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Use of a high-precision gravity survey to understand the formation of oceanic crust and the role of melt at the southern Red Sea rift in Afar, Ethiopia

Use of a high-precision gravity survey to understand the formation of oceanic crust and the role of melt at the southern Red Sea rift in Afar, Ethiopia
Use of a high-precision gravity survey to understand the formation of oceanic crust and the role of melt at the southern Red Sea rift in Afar, Ethiopia
The Red Sea arm of the triple junction in northeastern Ethiopia provides an opportunity to investigate rift-forming processes at divergent boundaries. In an attempt to study the subsurface, especially the distribution and role of melt in the rifting process, we carried out a high-precision gravity survey with a mean-square error of 0.011 mgal, assisted by differential global positioning system measurements. The profile is 162 km long and strikes ENE–WSW across the southern part of the Red Sea rift at a latitude of approximately 11.75° N. Modelling of the Bouguer anomaly, constrained by a priori information, showed detailed in-rift variations in the crustal structure and the distribution of melt beneath the rift axis. Our interpretation suggested that the process of continental break-up is governed by crustal stretching and rifting accompanied by the emplacement of melt into the lower crust above a lower density upper mantle. In addition, we interpreted the thickness of the crust beneath this part of the rift axis to be 25 km. The subsurface distribution of density beneath the profile shows that the south-central part of the Red Sea rift has modified thinned crust, intruded by high-density material, which resembles the crust formed during seafloor spreading.
0305-8719
165-180
Lewi, E.
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Keir, D.
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Birhanu, Y.
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Blundy, J.
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Stuart, G.
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Wright, T.
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Calais, E.
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Wright, T.J.
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Ayele, A.
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Ferguson, D.J.
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Kidane, T.
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Vye-Brown, C.
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Lewi, E.
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Keir, D.
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Birhanu, Y.
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Blundy, J.
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Stuart, G.
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Wright, T.
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Calais, E.
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Wright, T.J.
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Ayele, A.
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Ferguson, D.J.
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Kidane, T.
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Vye-Brown, C.
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Lewi, E., Keir, D., Birhanu, Y., Blundy, J., Stuart, G., Wright, T. and Calais, E. , Wright, T.J., Ayele, A., Ferguson, D.J., Kidane, T. and Vye-Brown, C. (eds.) (2015) Use of a high-precision gravity survey to understand the formation of oceanic crust and the role of melt at the southern Red Sea rift in Afar, Ethiopia. Geological Society London Special Publications, 420, 165-180. (doi:10.1144/SP420.13).

Record type: Article

Abstract

The Red Sea arm of the triple junction in northeastern Ethiopia provides an opportunity to investigate rift-forming processes at divergent boundaries. In an attempt to study the subsurface, especially the distribution and role of melt in the rifting process, we carried out a high-precision gravity survey with a mean-square error of 0.011 mgal, assisted by differential global positioning system measurements. The profile is 162 km long and strikes ENE–WSW across the southern part of the Red Sea rift at a latitude of approximately 11.75° N. Modelling of the Bouguer anomaly, constrained by a priori information, showed detailed in-rift variations in the crustal structure and the distribution of melt beneath the rift axis. Our interpretation suggested that the process of continental break-up is governed by crustal stretching and rifting accompanied by the emplacement of melt into the lower crust above a lower density upper mantle. In addition, we interpreted the thickness of the crust beneath this part of the rift axis to be 25 km. The subsurface distribution of density beneath the profile shows that the south-central part of the Red Sea rift has modified thinned crust, intruded by high-density material, which resembles the crust formed during seafloor spreading.

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Published date: 16 December 2015
Organisations: Geology & Geophysics

Identifiers

Local EPrints ID: 385388
URI: http://eprints.soton.ac.uk/id/eprint/385388
ISSN: 0305-8719
PURE UUID: 48091395-0719-4577-bc6b-dcf7ad90fe57
ORCID for D. Keir: ORCID iD orcid.org/0000-0001-8787-8446

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Date deposited: 04 Jan 2016 09:52
Last modified: 15 Mar 2024 03:38

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Contributors

Author: E. Lewi
Author: D. Keir ORCID iD
Author: Y. Birhanu
Author: J. Blundy
Author: G. Stuart
Author: T. Wright
Author: E. Calais
Editor: T.J. Wright
Editor: A. Ayele
Editor: D.J. Ferguson
Editor: T. Kidane
Editor: C. Vye-Brown

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