Prediction of silicate melt viscosity from electrical conductivity: A model and its geophysical implications

Pommier, Anne; Evans, Robert; Key, Kerry; Tyburczy, J. A.; Mackwell, S. J.; Elsenbeck, Jimmy

doi:10.1002/ggge.20103

Cited by 19 publications

(29 citation statements)

References 38 publications

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“…Because the self-diffusion coefficients of the ions in the melt increase with the temperature, the viscosity is negatively correlated with the temperature when the electrical conductivity is positively correlated to it. Therefore, one recovers the well-known result that, at a given pressure, and are negatively correlated with each other (Pfeiffer, 1998;Harris, 2010;Pommier et al, 2013). However, the quantification of this correlation with the help of an analytical expression is difficult for silicate melts because the viscosity is mainly governed by the least mobile ions (network formers) whereas the electrical conductivity is governed by the most mobile ones (network modifiers).…”

Section: Discussionmentioning

confidence: 68%

“…The simulation data give some clues concerning the relationship between viscosity and electrical conductivity, a relationship which, among other things, can be useful to improve the interpretation of magnetotelluric data (Pommier et al, 2013). Because the self-diffusion coefficients of the ions in the melt increase with the temperature, the viscosity is negatively correlated with the temperature when the electrical conductivity is positively correlated to it.…”

Section: Discussionmentioning

confidence: 99%

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Properties of magmatic liquids by molecular dynamics simulation: The example of a MORB melt

et al. 2017

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International audienceA new atom-atom interaction potential is introduced for describing by classical molecular dynamics (MD) simulation the physical properties of natural silicate melts. The equation of state, the microscopic structure, the viscosity, the electrical conductivity, and the self-diffusion coefficients of ions in a mid-oceanic ridge basalt (MORB) melt are evaluated by MD over a large range of temperature and pressure (1673-3273 K and 0-60 GPa). A detailed comparison with experimental data shows that the model reproduces the thermodynamic, structural and transport properties of a MORB with an unprecedented accuracy. In particular, it is shown that the MORB melt crystallizes at lower mantle conditions into a perovskite phase whose the equation of state (EOS) is compatible with those proposed in the experimental literature. Moreover, in accordance with experimental findings, the simulation predicts not only that the MORB viscosity exhibits a (slight) minimum with the pressure, but also that the viscosity at high temperature remains very low (<100 mPa.s for T > 2273 K) even at high pressure (up to 40 GPa). However the evolution of the electrical conductivity with temperature and pressure is not always the symmetrical of that of the viscosity. In fact, the relationship between viscosity and electrical conductivity shows a crossover at around 2073 K

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Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Properties of magmatic liquids by molecular dynamics simulation: The example of a MORB melt

et al. 2017

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“…See text for details. Optical Basicity calculated using Pommier et al []. Pr et al: Presnall et al []; WW: Waff and Weill []; RM: Rai and Manghnani []; K et al: Kawahara et al []; TW: Tyburczy and Waff [, ]; LT: Li and Tomozawa []; S et al: Simonnet et al []; G: Gaillard []; P et al: Pommier et al [, ]; N et al: Ni et al [, ]; No et al: Noritake et al [].…”

Section: Electrical Conductivity Of Peridotites During Partial Meltinmentioning

confidence: 99%

“…In silicate melts, network modifying cations (e.g., Mg 2+ , Ca 2+ , Fe 2+ , Na + , K + , and H + ) are considered as bases (electron donors) and network forming cations (Si 4+ and Al 3+ ) as acids (electron receivers). The interested reader is referred to Pommier et al [] for details regarding the Optical Basicity calculation for silicate melts and its effect on electrical conductivity.…”

Section: Electrical Conductivity Of Peridotites During Partial Meltinmentioning

confidence: 99%

“…For instance, a low degree of melting of fertile peridotite (<5%) at 1 GPa produces melts whose bulk chemistry is significantly different from the composition of typical basaltic melts [e.g., Baker and Stolper , ; Baker et al , ]. Because electrical conductivity is sensitive to melt chemical composition [ Roberts and Tyburczy , ; Gaillard and Iacono Marziano , ; Pommier et al , , ], it is expected that the electrical response of molten silicates from low‐degree melting should differ from the conductivity of basaltic melt at similar pressure and temperature, hence influencing the estimation of melt fraction. Since isolated pockets of melt do not significantly influence bulk conductivity, the effect of melt composition on bulk conductivity is especially relevant for contexts of interconnected melt, which can occur at very low melt fraction [e.g., Kohlstedt , ].…”

Section: Introductionmentioning

confidence: 99%

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Petrology‐based modeling of mantle melt electrical conductivity and joint interpretation of electromagnetic and seismic results

Pommier

Garnero

2014

JGR Solid Earth

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The presence of melt in the Earth's interior depends on the thermal state, bulk chemistry, and dynamics. Therefore, the investigation of the physical and chemical properties of melt is a probe of the planet's structure, dynamics, and potentially evolution. Here we explore melt properties by interpreting geophysical data sets sensitive to the presence of melt (electromagnetic and seismic) with considerations of petrology and, in particular, peridotite partial melting. We present a petrology-based model of the electrical conductivity of fertile and depleted peridotites during partial melting. Seismic and magnetotelluric (MT) studies do not necessarily agree on melt fraction estimates, a possible explanation being the assumptions made about melt chemistry as part of MT data interpretation. Melt fraction estimates from electrical anomalies usually assume a basaltic melt phase, whereas petrological knowledge suggests that the first liquids produced have a different chemistry, and thus a different conductivity. Our results show that melts produced by low-degree peridotite melting (< 15 vol %) are up to 5 times more conductive than basaltic liquids. Such conductive melts significantly affect bulk rock conductivity. Application of our electrical model to magnetotelluric results suggests melt fractions that are in good agreement with seismic estimates. With the aim of a simultaneous interpretation of electrical and seismic data, we combine our electrical results with seismic velocity considerations in a joint model of partial melting. Field electrical and seismic anomalies can be explained by~1 vol % melt beneath Hawaii and~1-8 vol % melt beneath the Afar Ridge.

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Constraints on the evolution of crustal flow beneath Northern Tibet

Pape

Jones

Unsworth

et al. 2015

Geochem Geophys Geosyst

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Crustal flow is an important tectonic process active in continent‐continent collisions and which may be significant in the development of convergent plate boundaries. In this study, the results from multidimensional electrical conductivity modeling have been combined with laboratory studies of the rheology of partially molten rocks to characterize the rheological behavior of the middle‐to‐lower crust of both the Songpan‐Ganzi and Kunlun terranes in the northern Tibetan Plateau. Two different methods are adopted to develop constraints on melt fraction, temperature, and crustal flow velocity in the study area. The estimates of these parameters are then used to evaluate whether crustal flow can occur on the northern margin of the Tibetan plateau. In the Songpan‐Ganzi crust, all conditions are satisfied for topography‐driven channel flow to be dominant, with partial melt not being required for flow at temperature above 1000°C. Further north, the Kunlun fault defines the southern boundary of a transition zone between the Tibetan plateau and the Qaidam basin. Constrained by the estimated melt fractions, it is shown that channel injection across the fault requires temperatures close to 900°C. The composition of igneous rocks found at the surface confirm those conditions are met for the southern Kunlun ranges. To the north, the Qaidam basin is characterized by colder crust that may reflect an earlier stage in the channel injection process. In the study area, at least 10% of the eastward directed Tibetan crustal flow could be deflected northward across the Kunlun Fault and injected into the transition zone defining the northern margin of the Tibetan plateau.

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Prediction of silicate melt viscosity from electrical conductivity: A model and its geophysical implications

Cited by 19 publications

References 38 publications

Properties of magmatic liquids by molecular dynamics simulation: The example of a MORB melt

Properties of magmatic liquids by molecular dynamics simulation: The example of a MORB melt

Petrology‐based modeling of mantle melt electrical conductivity and joint interpretation of electromagnetic and seismic results

Constraints on the evolution of crustal flow beneath Northern Tibet

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