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Fault-controlled hydration of the upper mantle during continental rifting

Fault-controlled hydration of the upper mantle during continental rifting
Fault-controlled hydration of the upper mantle during continental rifting
Water and carbon are transferred from the ocean to the mantle in a process that alters mantle peridotite to create serpentinite and supports diverse ecosystems1. Serpentinized mantle rocks are found beneath the sea floor at slow- to ultraslow-spreading mid-ocean ridges1 and are thought to be present at about half the world’s rifted margins2, 3. Serpentinite is also inferred to exist in the downgoing plate at subduction zones4, where it may trigger arc magmatism or hydrate the deep Earth. Water is thought to reach the mantle via active faults3, 4. Here we show that serpentinization at the rifted continental margin offshore from western Spain was probably initiated when the whole crust cooled to become brittle and deformation was focused along large normal faults. We use seismic tomography to image the three-dimensional distribution of serpentinization in the mantle and find that the local volume of serpentinite beneath thinned, brittle crust is related to the amount of displacement along each fault. This implies that sea water reaches the mantle only when the faults are active. We estimate the fluid flux along the faults and find it is comparable to that inferred for mid-ocean ridge hydrothermal systems. We conclude that brittle processes in the crust may ultimately control the global flux of sea water into the Earth.
1752-0894
384-388
Bayrakci, G.
e0b89aa5-d514-4ecb-91b1-8ed8bd472eda
Minshull, T.A.
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Sawyer, D.S.
f827777a-6b45-44d2-a239-3b36fb7ce04a
Reston, T.J.
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Klaeschen, D.
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Papenberg, C.
85928afb-f9b7-4cfe-8fd8-3a89b65d7916
Ranero, C.
d78b6075-55b5-4d77-bfd8-dbda32b19bf8
Bull, J.M.
974037fd-544b-458f-98cc-ce8eca89e3c8
Davy, R.G.
27b2af87-7c07-429e-94c6-5b66e65b5790
Shillington, D.J.
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Perez-Gussinye, M.
da2b79c0-5227-4755-a38b-4b0a18543bfb
Morgan, K.J.
292e6e0d-dd39-4e06-a4a5-e50f5b107a65
Bayrakci, G.
e0b89aa5-d514-4ecb-91b1-8ed8bd472eda
Minshull, T.A.
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Sawyer, D.S.
f827777a-6b45-44d2-a239-3b36fb7ce04a
Reston, T.J.
0ba75307-667f-4f0e-b4fd-42f80a34b4f7
Klaeschen, D.
71af4fb3-19b5-4991-a4d2-944927a46504
Papenberg, C.
85928afb-f9b7-4cfe-8fd8-3a89b65d7916
Ranero, C.
d78b6075-55b5-4d77-bfd8-dbda32b19bf8
Bull, J.M.
974037fd-544b-458f-98cc-ce8eca89e3c8
Davy, R.G.
27b2af87-7c07-429e-94c6-5b66e65b5790
Shillington, D.J.
26369a97-61ca-4ab9-be81-7f817aa87c68
Perez-Gussinye, M.
da2b79c0-5227-4755-a38b-4b0a18543bfb
Morgan, K.J.
292e6e0d-dd39-4e06-a4a5-e50f5b107a65

Bayrakci, G., Minshull, T.A., Sawyer, D.S., Reston, T.J., Klaeschen, D., Papenberg, C., Ranero, C., Bull, J.M., Davy, R.G., Shillington, D.J., Perez-Gussinye, M. and Morgan, K.J. (2016) Fault-controlled hydration of the upper mantle during continental rifting. Nature Geoscience, 9, 384-388. (doi:10.1038/ngeo2671).

Record type: Article

Abstract

Water and carbon are transferred from the ocean to the mantle in a process that alters mantle peridotite to create serpentinite and supports diverse ecosystems1. Serpentinized mantle rocks are found beneath the sea floor at slow- to ultraslow-spreading mid-ocean ridges1 and are thought to be present at about half the world’s rifted margins2, 3. Serpentinite is also inferred to exist in the downgoing plate at subduction zones4, where it may trigger arc magmatism or hydrate the deep Earth. Water is thought to reach the mantle via active faults3, 4. Here we show that serpentinization at the rifted continental margin offshore from western Spain was probably initiated when the whole crust cooled to become brittle and deformation was focused along large normal faults. We use seismic tomography to image the three-dimensional distribution of serpentinization in the mantle and find that the local volume of serpentinite beneath thinned, brittle crust is related to the amount of displacement along each fault. This implies that sea water reaches the mantle only when the faults are active. We estimate the fluid flux along the faults and find it is comparable to that inferred for mid-ocean ridge hydrothermal systems. We conclude that brittle processes in the crust may ultimately control the global flux of sea water into the Earth.

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More information

Accepted/In Press date: 5 February 2016
e-pub ahead of print date: 7 March 2016
Published date: 2016
Organisations: Geology & Geophysics

Identifiers

Local EPrints ID: 388558
URI: https://eprints.soton.ac.uk/id/eprint/388558
ISSN: 1752-0894
PURE UUID: d5e485c1-3db3-4a7d-b7f4-adc8c074050c
ORCID for T.A. Minshull: ORCID iD orcid.org/0000-0002-8202-1379

Catalogue record

Date deposited: 29 Feb 2016 15:28
Last modified: 20 Jul 2019 06:04

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