Fault-controlled hydration of the upper mantle during continental rifting

Bayrakci, G., Minshull, T. A., Sawyer, D. S., Reston, Timothy J., Klaeschen, Dirk, Papenberg, Cord, Ranero, Cesar, Bull, J. M., Davy, R. G., Shillington, D. J., Perez-Gussinye, M. and Morgan, J. K. (2016) Fault-controlled hydration of the upper mantle during continental rifting Nature Geoscience, 9 (5). pp. 384-388. DOI 10.1038/ngeo2671.

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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.

Document Type: Article
Additional Information: WOS:000375274800017
Keywords: Geodynamics, Hydrogeology, Seismology, Tectonics, RV Poseidon, POS453, POS458, RV Marcus Langseth, MGL1307
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
DOI etc.: 10.1038/ngeo2671
ISSN: 1752-0894
Related URLs:
Expeditions/Models:
Date Deposited: 11 Mar 2016 09:52
Last Modified: 03 May 2017 08:33
URI: http://eprints.uni-kiel.de/id/eprint/31811

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