Electrical conductivity of the serpentinised mantle and fluid flow in subduction zones

Reynard, Bruno; Mibe, Kenji; Moortèle, Bertrand Van de

doi:10.1016/j.epsl.2011.05.013

Cited by 103 publications

(121 citation statements)

References 45 publications

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“…Serpentinites have been found to have high resistivities (>1000  m) at high temperature and high pressure conditions, due to dehydration (Popp and Kern, 1993, Reynard et al, 2011, Xie et al, 2002. However, our experiments have been carried out at relatively low PT and the values obtained remain below 100  m, which agree with the data reported by Stesky and Brace (1973) for similar PT conditions and pore fluid electrical conductivity (~0.19  m).…”

Section: Relations Between Geophysical Parameters and Permeabilitysupporting

confidence: 77%

“…However, electrical resistivity depends on the physico-chemical properties of the pore fluid (pressure, temperature and salinity) as well as the solid rock matrix, so inferring lithological variations from resistivity variations may result in misleading interpretations. In addition, very few studies can be found in the literature addressing electrical properties of serpentinite core specimens (Popp andKern, 1993, Stesky andBrace, 1973), and there are only a few analyses using millimetric sized samples (Guo et al, 2011, Reynard et al, 2011, Xie et al, 2002.…”

Section: Introductionmentioning

confidence: 99%

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

Falcón-Suarez¹,

Bayrakci²,

Minshull³

et al. 2017

Geophysical Journal International

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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

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Section: Relations Between Geophysical Parameters and Permeabilitysupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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

Falcón-Suarez¹,

Bayrakci²,

Minshull³

et al. 2017

Geophysical Journal International

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“…High conductivities of the forearc regions require the presence of an interconnected conductive fluid mixed with serpentinized peridotites because highconductivity solids, iron oxides, sulfides, graphite, and metals are likely not sufficiently abundant to form a connective network (Kawano, et al 2012;Reynard, et al 2011). At the low temperatures of the forearc mantle, saline waters are the best candidates for highconductivity fluids in the absence of melting.…”

Section: Magnetotelluricsmentioning

confidence: 99%

“…Silicates, including both nominally anhydrous and hydrous phases such as serpentines, are poor conductors, with a small polaron-type conduction mechanism that results in high temperature dependence, and typical conductivities lower than 10 −3 -10 −4 S.m −1 at temperatures of the forearc (Guo, et al 2011;Reynard, et al 2011). Brucite, a minor component of hydrated ultrabasic rocks, has a slightly higher conductivity, because conductivity occurs mainly by proton exchange (Fujita, et al 2007), but is not abundant enough to explain high conductivity in hydrated ultrabasic rocks.…”

Section: Magnetotelluricsmentioning

confidence: 99%

Mantle hydration and Cl-rich fluids in the subduction forearc

Reynard

2016

Prog. in Earth and Planet. Sci.

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In the forearc region, aqueous fluids are released from the subducting slab at a rate depending on its thermal state. Escaping fluids tend to rise vertically unless they meet permeability barriers such as the deformed plate interface or the Moho of the overriding plate. Channeling of fluids along the plate interface and Moho may result in fluid overpressure in the oceanic crust, precipitation of quartz from fluids, and low Poisson ratio areas associated with tremors. Above the subducting plate, the forearc mantle wedge is the place of intense reactions between dehydration fluids from the subducting slab and ultramafic rocks leading to extensive serpentinization. The plate interface is mechanically decoupled, most likely in relation to serpentinization, thereby isolating the forearc mantle wedge from convection as a cold, potentially serpentinized and buoyant, body. Geophysical studies are unique probes to the interactions between fluids and rocks in the forearc mantle, and experimental constrains on rock properties allow inferring fluid migration and fluid-rock reactions from geophysical data. Seismic velocities reveal a high degree of serpentinization of the forearc mantle in hot subduction zones, and little serpentinization in the coldest subduction zones because the warmer the subduction zone, the higher the amount of water released by dehydration of hydrothermally altered oceanic lithosphere. Interpretation of seismic data from petrophysical constrain is limited by complex effects due to anisotropy that needs to be assessed both in the analysis and interpretation of seismic data. Electrical conductivity increases with increasing fluid content and temperature of the subduction. However, the forearc mantle of Northern Cascadia, the hottest subduction zone where extensive serpentinization was first demonstrated, shows only modest electrical conductivity. Electrical conductivity may vary not only with the thermal state of the subduction zone, but also with time for a given thermal state through variations of fluid salinity. High-Cl fluids produced by serpentinization can mix with the source rocks of the volcanic arc and explain geochemical signatures of primitive magma inclusions. Signature of deep high-Cl fluids was also identified in forearc hot springs. These observations suggest the existence of fluid circulations between the forearc mantle and the hot spring hydrothermal system or the volcanic arc. Such circulations are also evidenced by recent magnetotelluric profiles.

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“…Typical temperature fluctuation during heating was within ±5 K. Alumina was used as an insulator between the electrical resistivity measurement lines and the heater lines. The resistivity of alumina used in this study was sufficiently higher than that of the sample at high pressures and high temperatures (Reynard et al 2011).…”

Section: Methodsmentioning

confidence: 92%

Influence of pressure and temperature on the electrical conductivity of dolomite

Ono

Mibe

2015

Phys Chem Minerals

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Electrical conductivity of the serpentinised mantle and fluid flow in subduction zones

Cited by 103 publications

References 45 publications

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

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

Mantle hydration and Cl-rich fluids in the subduction forearc

Influence of pressure and temperature on the electrical conductivity of dolomite

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