Preprints
https://doi.org/10.5194/egusphere-2023-345
https://doi.org/10.5194/egusphere-2023-345
21 Mar 2023
 | 21 Mar 2023

Electrical conductivity of anhydrous and hydrous gabbroic melt under high temperature and high pressure: Implications for the high conductivity anomalies in the region of mid‒ocean ridge

Mengqi Wang, Lidong Dai, Haiying Hu, Ziming Hu, Chenxin Jing, Chuanyu Yin, Song Luo, and Jinhua Lai

Abstract. The electrical conductivity of gabbroic melt with four different water contents (i.e. 0, 2.59 wt%, 5.92 wt% and 8.32 wt%) was measured at temperatures of 873–1373 K and pressures of 1.0–3.0 GPa using YJ–3000t multi‒anvil high−pressure apparatus and Solartron‒1260 impedance spectroscopy analyzer. At a fixed water content of 2.59 wt%, the electrical conductivity of the sample slightly decreased with increasing pressure at the temperature range of 873‒1373 K, and its corresponding activation energy and activation volume were determined as 0.87 ± 0.04 eV and ‒1.98 ± 0.02 cm3 mole–1, respectively. Under the certain conditions of 873‒1373 K and 1.0 GPa, the electrical conductivity of the gabbroic melts tends to gradually increase as the rise of water content from 0 to 8.32 wt%, and the activation enthalpy decreases from 0.93 eV to 0.63 eV, accordingly. Furthermore, the functional relation models for the electrical conductivity of gabbroic melts with the variations of temperature, pressure and water content were constructed at high‒temperature and high‒pressure conditions, respectively. In addition, the dependence relation of the electrical conductivity of melts with the degree of depolymerization was explored under conditions of four different water contents, 1373 K and 1.0 GPa, and three previously available reported results on those of representative calc‒alkaline igneous rock melts (i.e. dacitic melt, basaltic melt and andesitic melt) were detailedly compared. In comprehensive combination with our presently acquired electrical conductivity data of gabbroic melt with four different water contents and the available data of polycrystalline olivine, the electrical conductivity of gabbroic melt‒olivine system on the variation of volume percentage of anhydrous and hydrous melts was successfully constructed by virtue of the typical Hashin–Shtrikman upper bound model. In light of the electrical conductivity of gabbroic melt‒olivine system with the previous MT results, we find that the anhydrous and hydrous gabbroic melts can be employed to reasonably interpret the high conductivity anomalies in the Mohns ridge of the Arctic Ocean.

Mengqi Wang et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-345', Anonymous Referee #1, 17 Apr 2023
    • AC1: 'Reply on RC1', Lidong Dai, 09 May 2023
  • RC2: 'Comment on egusphere-2023-345', Anonymous Referee #2, 21 Apr 2023
    • AC2: 'Reply on RC2', Lidong Dai, 09 May 2023

Mengqi Wang et al.

Mengqi Wang et al.

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Short summary
It is first time that the electrical conductivity of gabbroic melt was performed at high temperature and high pressure. The dependence of electrical conductivity on degree of depolymerization was also explored. Electrical conductivity of gabbroic melts can be employed to reasonably interpret the high conductivity anomalies in the Mohns ridge of the Arctic Ocean. In short, it is widespread interests to the potential readers of high-pressure rock physics, solid geophysics and deep Earth science.