A joint geochemical–geophysical record of time-dependent mantle convection south of Iceland
A joint geochemical–geophysical record of time-dependent mantle convection south of Iceland
The North Atlantic V-Shaped Ridges (VSRs) provide a spatially extensive and clear record of unsteady mantle convective circulation over >40 My>40 My. VSRs are diachronous ridges of thick crust formed with a periodicity of ?5 My?5 My along the Mid Atlantic Ridge, south of Iceland. We present data from a set of dredged basalt samples that shows chemical variation associated with two complete VSR crustal thickness cycles where they intersect the Mid Atlantic Ridge. The new dataset also records chemical variation associated with a VSR crustal thickness cycle along a plate spreading flow-line. Inverse correlations between crustal thickness and both incompatible trace element concentrations and incompatible element ratios such as Nb/Y and La/Sm are observed. Geochemical and crustal thickness observations can be matched using a time-dependent mid-ocean ridge melting model with a basal boundary condition of sinusoidally varying potential temperature. Our observations and models suggest that VSRs are generated when hot patches are carried up the plume stem beneath SE Iceland and spread radially outward within the asthenosphere. These patches are then drawn upward into the melting region when passing beneath the Mid Atlantic Ridge. The geometry of the VSRs and the size of the dynamically supported swell suggest that the Iceland Plume is the strongest plume in the Earth at present, with a volume flux of View the MathML source49±14 km3yr?1.
plume–ridge interaction, plume pulsing, plume flux, Iceland, Reykjanes Ridge, North Atlantic
86-97
Jones, S.M.
41877a43-02a3-4835-bd04-afd7cc2a52d1
Murton, B.J.
9076d07f-a3c1-4f90-a5d5-99b27fe2cb12
Fitton, J.G.
2cea91e8-0de0-46db-8cb0-f244a498c300
White, N.J.
64c70386-b744-4fb5-9be6-3aec85f9a9e2
Maclennan, J.
f4f7e89b-670f-48fd-ad34-376967ff603c
Walters, R.L.
a4bfed3c-2323-4ced-b0f5-72f944dd6eb3
15 January 2014
Jones, S.M.
41877a43-02a3-4835-bd04-afd7cc2a52d1
Murton, B.J.
9076d07f-a3c1-4f90-a5d5-99b27fe2cb12
Fitton, J.G.
2cea91e8-0de0-46db-8cb0-f244a498c300
White, N.J.
64c70386-b744-4fb5-9be6-3aec85f9a9e2
Maclennan, J.
f4f7e89b-670f-48fd-ad34-376967ff603c
Walters, R.L.
a4bfed3c-2323-4ced-b0f5-72f944dd6eb3
Jones, S.M., Murton, B.J., Fitton, J.G., White, N.J., Maclennan, J. and Walters, R.L.
(2014)
A joint geochemical–geophysical record of time-dependent mantle convection south of Iceland.
Earth and Planetary Science Letters, 386, .
(doi:10.1016/j.epsl.2013.09.029).
Abstract
The North Atlantic V-Shaped Ridges (VSRs) provide a spatially extensive and clear record of unsteady mantle convective circulation over >40 My>40 My. VSRs are diachronous ridges of thick crust formed with a periodicity of ?5 My?5 My along the Mid Atlantic Ridge, south of Iceland. We present data from a set of dredged basalt samples that shows chemical variation associated with two complete VSR crustal thickness cycles where they intersect the Mid Atlantic Ridge. The new dataset also records chemical variation associated with a VSR crustal thickness cycle along a plate spreading flow-line. Inverse correlations between crustal thickness and both incompatible trace element concentrations and incompatible element ratios such as Nb/Y and La/Sm are observed. Geochemical and crustal thickness observations can be matched using a time-dependent mid-ocean ridge melting model with a basal boundary condition of sinusoidally varying potential temperature. Our observations and models suggest that VSRs are generated when hot patches are carried up the plume stem beneath SE Iceland and spread radially outward within the asthenosphere. These patches are then drawn upward into the melting region when passing beneath the Mid Atlantic Ridge. The geometry of the VSRs and the size of the dynamically supported swell suggest that the Iceland Plume is the strongest plume in the Earth at present, with a volume flux of View the MathML source49±14 km3yr?1.
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Published date: 15 January 2014
Keywords:
plume–ridge interaction, plume pulsing, plume flux, Iceland, Reykjanes Ridge, North Atlantic
Organisations:
Marine Geoscience
Identifiers
Local EPrints ID: 362055
URI: http://eprints.soton.ac.uk/id/eprint/362055
ISSN: 0012-821X
PURE UUID: a4905fa0-f157-47e8-a342-b163882fb2f5
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Date deposited: 12 Feb 2014 15:00
Last modified: 14 Mar 2024 16:00
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Contributors
Author:
S.M. Jones
Author:
B.J. Murton
Author:
J.G. Fitton
Author:
N.J. White
Author:
J. Maclennan
Author:
R.L. Walters
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