The University of Southampton
University of Southampton Institutional Repository

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

Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction
Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction
The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g. thermal vs. 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.
Mantle Transition Zone, Water, Mantle Upwelling, East Africa
1525-2027
834-846
Thompson, D.A.
17847a69-b34b-4daa-aca8-f62899d0421a
Hammond, J.O.S.
df081c77-2e69-4753-8846-549826d905bb
Kendall, J-M.
9a2eb4fe-eb71-4d9b-955b-b56b790c2bf9
Stuart, G.W.
42655128-f55d-42a7-afd8-7a2fca1c01a3
Helffrich, G.R.
d93912ce-1384-4a64-a66a-9110190dd851
Keir, D.
5616f81f-bf1b-4678-a167-3160b5647c65
Ayele, A.
2a0d90e9-a4be-4484-9301-5c4df46f9407
Goitom, B.
e136980f-049f-47f8-9526-59cc785127db
Thompson, D.A.
17847a69-b34b-4daa-aca8-f62899d0421a
Hammond, J.O.S.
df081c77-2e69-4753-8846-549826d905bb
Kendall, J-M.
9a2eb4fe-eb71-4d9b-955b-b56b790c2bf9
Stuart, G.W.
42655128-f55d-42a7-afd8-7a2fca1c01a3
Helffrich, G.R.
d93912ce-1384-4a64-a66a-9110190dd851
Keir, D.
5616f81f-bf1b-4678-a167-3160b5647c65
Ayele, A.
2a0d90e9-a4be-4484-9301-5c4df46f9407
Goitom, B.
e136980f-049f-47f8-9526-59cc785127db

Thompson, D.A., Hammond, J.O.S., Kendall, J-M., Stuart, G.W., Helffrich, G.R., Keir, D., Ayele, A. and Goitom, B. (2015) Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction. Geochemistry, Geophysics, Geosystems, 16 (3), 834-846. (doi:10.1002/2014GC005648).

Record type: Article

Abstract

The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g. thermal vs. 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.

Text
ggge20691.pdf - Version of Record
Available under License Creative Commons Attribution.
Download (5MB)

More information

Accepted/In Press date: 1 March 2015
e-pub ahead of print date: 24 March 2015
Published date: March 2015
Keywords: Mantle Transition Zone, Water, Mantle Upwelling, East Africa
Organisations: Geology & Geophysics

Identifiers

Local EPrints ID: 374813
URI: http://eprints.soton.ac.uk/id/eprint/374813
ISSN: 1525-2027
PURE UUID: 8a2376f8-f19b-4d62-b33a-b8bd56e3ed6f
ORCID for D. Keir: ORCID iD orcid.org/0000-0001-8787-8446

Catalogue record

Date deposited: 03 Mar 2015 13:51
Last modified: 15 Mar 2024 03:38

Export record

Altmetrics

Contributors

Author: D.A. Thompson
Author: J.O.S. Hammond
Author: J-M. Kendall
Author: G.W. Stuart
Author: G.R. Helffrich
Author: D. Keir ORCID iD
Author: A. Ayele
Author: B. Goitom

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×