Electrical conductivity of OH-bearing omphacite and garnet in eclogite: the quantitative dependence on water content

Electrical Conductivity of Omphacite as a Function of Water Content and Implications for High Conductivity Anomalies in the Dabie‐Sulu UHPM Belts and Tibet

“…It is worth noting that the water content exponent of r ~ 1.1 obtained in this study is exactly the same as that in omphacite derived from Liu et al () and in crustal clinopyroxene from Yang et al () while smaller than that ( r = 1.28) in mantle clinopyroxene from Zhao and Yoshino (). The activation enthalpy determined in this study (0.68–0.76 eV in Table ) is smaller than that of Liu et al () (~0.85 eV) and those of mantle clinopyroxene from Zhao and Yoshino () (0.70–1.01 eV). Liu et al () argued that the activation enthalpy is nearly independent of water content.…”

“…The activation enthalpy determined in this study (0.68-0.76 eV in Table 2) is smaller than that of Liu et al (2019) (~0.85 eV) and those of mantle clinopyroxene from Zhao and Yoshino (2016) (0.70-1.01 eV). Liu et al (2019) argued that the activation enthalpy is nearly independent of water content. The present investigation demonstrated that the activation enthalpy slightly decreases with increasing water content (Table 2), which is consistent with observation in mantle clinopyroxene (Zhao & Yoshino, 2016).…”

“…Electrical conductivity of eclogite largely depends on the electrical conductivity of its major minerals and corresponding volume fractions. According to the present experiment, the electrical conductivity of dry omphacite is lower than that of dry garnet measured by Liu et al (2019) at high temperatures (>600 K). The same trend is also observed in hydrous cases (Figure 7).…”

“…ppm for garnet). As shown in Figure 6, the measured conductivities of dry omphacite between this study (3 GPa) and Liu et al (2019) (1 GPa) are nearly identical, suggesting a negligible effect of pressure on conductivity. In addition, Yang and Heidelbach (2012) revealed that the electrical conductivity of clinopyroxene is independent of grain size.…”

Electrical Conductivity of Clinopyroxene‐NaCl‐H2O System at High Temperatures and Pressures: Implications for High‐Conductivity Anomalies in the Deep Crust and Subduction Zone

“…Dry silicate minerals and rocks cannot result in high‐conductivity anomalies in the Earth's interior (Dai et al, 2014, 2016, 2019; Fuji‐ta et al, 2004; Hu et al, 2013; Yang et al, 2012). In contrast, geophysicists have shown that the high‐conductivity anomalies in the Earth's lithosphere can be caused by the presence of water in nominally anhydrous minerals (Dai & Karato, 2014; Karato, 2019; H. Y. Liu et al, 2019; Wang et al, 2006; Yang et al, 2011), interconnected aqueous fluids (Amiguet et al, 2012; X. Z. Guo et al, 2015; Li et al, 2018; Manthilake et al, 2015, 2016; Shimojuku et al, 2014; Sinmyo & Keppler, 2017), partial melting (Freitas et al, 2019; Gaillard, 2005; X. Guo et al, 2018; Laumonier et al, 2015, 2017; Maumus et al, 2005; H. W. Ni et al, 2011), and interconnected secondary high‐conductivity phases (Bagdassarov et al, 2009; Glover et al, 1996; Kawano et al, 2012; Manthilake et al, 2016; Wang et al, 2013; Zhang & Yoshino, 2016).…”