Experimental evidence supports mantle partial melting in the asthenosphere

Chantel, Julien; Manthilake, Geeth; Andrault, Denis; Novella, Davide; Yu, Tony; Wang, Yanbin

doi:10.1126/sciadv.1600246

Cited by 114 publications

(139 citation statements)

References 69 publications

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“…The coldest and hottest petrological models (dark blue and dark red, respectively) are not consistent with seismic data. “HH” and “Ch” indicate if the model has been computed using the parameterization from Hammond and Humphreys (2000a, 2000b) or Chantel et al (), respectively (see also the legend in Figure 8). We also plot the

T_{normalP}

recently inferred from thermobarometry (Weit et al, ) (∼1,360°C; orange circle and band).…”

Section: Discussionmentioning

confidence: 99%

“…Melt fractions are computed based on a mantle‐peridotitic dry solidus and liquidus (Katz et al, , and references therein). The effects of melt on

V_{normalS}

and V

_{normalP}

are computed according to the two experimental models: Hammond and Humphreys (2000a, 2000b) and Chantel et al () (“HH” and “Ch,” respectively, in the legend in Figure ).…”

Section: Petrologically Derived Modelsmentioning

confidence: 99%

“…∼1% melt is present in model 1 from ∼85 to ∼140 km, in model 3 from ∼88 to ∼130 km, in model 4 from ∼95 to ∼122 km;

< \sim 0.5 %

melt is present in model 5 from ∼80 to ∼117 km; melt is absent in models 2 and 6. “HH” and “Ch” indicate whether the model has been computed using, respectively, the parameterization by Hammond and Humphreys (2000a, 2000b) or Chantel et al ().…”

Section: Petrologically Derived Modelsmentioning

confidence: 99%

“…Slight further smoothing of the

V_{normalS}

profiles is performed using a sliding boxcar window with a 20 km half width. In all our models, we correct for anelastic attenuation effects as in Fullea et al () but we also include melt related variations in the seismic quality factor (Q) based on the laboratory results by Chantel et al (). Surface elevation is modeled according to the local isostasy at lithospheric scale as described in Fullea et al ().…”

Section: Petrologically Derived Modelsmentioning

confidence: 99%

See 3 more Smart Citations

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

Bonadio

Geissler

Lebedev

et al. 2018

Geochem Geophys Geosyst

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Understanding the enigmatic intraplate volcanism in the Tristan da Cunha region requires knowledge of the temperature of the lithosphere and asthenosphere beneath it. We measured phase‐velocity curves of Rayleigh waves using cross‐correlation of teleseismic seismograms from an array of ocean‐bottom seismometers around Tristan, constrained a region‐average, shear‐velocity structure, and inferred the temperature of the lithosphere and asthenosphere beneath the hotspot. The ocean‐bottom data set presented some challenges, which required data‐processing and measurement approaches different from those tuned for land‐based arrays of stations. Having derived a robust, phase‐velocity curve for the Tristan area, we inverted it for a shear wave velocity profile using a probabilistic (Markov chain Monte Carlo) approach. The model shows a pronounced low‐velocity anomaly from 70 to at least 120 km depth. VnormalS in the low velocity zone is 4.1–4.2 km/s, not as low as reported for Hawaii (∼4.0 km/s), which probably indicates a less pronounced thermal anomaly and, possibly, less partial melting. Petrological modeling shows that the seismic and bathymetry data are consistent with a moderately hot mantle (mantle potential temperature of 1,410–1,430°C, an excess of about 50–120°C compared to the global average) and a melt fraction smaller than 1%. Both purely seismic inversions and petrological modeling indicate a lithospheric thickness of 65–70 km, consistent with recent estimates from receiver functions. The presence of warmer‐than‐average asthenosphere beneath Tristan is consistent with a hot upwelling (plume) from the deep mantle. However, the excess temperature we determine is smaller than that reported for some other major hotspots, in particular Hawaii.

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T_{normalP}

recently inferred from thermobarometry (Weit et al, ) (∼1,360°C; orange circle and band).…”

Section: Discussionmentioning

confidence: 99%

“…Melt fractions are computed based on a mantle‐peridotitic dry solidus and liquidus (Katz et al, , and references therein). The effects of melt on

V_{normalS}

and V

_{normalP}

are computed according to the two experimental models: Hammond and Humphreys (2000a, 2000b) and Chantel et al () (“HH” and “Ch,” respectively, in the legend in Figure ).…”

Section: Petrologically Derived Modelsmentioning

confidence: 99%

“…∼1% melt is present in model 1 from ∼85 to ∼140 km, in model 3 from ∼88 to ∼130 km, in model 4 from ∼95 to ∼122 km;

< \sim 0.5 %

Section: Petrologically Derived Modelsmentioning

confidence: 99%

“…Slight further smoothing of the

V_{normalS}

Section: Petrologically Derived Modelsmentioning

confidence: 99%

See 2 more Smart Citations

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

Bonadio

Geissler

Lebedev

et al. 2018

Geochem Geophys Geosyst

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show abstract

“…The typically gradual transition beneath cratons contrasts with bright laterally coherent negative S p phases observed beneath young continental lithosphere, which may imply the widespread presence of partial melt pooled at the top of the asthenosphere in those regions (Ford et al, ; Hansen et al, ; Hopper et al, ). In terms of lithosphere dynamics, pervasive partial melt pooled beneath the base of Phanerozoic lithosphere would likely reduce mantle viscosity (Chantel et al, ; Holtzman, ), creating a weak layer that decouples the plate motions from deeper mantle flow (Becker, ). The stark contrasts between the lithosphere‐asthenosphere transition beneath cratons and younger continents—likely related to differences in the distribution of volatiles and partial melt—suggest that the cratonic mantle lithosphere may be more strongly coupled to the deeper mantle than Phanerozoic mantle lithosphere (e.g., Miller & Becker, ).…”

Section: The Physical and Chemical Origins Of The Cratonic Labmentioning

confidence: 99%

How Sharp Is the Cratonic Lithosphere‐Asthenosphere Transition?

Mancinelli

Fischer

Dalton

2017

Geophysical Research Letters

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Earth's cratonic mantle lithosphere is distinguished by high seismic wave velocities that extend to depths greater than 200 km, but recent studies disagree on the magnitude and depth extent of the velocity gradient at their lower boundary. Here we analyze and model the frequency dependence of Sp waves to constrain the lithosphere‐asthenosphere velocity gradient at long‐lived stations on cratons in North America, Africa, Australia, and Eurasia. Beneath 33 of 44 stations, negative velocity gradients at depths greater than 150 km are less than a 2–3% velocity drop distributed over more than 80 km. In these regions the base of the typical cratonic lithosphere is gradual enough to be explained by a thermal transition. Vertically sharper lithosphere‐asthenosphere transitions are permitted beneath 11 stations, but these zones are spatially intermittent. These results demonstrate that lithosphere‐asthenosphere viscosity contrasts and coupling fundamentally differ between cratons and younger continents.

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Effect of graphite on the electrical conductivity of the lithospheric mantle

Zhang

Yoshino

2017

Geochem Geophys Geosyst

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Graphite is considered as one of candidate to explain the high-conductivity anomalies revealed through magnetotelluric (MT) observations. To investigate the effect of interfacial energy on the interconnection of graphite in olivine matrix, we measured the electrical conductivity of polycrystalline San Carlos olivine mixed with 0.8 vol % graphite on the grain boundaries via impedance spectroscopy at 1 GPa and 300-1700 K in a cubic multianvil apparatus. The olivine-graphite dihedral angle of the recovered sample was also measured to determine interfacial energy between graphite and olivine. The bulk electrical conductivities and large activation enthalpy (1.32 eV) of the carbon-bearing sample were consistent with those of dry polycrystalline olivine. This behavior implies that graphite cannot be interconnected on olivine grain boundaries, which is also supported by the large dihedral angle (988) of the olivine/graphite system. Impedance spectroscopy measurements were performed at 3 GPa and a temperature of up to 1700 K for carbon-coated olivine bicrystal samples to investigate the stability of graphite films on the grain boundaries of silicate minerals under upper-mantle conditions. The conductivities rapidly or slowly dropped as a function of time and graphite film thickness during annealing at the target temperature. This phenomenon exhibits that graphite film on the olivine grain boundary is readily destroyed under upper-mantle conditions as supported by microstructural observations on the recovered carbon-coated olivine bicrystal samples. Higher interfacial energy and larger dihedral angle (988) between graphite and olivine would not allow the maintenance of graphite film on olivine grain boundaries. The activation enthalpy for the apparent disconnection rate of a graphite film on olivine grain boundaries is close to that of carbon diffusion in olivine grain boundaries, which suggests that the disconnection of the graphite film is likely to be controlled by carbon grain boundary diffusion. Therefore, graphite is an unlikely candidate to explain the highconductivity anomalies revealed by MT surveys in the upper mantle.

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Experimental evidence supports mantle partial melting in the asthenosphere

Abstract: Based on sound velocity measurements, upper mantle seismic anomalies could be explained by a melt fraction as low as 0.2%.

Cited by 114 publications

References 69 publications

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

How Sharp Is the Cratonic Lithosphere‐Asthenosphere Transition?

Effect of graphite on the electrical conductivity of the lithospheric mantle

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