Seismic evidence for Earth's crusty deep mantle

Daniel A. Frost, Sebastian Rost, Edward J. Garnero, Mingming Li

Research output: Research - peer-reviewArticle

  • 1 Citations

Abstract

Seismic tomography resolves anomalies interpreted as oceanic lithosphere subducted deep into Earth's lower mantle. However, the fate of the compositionally distinct oceanic crust that is part of the lithosphere is poorly constrained but provides important constraints on mixing processes and the recycling process in the deep Earth. We present high-resolution seismic array analyses of anomalous P-waves sampling the deep mantle, and deterministically locate heterogeneities in the lowermost 300 km of the mantle. Spectral analysis indicates that the dominant scale length of the heterogeneity is 4 to 7 km. The heterogeneity distribution varies laterally and radially and heterogeneities are more abundant near the margins of the lowermost mantle Large Low Velocity Provinces (LLVPs), consistent with mantle convection simulations that show elevated accumulations of deeply advected crustal material near the boundaries of thermo-chemical piles. The size and distribution of the observed heterogeneities is consistent with that expected for subducted oceanic crust. These results thus suggest the deep mantle contains an imprint of continued subduction of oceanic crust, stirred by mantle convection and modulated by long lasting thermo-chemical structures. The preferred location of the heterogeneity in the lowermost mantle is consistent with a thermo-chemical origin of the LLVPs. Our observations relate to the mixing behaviour of small length-scale heterogeneity in the deep Earth and indicate that compositional heterogeneities from the subduction process can survive for extended times in the lowermost mantle.

LanguageEnglish (US)
Pages54-63
Number of pages10
JournalEarth and Planetary Science Letters
Volume470
DOIs
StatePublished - Jul 15 2017

Fingerprint

mantle
Earth (planet)
Earth mantle
Convection
oceanic crust
Spectrum analysis
Piles
Tomography
Recycling
Sampling
crusts
mantle convection
subduction
chemical
distribution
province
lithosphere
low speed
convection
seismic tomography

Keywords

  • deep Earth
  • mantle dynamics
  • mantle structure
  • scattering
  • seismic arrays
  • seismology

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Seismic evidence for Earth's crusty deep mantle. / Frost, Daniel A.; Rost, Sebastian; Garnero, Edward J.; Li, Mingming.

In: Earth and Planetary Science Letters, Vol. 470, 15.07.2017, p. 54-63.

Research output: Research - peer-reviewArticle

Frost, Daniel A. ; Rost, Sebastian ; Garnero, Edward J. ; Li, Mingming. / Seismic evidence for Earth's crusty deep mantle. In: Earth and Planetary Science Letters. 2017 ; Vol. 470. pp. 54-63
@article{c2da72d9ffd849a1aca1909d3e81da2b,
title = "Seismic evidence for Earth's crusty deep mantle",
abstract = "Seismic tomography resolves anomalies interpreted as oceanic lithosphere subducted deep into Earth's lower mantle. However, the fate of the compositionally distinct oceanic crust that is part of the lithosphere is poorly constrained but provides important constraints on mixing processes and the recycling process in the deep Earth. We present high-resolution seismic array analyses of anomalous P-waves sampling the deep mantle, and deterministically locate heterogeneities in the lowermost 300 km of the mantle. Spectral analysis indicates that the dominant scale length of the heterogeneity is 4 to 7 km. The heterogeneity distribution varies laterally and radially and heterogeneities are more abundant near the margins of the lowermost mantle Large Low Velocity Provinces (LLVPs), consistent with mantle convection simulations that show elevated accumulations of deeply advected crustal material near the boundaries of thermo-chemical piles. The size and distribution of the observed heterogeneities is consistent with that expected for subducted oceanic crust. These results thus suggest the deep mantle contains an imprint of continued subduction of oceanic crust, stirred by mantle convection and modulated by long lasting thermo-chemical structures. The preferred location of the heterogeneity in the lowermost mantle is consistent with a thermo-chemical origin of the LLVPs. Our observations relate to the mixing behaviour of small length-scale heterogeneity in the deep Earth and indicate that compositional heterogeneities from the subduction process can survive for extended times in the lowermost mantle.",
keywords = "deep Earth, mantle dynamics, mantle structure, scattering, seismic arrays, seismology",
author = "Frost, {Daniel A.} and Sebastian Rost and Garnero, {Edward J.} and Mingming Li",
year = "2017",
month = "7",
doi = "10.1016/j.epsl.2017.04.036",
volume = "470",
pages = "54--63",
journal = "Earth and Planetary Sciences Letters",
issn = "0012-821X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Seismic evidence for Earth's crusty deep mantle

AU - Frost,Daniel A.

AU - Rost,Sebastian

AU - Garnero,Edward J.

AU - Li,Mingming

PY - 2017/7/15

Y1 - 2017/7/15

N2 - Seismic tomography resolves anomalies interpreted as oceanic lithosphere subducted deep into Earth's lower mantle. However, the fate of the compositionally distinct oceanic crust that is part of the lithosphere is poorly constrained but provides important constraints on mixing processes and the recycling process in the deep Earth. We present high-resolution seismic array analyses of anomalous P-waves sampling the deep mantle, and deterministically locate heterogeneities in the lowermost 300 km of the mantle. Spectral analysis indicates that the dominant scale length of the heterogeneity is 4 to 7 km. The heterogeneity distribution varies laterally and radially and heterogeneities are more abundant near the margins of the lowermost mantle Large Low Velocity Provinces (LLVPs), consistent with mantle convection simulations that show elevated accumulations of deeply advected crustal material near the boundaries of thermo-chemical piles. The size and distribution of the observed heterogeneities is consistent with that expected for subducted oceanic crust. These results thus suggest the deep mantle contains an imprint of continued subduction of oceanic crust, stirred by mantle convection and modulated by long lasting thermo-chemical structures. The preferred location of the heterogeneity in the lowermost mantle is consistent with a thermo-chemical origin of the LLVPs. Our observations relate to the mixing behaviour of small length-scale heterogeneity in the deep Earth and indicate that compositional heterogeneities from the subduction process can survive for extended times in the lowermost mantle.

AB - Seismic tomography resolves anomalies interpreted as oceanic lithosphere subducted deep into Earth's lower mantle. However, the fate of the compositionally distinct oceanic crust that is part of the lithosphere is poorly constrained but provides important constraints on mixing processes and the recycling process in the deep Earth. We present high-resolution seismic array analyses of anomalous P-waves sampling the deep mantle, and deterministically locate heterogeneities in the lowermost 300 km of the mantle. Spectral analysis indicates that the dominant scale length of the heterogeneity is 4 to 7 km. The heterogeneity distribution varies laterally and radially and heterogeneities are more abundant near the margins of the lowermost mantle Large Low Velocity Provinces (LLVPs), consistent with mantle convection simulations that show elevated accumulations of deeply advected crustal material near the boundaries of thermo-chemical piles. The size and distribution of the observed heterogeneities is consistent with that expected for subducted oceanic crust. These results thus suggest the deep mantle contains an imprint of continued subduction of oceanic crust, stirred by mantle convection and modulated by long lasting thermo-chemical structures. The preferred location of the heterogeneity in the lowermost mantle is consistent with a thermo-chemical origin of the LLVPs. Our observations relate to the mixing behaviour of small length-scale heterogeneity in the deep Earth and indicate that compositional heterogeneities from the subduction process can survive for extended times in the lowermost mantle.

KW - deep Earth

KW - mantle dynamics

KW - mantle structure

KW - scattering

KW - seismic arrays

KW - seismology

UR - http://www.scopus.com/inward/record.url?scp=85018420862&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85018420862&partnerID=8YFLogxK

U2 - 10.1016/j.epsl.2017.04.036

DO - 10.1016/j.epsl.2017.04.036

M3 - Article

VL - 470

SP - 54

EP - 63

JO - Earth and Planetary Sciences Letters

T2 - Earth and Planetary Sciences Letters

JF - Earth and Planetary Sciences Letters

SN - 0012-821X

ER -