Properties of Rocks and Minerals – The Electrical Conductivity of Rocks, Minerals, and the Earth

Tyburczy, J.A.

doi:10.1016/b978-044452748-6.00050-x

Cited by 12 publications

(9 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Knowledge of the electrical structure of Mercury's interior has the potential to place constraints on its mineralogy and thermal state because of the high sensitivity of electrical conductivity to temperature and chemistry (e.g., Pommier, ; Tyburczy & Du Frane, ). The electrical and magnetic observations from the MESSENGER mission have been used to constrain an electrical profile of the interior structure of the planet (e.g., Anderson et al, ; Verhoeven et al, ).…”

Section: Discussionmentioning

confidence: 99%

Electrical Investigation of Metal‐Olivine Systems and Application to the Deep Interior of Mercury

Zhang

Pommier

2017

JGR Planets

View full text Add to dashboard Cite

We report electrical conductivity measurements on metal‐olivine systems at about 5 and 6 GPa and up to 1,675°C in order to investigate the electrical properties of core‐mantle boundary (CMB) systems. Electrical experiments were conducted in the multianvil apparatus using the impedance spectroscopy technique. The samples are composed of one metal layer (Fe, FeS, FeSi2, or Fe‐Ni‐S‐Si) and one polycrystalline olivine layer, with the metal:olivine ratio ranging from 1:0.7 to 1:9.2. For all samples, we observe that the bulk electrical conductivity increases with temperature from 10−2.5 to 101.8 S/m, which is higher than the conductivity of polycrystalline olivine but lower than the conductivity of the pure metal phase at similar conditions. In some experiments, a conductivity jump is observed at the temperature corresponding to the melting temperature of the metallic phase. Both the metal:olivine ratio and the metal phase geometry control the electrical conductivity of the two‐layer samples. By combining electrical results, textural analyses of the samples, and previous studies of the structure and composition of Mercury's interior, we propose an electrical profile of the deep interior of the planet that accounts for a layered CMB‐outer core structure. The electrical model agrees with existing conductivity estimates of Mercury's lower mantle and CMB using magnetic observations and thermodynamic calculations, and thus, supports the hypothesis of a layered CMB‐outermost core structure in the present‐day interior of Mercury. We propose that the layered CMB‐outer core structure is possibly electrically insulating, which may influence the planet's structure and cooling history.

show abstract

Section: Discussionmentioning

confidence: 99%

Electrical Investigation of Metal‐Olivine Systems and Application to the Deep Interior of Mercury

Zhang

Pommier

2017

JGR Planets

View full text Add to dashboard Cite

show abstract

“…Next consider the controls on electrical conductivity in silicates (see Tyburczy [] and Yoshino [] for reviews). Mobile point defects due to impurity substitution determine the electrical conductivity of Earth's mantle.…”

Section: Methodsmentioning

confidence: 99%

Geophysical constraints on the lunar Procellarum KREEP Terrane

Grimm

2013

JGR Planets

View full text Add to dashboard Cite

[1] The Moon's Procellarum KREEP Terrane (PKT) is distinguished by unique geochemistry and extended volcanic history. Previous thermal-conduction models using enhanced radionuclide abundances in subcrustal potassium, rare earth elements, and phosphorus (KREEP) predicted the existence of a contemporary upper-mantle melt zone as well as heat flow consistent with Apollo measurements. Here I show that such models also predict large gravity or topography anomalies that are not observed. If the topography is suppressed by a rigid lithosphere, it is possible to eliminate the gravity anomaly and still match heat flow by completely fractionating the excess radionuclides into a thin crust. This implies that upper-mantle heat sources for mare volcanism were spatially discontinuous or transient and that radionuclides defining the PKT are not necessarily directly related to mare volcanic sources. However, the mantle temperature of a crustally fractionated PKT is insufficient to match the observed electrical conductivity: globally enhanced mantle heating or a thick megaregolith may be required. Alternatively, upper-mantle enrichment in iron, hydrogen, or aluminum can provide the requisite conductivity. Iron is the most plausible: the derived lower limit to the upper-mantle magnesium number 75-80% is consistent with seismic modeling. Regardless of the specific mechanism for electrical-conductivity enhancement, the overall excellent match to simple thermal-conduction models indicates that the lunar upper mantle is not convecting at present.

show abstract

“…This idea that a very small melt fraction is retained in the asthenosphere is relevant to the interpretation of electrical conductivity measurements in the Earth. Conductivity is determined by the same compositional and microstructural properties as rheological properties but with potentially very different sensitivities [e.g., Tyburczy and du Frane , ]. For example, current controversy exists on the effects of water (hydrogen) on (anisotropic) conductivity in olivine [e.g., Wang et al ., ; Yoshino et al ., ; Yoshino and Katsura , ; Karato , ; Gardés et al ., ], with significant differences in extrapolations to mantle conditions.…”

Section: Is This Unextractable Melt Fraction Detectable?mentioning

confidence: 99%

Questions on the existence, persistence, and mechanical effects of a very small melt fraction in the asthenosphere

Holtzman

2016

Geochem Geophys Geosyst

View full text Add to dashboard Cite

This paper integrates current questions in rock physics on the effects and behavior of very small melt fractions ( ≪1%) in the asthenosphere. In experiment and theory, it has been shown that a very small melt fraction forming a connected network has a large effect on the diffusion creep shear viscosity, as well as in the anelastic behavior. Because small concentrations of volatiles, particularly H2O and CO2, significantly lower the peridotite solidus, a small melt fraction is expected in the asthenosphere. Even with connected networks, permeability will be low and surface tension will generate a strong force resisting complete draining of small melt fractions. The anelastic reduction of shear velocity due to melt could cause a ≥5% shear velocity contrast across the solidus, consistent with the contrast measured on features in the shallow suboceanic upper mantle that are often interpreted as the lithosphere‐asthenosphere boundary.

show abstract

Properties of Rocks and Minerals – The Electrical Conductivity of Rocks, Minerals, and the Earth

Cited by 12 publications

References 49 publications

Electrical Investigation of Metal‐Olivine Systems and Application to the Deep Interior of Mercury

Electrical Investigation of Metal‐Olivine Systems and Application to the Deep Interior of Mercury

Geophysical constraints on the lunar Procellarum KREEP Terrane

Questions on the existence, persistence, and mechanical effects of a very small melt fraction in the asthenosphere

Contact Info

Product

Resources

About