Mantle plumes: heat-flow near Iceland

Stein, Carol A.; Stein, Seth

doi:10.1046/j.1468-4004.2003.44108.x

Cited by 23 publications

(6 citation statements)

References 30 publications

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“…To the north of the Charlie Gibbs Fracture Zone, high thermal anomalies do appear around Iceland, but neither Iceland itself nor the proximal Jan Mayen microcontinent and the Iceland transverse ridge (including the Greenland‐Iceland and Iceland‐Faeroe ridges, abbreviated as GIR and IFR, respectively) are anomalously hot, especially on the Z b map estimated from EMAG2. This may explain why Iceland shows no evidence for significantly higher temperatures associated with a mantle plume [ Stein and Stein , ] and leaves further speculations on whether the Icelandic lithosphere is rather colder than hotter [ Menke and Levin , ; Menke et al ., ; Foulger et al ., ], and whether Iceland is associated with a geochemical or a thermal anomaly [ Anderson , ; Foulger , ]. There are also other uncertainties and difficulties in interpreting estimated bottom of magnetic sources beneath Iceland, arising from a deep Moho serving likely as a local magnetic boundary, and from possible changes in the fractal parameter, in the Curie temperature due to a geochemical anomaly, and/or in the magnetic data specifications.…”

Section: Estimating Curie‐point Depths Of North Atlanticmentioning

confidence: 99%

Thermal evolution of the North Atlantic lithosphere: New constraints from magnetic anomaly inversion with a fractal magnetization model

Wang

Lin

et al. 2013

Geochem Geophys Geosyst

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[1] Using recently published global magnetic models, we present the first independent constraint on North Atlantic geothermal state and mantle dynamics from magnetic anomaly inversion with a fractal magnetization model. Two theoretical models of radial amplitude spectrum of magnetic anomalies are found almost identical, and both are applicable to detecting Curie depths in using the centroid method based on spectral linearization at certain wave number bands. Theoretical and numerical studies confirm the robustness of this inversion scheme. A fractal exponent of 3.0 in the magnetic susceptibility is found suitable, and Curie depths are well constrained by their known depths near the mid-Atlantic ridge. While generally increasing with growing ages, North Atlantic Curie depths show large oscillating and heterogeneous patterns related most likely to small-scale sublithospheric convections, which are found to have an onset time around 40 Ma and a scale of about 500 km, and are in preferred transverse rolls. Hotspots in North Atlantic also contribute to large geothermal and Curie-depth variations, but they appear to connect more closely to geochemical anomalies or small-scale convection than to mantle plumes. Curie depths can be correlated to heat flow gridded in a constant 1 interval, which reveals decreasing effective thermal conductivity with depths within the magnetic layer. North Atlantic Curie points are mostly beneath the Moho, suggesting that the uppermost mantle is magnetized from serpentinization and induces long-wavelength magnetic anomalies. Small-scale convection and serpentinization together may cause apparent flattening and deviations in heat flow and bathymetry from theoretical cooling models in old oceanic lithosphere.

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Section: Estimating Curie‐point Depths Of North Atlanticmentioning

confidence: 99%

Thermal evolution of the North Atlantic lithosphere: New constraints from magnetic anomaly inversion with a fractal magnetization model

Wang

Lin

et al. 2013

Geochem Geophys Geosyst

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“…Now it is thought, however, that plumes sway in the mantle wind and need not be fixed (Steinberger and O'Connell, 1998). Many think of "hotspots"-locations of intraplate volcanism-as thermal plumes, but most hotspots are thought to be no hotter than average (Stein and Stein, 2003;DeLaughter et al, this volume;Green and Falloon, this volume). Several classic "plumes" show no evidence for an initial head phase (e.g., Hawaii) or a tail phase (e.g., Siberia, Ontong-Java), and several plume proponents now suggest that the classic model is too restrictive and that not all plumes need have heads or tails, and not all plumes need be deep-sourced (e.g., Cserepes and Yuen, 2000).…”

Section: Introductionmentioning

confidence: 99%

From Deccan to Réunion: No trace of a mantle plume

Sheth¹

2005

Plates, Plumes and Paradigms

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The widely accepted mantle plume model postulates that (1) the currently volcanically active Réunion Island in the Indian Ocean is fed by the narrow "tail" of a mantle plume that rises from the core-mantle boundary, (2) the Deccan continental flood basalt province of India originated from the "head" of the same plume during its early eruptive phase near the end of the Cretaceous, and (3) the LakshadweepChagos Ridge, an important linear volcanic ridge in the Indian Ocean, is a product of the plume. It is not generally appreciated, however, that this "classic" case of a plume contradicts the plume model in many ways. For example, there is little petrological evidence as yet that the Deccan source was "abnormally hot," and the short (~1.0-0.5 m.y.) duration claimed by some for the eruption of the Deccan is in conflict with recent Ar-Ar age data that suggest that the total duration was at least ~8 m.y. The Deccan continental flood basalts (CFB) were associated with the break-off of the Seychelles microcontinent from India. Geological and geophysical data from the Deccan provide no support for the plume model and arguably undermine it altogether. The interplay of several intersecting continental rift zones in India is apparently responsible for the roughly circular outcrop of the Deccan. The Lakshadweep-Chagos Ridge and the islands of Mauritius and Réunion are located along fracture zones, and the apparent systematic age progression along the ridge may be a result of southward crack propagation through the oceanic lithosphere. This idea avoids the problem of a 10 o paleolatitude discrepancy which the plume model can solve only with the ad hoc inclusion of mantle roll. Published Ar-Ar age data for the Lakshadweep-Chagos Ridge basalts have been seriously questioned, and geochemical data suggest that they likely represent postshield volcanism and so are unsuitable for hotspot-based plate reconstructions. "Enriched" isotopic ratios, such as values of 87 Sr/ 86 Sr higher than those for normal mid-ocean ridge basalts, which have been observed in basalts of the ridge and the Mascarene Islands, may mark the involvement of delaminated enriched continental mantle instead of a plume. High values of 3 He/ 4 He also do not represent a deep mantle component or plume. The three Mascarene islands (Mauritius, Réunion, and Rodrigues) are not related to the Deccan but reflect the recent (post-10 Ma) tectonicmagmatic development of the Africa Plate. I relate CFB volcanism to continental rifting, which often (but not always) evolves into full-fledged seafloor spreading. I ascribe the rifting itself not to mantle plume heads but to large-scale plate dynamics themselves, possibly aided by long-term thermal insulation beneath a supercontinent that may have surface effects similar to those predicted for "plume incubation" models. 477on May 26, 2015 specialpapers.gsapubs.org Downloaded from Nonplume plate tectonic models are capable of explaining the Deccan in all its greatness, and there is no trace of a mantle plume in this vast region.

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“…The reconstructed subsidence histories of the rifted margins and the modeling of rare earth element data (Kerr, 1995) do seem to indicate a moderate thermal anomaly in the North Atlantic during breakup. However, modern heatflow (Stein and Stein, 2003), seismic and geochemical data (Foulger et al, this volume), as well as the subsidence evidence from the Iceland-Faeroe Ridge do not indicate a significant thermal anomaly under the area today.…”

Section: Temperature Anomaliesmentioning

confidence: 88%

Sedimentary evidence for moderate mantle temperature anomalies associated with hotspot volcanism

Clift¹

2005

Plates, Plumes and Paradigms

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One of the characteristics of deep-rooted mantle plume models, and the hotspot volcanism with which they are associated is the presence of anomalously buoyant asthenosphere underlying the lithospheric plate. The presence of hot, upwelling, lowdensity asthenosphere causes shallowing of the seafloor over the plume center. It is commonly assumed that as the plume mantle disperses, greater subsidence occurs compared to normal oceanic crust. However, in this paper analysis of the sedimentary cover from a range of hotspot-related seamounts, plateaus, and ridges of various ages from all major ocean basins shows either no subsidence anomalies or only moderate ones that can be linked to hot asthenosphere during hotspot magmatism. Assuming that all the uplift is caused by excess mantle heat, temperature anomalies rarely exceed 100 °C for a plume head ~100 km thick and could be somewhat lower if dynamic flow or composition are important causes of uplift. On the Ontong-Java Plateau, Mid-Pacific Mountains, Emperor Seamounts, Hess Rise, and MIT Guyot, subsidence is slower than for normal oceanic lithosphere, suggesting either colder than normal mantle temperatures or, more likely, the formation of a buoyant lithospheric root under the hotspot province at the time of its formation.

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Mantle plumes: heat-flow near Iceland

Cited by 23 publications

References 30 publications

Thermal evolution of the North Atlantic lithosphere: New constraints from magnetic anomaly inversion with a fractal magnetization model

Thermal evolution of the North Atlantic lithosphere: New constraints from magnetic anomaly inversion with a fractal magnetization model

From Deccan to Réunion: No trace of a mantle plume

Sedimentary evidence for moderate mantle temperature anomalies associated with hotspot volcanism

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