Pervasive upper mantle melting beneath the western US. / Hier-Majumder, Saswata; Tauzin, Benoit.

In: Earth and Planetary Science Letters, Vol. 463, 01.04.2017, p. 25-35.

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Pervasive upper mantle melting beneath the western US. / Hier-Majumder, Saswata; Tauzin, Benoit.

In: Earth and Planetary Science Letters, Vol. 463, 01.04.2017, p. 25-35.

Research output: Contribution to journalArticle

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Hier-Majumder, S & Tauzin, B 2017, 'Pervasive upper mantle melting beneath the western US', Earth and Planetary Science Letters, vol. 463, pp. 25-35. https://doi.org/10.1016/j.epsl.2016.12.041

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Hier-Majumder, Saswata ; Tauzin, Benoit. / Pervasive upper mantle melting beneath the western US. In: Earth and Planetary Science Letters. 2017 ; Vol. 463. pp. 25-35.

BibTeX

@article{e97a334ff8cc4af68df2976093204ee6,
title = "Pervasive upper mantle melting beneath the western US",
abstract = "We report from converted seismic waves, a pervasive seismically anomalous layer above the transition zone beneath the western US. The layer, characterized by an average shear wave speed reduction of 1.6{\%}, spans over an area of ∼1.8×10^6 km2 with thicknesses varying between 25 and 70 km. The location of the layer correlates with the present location of a segment of the Farallon plate. This spatial correlation and the sharp seismic signal atop of the layer indicate that the layer is caused by compositional heterogeneity. Analysis of the seismic signature reveals that the compositional heterogeneity can be ascribed to a small volume of partial melt (0.5 ± 0.2 vol{\%} on average). This article presents the first high resolution map of the melt present within the layer. Despite spatial variations in temperature, the calculated melt volume fraction correlates strongly with the amplitude of P–S conversion throughout the region. Comparing the values of temperature calculated from the seismic signal with available petrological constraints, we infer that melting in the layer is caused by release of volatiles from the subducted Farallon slab. This partially molten zone beneath the western US can sequester at 1.2×10^(17) kg of volatiles, and can act as a large regional reservoir of volatile species such as H or C.",
author = "Saswata Hier-Majumder and Benoit Tauzin",
year = "2017",
month = "4",
day = "1",
doi = "10.1016/j.epsl.2016.12.041",
language = "English",
volume = "463",
pages = "25--35",
journal = "Earth and Planetary Science Letters",
issn = "0012-821X",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - Pervasive upper mantle melting beneath the western US

AU - Hier-Majumder, Saswata

AU - Tauzin, Benoit

PY - 2017/4/1

Y1 - 2017/4/1

N2 - We report from converted seismic waves, a pervasive seismically anomalous layer above the transition zone beneath the western US. The layer, characterized by an average shear wave speed reduction of 1.6%, spans over an area of ∼1.8×10^6 km2 with thicknesses varying between 25 and 70 km. The location of the layer correlates with the present location of a segment of the Farallon plate. This spatial correlation and the sharp seismic signal atop of the layer indicate that the layer is caused by compositional heterogeneity. Analysis of the seismic signature reveals that the compositional heterogeneity can be ascribed to a small volume of partial melt (0.5 ± 0.2 vol% on average). This article presents the first high resolution map of the melt present within the layer. Despite spatial variations in temperature, the calculated melt volume fraction correlates strongly with the amplitude of P–S conversion throughout the region. Comparing the values of temperature calculated from the seismic signal with available petrological constraints, we infer that melting in the layer is caused by release of volatiles from the subducted Farallon slab. This partially molten zone beneath the western US can sequester at 1.2×10^(17) kg of volatiles, and can act as a large regional reservoir of volatile species such as H or C.

AB - We report from converted seismic waves, a pervasive seismically anomalous layer above the transition zone beneath the western US. The layer, characterized by an average shear wave speed reduction of 1.6%, spans over an area of ∼1.8×10^6 km2 with thicknesses varying between 25 and 70 km. The location of the layer correlates with the present location of a segment of the Farallon plate. This spatial correlation and the sharp seismic signal atop of the layer indicate that the layer is caused by compositional heterogeneity. Analysis of the seismic signature reveals that the compositional heterogeneity can be ascribed to a small volume of partial melt (0.5 ± 0.2 vol% on average). This article presents the first high resolution map of the melt present within the layer. Despite spatial variations in temperature, the calculated melt volume fraction correlates strongly with the amplitude of P–S conversion throughout the region. Comparing the values of temperature calculated from the seismic signal with available petrological constraints, we infer that melting in the layer is caused by release of volatiles from the subducted Farallon slab. This partially molten zone beneath the western US can sequester at 1.2×10^(17) kg of volatiles, and can act as a large regional reservoir of volatile species such as H or C.

U2 - 10.1016/j.epsl.2016.12.041

DO - 10.1016/j.epsl.2016.12.041

M3 - Article

VL - 463

SP - 25

EP - 35

JO - Earth and Planetary Science Letters

JF - Earth and Planetary Science Letters

SN - 0012-821X

ER -