantle-plume-type ophiolite (i.e., 1620 -1630°C) are anomalously high whereas rocks from supra-subduction zone ophiolites show a wider range that extends from ambient (i.e., Troodos and Semail) T P to very high (i.e., Betts Cove and Bay of Islands) T P .

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Global warming of the mantle at the origin of flood basalts over supercontinents

Cited by 230 publications

References 27 publications

Are ‘hot spots’ hot spots?

Are ‘hot spots’ hot spots?

Thermal response of the mantle following the formation of a “super‐plate”

Mantle Potential Temperature Estimates of Basalt from the East Taiwan Ophiolite

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