### Abstract

The electrical conductivity of a partial melt is influenced by many factors, including melt conductivity, crystalline conductivity, and melt fraction, each of which is influenced by temperature. We have performed measurements of bulk conductivity as a function of temperature of an Fo_{80}-basalt partial melt between 684° and 1244°C at controlled oxygen fugacity. Melt fraction and composition variations with temperature calculated using MELTS [Ghiorso and Sack, 1995] indicate that the effect on melt conductivity of changing melt composition is balanced by changes in temperature (T). Thus bulk conductivity as a function of T or melt fraction in this system can be calculated assuming a constant melt conductivity. The bulk conductivity is well modeled by simple parallel calculations, by the Hashin-Shtrikman upper bound, or by Archie's law (σ_{partial melt}/σ_{melt} = C_{1}X_{m}^{n}). We estimate apparent values of the Archie's law parameters between 1150° and 1244°C as C_{1} = 0.73±0.02 and n=0.98±0.01. Estimates of the permeability of the system are obtained by using an electrical conductivity-critical scale length relationship and range from ∼10^{-14} to 10^{-18} m^{2}, comparing favorably with previously published values.

Original language | English (US) |
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Article number | 1998JB900111 |

Pages (from-to) | 7055-7065 |

Number of pages | 11 |

Journal | Journal of Geophysical Research: Solid Earth |

Volume | 104 |

Issue number | B4 |

State | Published - Apr 10 1999 |

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### ASJC Scopus subject areas

- Geophysics
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science

### Cite this

*Journal of Geophysical Research: Solid Earth*,

*104*(B4), 7055-7065. [1998JB900111].