Electrical conductivity of the plagioclase–NaCl–water system and its implication for the high conductivity anomalies in the mid-lower crust of Tibet Plateau

Li, Ping; Guo, Xinzhuan; Chen, Sibo; Wang, Chao; Yang, Junlong; Zhou, Xingfan

doi:10.1007/s00410-018-1442-9

Cited by 17 publications

(37 citation statements)

References 63 publications

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“…Aside from the chemical composition, other available alternative causes for high conductivity anomalies can be considered, such as water in nominally anhydrous minerals (Wang et al, 2006;Yang, 2011;Karato, 2009, 2014a), interconnected saline (or aqueous) fluids (Hashim et al, 2013;Shimojuku et al, 2014;Sinmyo and Keppler, 2017;Guo et al, 2015;Li et al, 2018), partial melting (Wei et al, 2001;Maumus et al, 2005;Gaillard et al, 2008;Ferri et al, 2013;Laumonier et al, 2015Laumonier et al, , 2017Ghosh and Karki, 2017), interconnected secondary high conductivity phases (e.g., FeS, Fe 3 O 4 ; Jones et al, 2005;Bagdassarov et al, 2009;Padilha et al, 2015), dehydration of hydrous minerals (Wang et al, 2012(Wang et al, , 2017Manthilake et al, 2015Manthilake et al, , 2016Hu et al, 2017;Sun et al, 2017a, b;Chen et al, 2018) and graphite films on mineral grain boundaries (Freund, 2003;Pous et al, 2004;Chen et al, 2017). In consideration of the similar formation conduction and geotectonic environments, the Himalaya-Tibetan orogenic system was compared with the Dabie-Sulu UHPM belt and explained high electrical conductivity anomalies.…”

Section: Geophysical Implicationsmentioning

confidence: 99%

Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

Dai

Sun

et al. 2018

Solid Earth

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Abstract. The electrical conductivity of gneiss samples with different chemical compositions (W A = Na 2 O + K 2 O + CaO = 7.12, 7.27 and 7.64 % weight percent) was measured using a complex impedance spectroscopic technique at 623-1073 K and 1.5 GPa and a frequency range of 10 −1 to 10 6 Hz. Simultaneously, a pressure effect on the electrical conductivity was also determined for the W A = 7.12 % gneiss. The results indicated that the gneiss conductivities markedly increase with total alkali and calcium ion content. The sample conductivity and temperature conform to an Arrhenius relationship within a certain temperature range. The influence of pressure on gneiss conductivity is weaker than temperature, although conductivity still increases with pressure. According to various ranges of activation enthalpy (0.35-0.52 and 0.76-0.87 eV) at 1.5 GPa, two main conduction mechanisms are suggested that dominate the electrical conductivity of gneiss: impurity conduction in the lower-temperature region and ionic conduction (charge carriers are K + , Na + and Ca 2+ ) in the higher-temperature region. The electrical conductivity of gneiss with various chemical compositions cannot be used to interpret the high conductivity anomalies in the Dabie-Sulu ultrahigh-pressure metamorphic belt. However, the conductivity-depth profiles for gneiss may provide an important constraint on the interpretation of field magnetotelluric conductivity results in the regional metamorphic belt.

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Section: Geophysical Implicationsmentioning

confidence: 99%

Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

Dai

Sun

et al. 2018

Solid Earth

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“…Recently, Sinmyo and Keppler (2017) measured the electrical conductivity of aqueous NaCl-bearing fluids in an externally heated diamond cell to 1 GPa and 600°C. Moreover, a number of studies investigated the conductivity of two-phase systems, where a fluid is contained in the pore space between mineral grains up to about 1 GPa (Guo et al, 2015;Li et al, 2018;Shimojuku et al, 2012Shimojuku et al, , 2014. However, due to the recrystallization of the mineral grains and associated changes in fluid connectivity and fluid composition, these data are difficult to interpret in terms of pure fluid conductivity (see discussion in Sinmyo & Keppler, 2017).…”

Section: Introductionmentioning

confidence: 99%

Electrical Conductivity of NaCl‐Bearing Aqueous Fluids to 900 °C and 5 GPa

Guo

Keppler

2019

JGR Solid Earth

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The electrical conductivity of aqueous fluids containing 0.01, 0.1, and 1 M NaCl was measured in a piston‐cylinder apparatus up to 900 °C and 5 GPa. The conductivity generally increases with NaCl concentration, while the pressure and temperature effects are more complex. At 1–2 GPa, the effect of temperature on conductivity is small, while at higher pressures, conductivity increases with temperature. Pressure also enhances conductivity, but only above 300–400 °C. This effect may be due to enhanced ion dissociation in response to an increasing dielectric constant. However, at lower temperatures, conductivity decreases with pressure, probably due to an increase in fluid viscosity. The measured conductivities of NaCl‐H2O fluids up to 900 °C and 5 GPa are reproduced (R2 = 0.953) by a numerical model with log σ = −0.919 − 872.5/T + 7.61 log ρ + 0.852 log c + log Λ0, where σ is the conductivity in S/m, T is temperature in K, c is NaCl concentration in wt%, ρ is the density of pure water (in g/cm3) at given pressure and temperature, and Λ0 is the molar conductivity of NaCl in water at infinite dilution (in S·cm2·mol−1), Λ0 = 1,573 − 1,212 ρ + 537,062/T – 208,122,721/T2. We use our data to model the elevated electrical conductivity in the mantle wedge above subducted slabs. We find that due to the strong conductivity enhancement, in most cases less than one volume percent of aqueous fluid with moderate salinity is sufficient to explain the observed conductivity anomalies.

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“…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). Despite multiple interpretations for the high‐conductivity anomalies in the deep Earth, the practical origin in a certain geological environment can be constrained based on the MT and seismic data.…”

Section: Introductionmentioning

confidence: 99%

“…Electrical properties of the albite‐NaCl‐H 2 O, albite‐(quartz)‐H 2 O, quartz‐H 2 O and plagioclase‐NaCl‐H 2 O systems have been researched under crustal pressure and temperature conditions (X. Z. Guo et al, 2015; Li et al, 2018; Shimojuku et al, 2012). It has been proposed that NaCl‐bearing aqueous fluids may affect the high‐conductivity anomalies under the deep crust and subduction zone significantly (H. H. Guo & Keppler, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the fluid fraction and salinity, the major mineral has a moderate influence on the electrical properties of the saline fluid‐bearing rocks (Li et al, 2018) because the bulk conductivity is related closely to the electrical conductivity of the major mineral. The connectivity of the aqueous fluids depends on the mineral species to some extent.…”

Section: Introductionmentioning

confidence: 99%

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

Sun

Dai

et al. 2020

JGR Solid Earth

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Electrical conductivities of the clinopyroxene (Cpx)-NaCl-H 2 O system with various salinities (5, 10, 15, 20, 25 wt%) and fluid fractions (5, 10, 15, 20, 25 vol%) were measured at 1 GPa and 673-973 K. For comparison with electrical properties of the Cpx-NaCl-H 2 O system, the conductivities of dry Cpx, hydrous Cpx, and a Cpx-H 2 O system were researched at the same temperature and pressure. The experimental results included (1) the electrical conductivities of all samples that were associated with Cpx and the temperatures conform to the Arrhenius relationship that is used to fit the activation enthalpy, which decreased with increasing salinity (mass fraction of NaCl in saline fluids) and fluid fraction (volume fraction of saline fluids in the Cpx-NaCl-H 2 O system); (2) at a fixed fluid fraction of 10 vol%, the conductivities of the Cpx-NaCl-H 2 O system increased slightly with an increase in salinity, and the gap between the conductivities of the systems with 5 and 25 wt% saline fluids was approximately 1 order of magnitude;(3) at a fixed salinity of 5 wt%, the conductivity of the Cpx-NaCl-H 2 O system with 25 vol% saline fluids was approximately 1.5 orders of magnitude higher than that of the system with 5 vol% saline fluids. Furthermore, it was proposed that the unusually high conductivities of southern Tibetan Plateau, Dabie Orogen, Grenville province and central New Zealand can be caused by clinopyroxene with interconnected saline fluids with corresponding salinities and fluid fractions.

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Electrical conductivity of the plagioclase–NaCl–water system and its implication for the high conductivity anomalies in the mid-lower crust of Tibet Plateau

Cited by 17 publications

References 63 publications

Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

Electrical Conductivity of NaCl‐Bearing Aqueous Fluids to 900 °C and 5 GPa

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

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Electrical conductivity of the plagioclase–NaCl–water system and its implication for the high conductivity anomalies in the mid-lower crust of Tibet Plateau

Cited by 17 publications

References 63 publications

Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

Electrical Conductivity of NaCl‐Bearing Aqueous Fluids to 900 °C and 5 GPa

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

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