Elastic and electrical properties and permeability of serpentinites from Atlantis Massif, Mid-Atlantic Ridge

Falcon Suarez, Ismael ORCID: https://orcid.org/0000-0001-8576-5165; Bayrakci, Gaye; Minshull, Tim A.; North, Laurence J.; Best, Angus I. ORCID: https://orcid.org/0000-0001-9558-4261; Rouméjon, Stéphane; IODP Expedition 357 Science Party, .. 2017 Elastic and electrical properties and permeability of serpentinites from Atlantis Massif, Mid-Atlantic Ridge. Geophysical Journal International, 211 (2). 686-699. 10.1093/gji/ggx341

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© Publisher 2017 This is the peer reviewed version of the following article: Falcon-Suarez, I., Bayrakci, G., Minshull, T. A., North, L. J., Best, A. I., & Rouméjon, S. (2017). Elastic and electrical properties and permeability of serpentinites from Atlantis Massif, Mid-Atlantic Ridge. Geophysical Journal International, which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
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Abstract/Summary

Serpentinized peridotites co-exist with mafic rocks in a variety of marine environments including subduction zones, continental rifts and mid-ocean ridges. Remote geophysical methods are crucial to distinguish between them and improve the understanding of the tectonic, magmatic and metamorphic history of the oceanic crust. But, serpentinite peridotites exhibit a wide range of physical properties that complicate such a distinction. We analyzed the ultrasonic P- and S-wave velocities (Vp, Vs) and their respective attenuation (Qp−1, Qs−1), electrical resistivity and permeability of four serpentinized peridotite samples from the southern wall of the Atlantis Massif, Mid-Atlantic Ridge, collected during International Ocean Discovery Program (IODP) Expedition 357. The measurements were taken over a range of loading-unloading stress paths (5 - 45 MPa), using ∼1.7 cm length, 5 cm diameter samples horizontally extracted from the original cores drilled on the seafloor. The measured parameters showed variable degrees of stress dependence, but followed similar trends. Vp, Vs, resistivity and permeability show good inter-correlations, while relationships that included Qp−1 and Qs−1 are less clear. Resistivity showed high contrast between highly serpentinized ultramafic matrix (> 50 Ω m) and mechanically/geochemically altered (magmatic/hydrothermal-driven alteration) domains (< 20 Ω m). This information together with the elastic constants (Vp/Vs ratio and bulk moduli) of the samples allowed us to infer useful information about the degree of serpentinization and the alteration state of the rock, contrasted by petrographic analysis. This study shows the potential of combining seismic techniques and controlled source electromagnetic surveys for understanding tectono-magmatic processes and fluid pathways in hydrothermal systems.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1093/gji/ggx341
ISSN:	0956-540X
Date made live:	02 Aug 2017 12:50 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/517458

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1093/gji/ggx341

ISSN:

0956-540X

Date made live:

02 Aug 2017 12:50 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/517458