Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction

D. A. Thompson (Corresponding Author), J.O.S. Hammond, J-M Kendall, G.W. Stuart, G. R. Helffrich, D. Keir, A. Ayele, B. Goitom

Research output: Contribution to journalArticle

19 Citations (Scopus)
4 Downloads (Pure)

Abstract

The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g., thermal versus compositional buoyancy) are key to our understanding of whole mantle convective processes. We address these issues through a receiver function study on new seismic data from recent deployments located on the Afar Triple Junction, a location associated with deep mantle upwelling. The detailed images of upper mantle and mantle transition zone structure illuminate features that give insights into the nature of upwelling from the deep Earth. A seismic low-velocity layer directly above the mantle transition zone, interpreted as a stable melt layer, along with a prominent 520 km discontinuity suggest the presence of a hydrous upwelling. A relatively uniform transition zone thickness across the region suggests a weak thermal anomaly (<100 K) may be present and that upwelling must be at least partly driven by compositional buoyancy. The results suggest that the lower mantle is a source of volatile rich, chemically distinct upwellings that influence the structure of the upper mantle, and potentially the chemistry of surface lavas.
Original languageEnglish
Pages (from-to)834-346
Number of pages13
JournalGeochemistry, Geophysics, Geosystems
Volume16
Issue number3
Early online date24 Mar 2015
DOIs
Publication statusPublished - Mar 2015

Fingerprint

triple junction
upwelling water
Buoyancy
transition zone
upwelling
Earth mantle
mantle
upper mantle
Earth (planet)
buoyancy
lower mantle
temperature anomaly
seismic data
discontinuity
Hot Temperature
melt
low speed
receivers
chemistry
anomalies

Keywords

  • mantle transition zone
  • water
  • mantle upwelling
  • East Africa

Cite this

Thompson, D. A., Hammond, J. O. S., Kendall, J-M., Stuart, G. W., Helffrich, G. R., Keir, D., ... Goitom, B. (2015). Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction. Geochemistry, Geophysics, Geosystems , 16(3), 834-346. https://doi.org/10.1002/2014GC005648

Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction. / Thompson, D. A. (Corresponding Author); Hammond, J.O.S.; Kendall, J-M; Stuart, G.W.; Helffrich, G. R.; Keir, D.; Ayele, A.; Goitom, B.

In: Geochemistry, Geophysics, Geosystems , Vol. 16, No. 3, 03.2015, p. 834-346.

Research output: Contribution to journalArticle

Thompson, DA, Hammond, JOS, Kendall, J-M, Stuart, GW, Helffrich, GR, Keir, D, Ayele, A & Goitom, B 2015, 'Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction', Geochemistry, Geophysics, Geosystems , vol. 16, no. 3, pp. 834-346. https://doi.org/10.1002/2014GC005648
Thompson DA, Hammond JOS, Kendall J-M, Stuart GW, Helffrich GR, Keir D et al. Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction. Geochemistry, Geophysics, Geosystems . 2015 Mar;16(3):834-346. https://doi.org/10.1002/2014GC005648
Thompson, D. A. ; Hammond, J.O.S. ; Kendall, J-M ; Stuart, G.W. ; Helffrich, G. R. ; Keir, D. ; Ayele, A. ; Goitom, B. / Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction. In: Geochemistry, Geophysics, Geosystems . 2015 ; Vol. 16, No. 3. pp. 834-346.
@article{908f35df98ed40ac8f88b4db40506ac5,
title = "Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction",
abstract = "The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g., thermal versus compositional buoyancy) are key to our understanding of whole mantle convective processes. We address these issues through a receiver function study on new seismic data from recent deployments located on the Afar Triple Junction, a location associated with deep mantle upwelling. The detailed images of upper mantle and mantle transition zone structure illuminate features that give insights into the nature of upwelling from the deep Earth. A seismic low-velocity layer directly above the mantle transition zone, interpreted as a stable melt layer, along with a prominent 520 km discontinuity suggest the presence of a hydrous upwelling. A relatively uniform transition zone thickness across the region suggests a weak thermal anomaly (<100 K) may be present and that upwelling must be at least partly driven by compositional buoyancy. The results suggest that the lower mantle is a source of volatile rich, chemically distinct upwellings that influence the structure of the upper mantle, and potentially the chemistry of surface lavas.",
keywords = "mantle transition zone, water, mantle upwelling, East Africa",
author = "Thompson, {D. A.} and J.O.S. Hammond and J-M Kendall and G.W. Stuart and Helffrich, {G. R.} and D. Keir and A. Ayele and B. Goitom",
year = "2015",
month = "3",
doi = "10.1002/2014GC005648",
language = "English",
volume = "16",
pages = "834--346",
journal = "Geochemistry, Geophysics, Geosystems",
issn = "1525-2027",
publisher = "American Geophysical Union",
number = "3",

}

TY - JOUR

T1 - Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction

AU - Thompson, D. A.

AU - Hammond, J.O.S.

AU - Kendall, J-M

AU - Stuart, G.W.

AU - Helffrich, G. R.

AU - Keir, D.

AU - Ayele, A.

AU - Goitom, B.

PY - 2015/3

Y1 - 2015/3

N2 - The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g., thermal versus compositional buoyancy) are key to our understanding of whole mantle convective processes. We address these issues through a receiver function study on new seismic data from recent deployments located on the Afar Triple Junction, a location associated with deep mantle upwelling. The detailed images of upper mantle and mantle transition zone structure illuminate features that give insights into the nature of upwelling from the deep Earth. A seismic low-velocity layer directly above the mantle transition zone, interpreted as a stable melt layer, along with a prominent 520 km discontinuity suggest the presence of a hydrous upwelling. A relatively uniform transition zone thickness across the region suggests a weak thermal anomaly (<100 K) may be present and that upwelling must be at least partly driven by compositional buoyancy. The results suggest that the lower mantle is a source of volatile rich, chemically distinct upwellings that influence the structure of the upper mantle, and potentially the chemistry of surface lavas.

AB - The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g., thermal versus compositional buoyancy) are key to our understanding of whole mantle convective processes. We address these issues through a receiver function study on new seismic data from recent deployments located on the Afar Triple Junction, a location associated with deep mantle upwelling. The detailed images of upper mantle and mantle transition zone structure illuminate features that give insights into the nature of upwelling from the deep Earth. A seismic low-velocity layer directly above the mantle transition zone, interpreted as a stable melt layer, along with a prominent 520 km discontinuity suggest the presence of a hydrous upwelling. A relatively uniform transition zone thickness across the region suggests a weak thermal anomaly (<100 K) may be present and that upwelling must be at least partly driven by compositional buoyancy. The results suggest that the lower mantle is a source of volatile rich, chemically distinct upwellings that influence the structure of the upper mantle, and potentially the chemistry of surface lavas.

KW - mantle transition zone

KW - water

KW - mantle upwelling

KW - East Africa

U2 - 10.1002/2014GC005648

DO - 10.1002/2014GC005648

M3 - Article

VL - 16

SP - 834

EP - 346

JO - Geochemistry, Geophysics, Geosystems

JF - Geochemistry, Geophysics, Geosystems

SN - 1525-2027

IS - 3

ER -