Electrical conductivity and dissociation of fluids in crust and mantle

在1 GPa和600℃条件下，测定了H2O-NaCl体系中流体的电导率。这些数据是该系统可用电导率数据的压力范围的两倍以上。开发了一个简单的数值模型，可以预测整个地壳和浅层上地幔中含盐流体的导电性。俯冲带弧前区域电导率的升高可以用不超过1%的含盐流体形成连续的膜或网络来解释。目前的扩展提案要求资助将NaCl-H2O， KCl-H2O， cl - h2o和NaOH-H2O体系的电导率测量扩展到3 GPa和1000˚C。这些数据将对溶解物质的解离常数和上地幔中流体的pH值提供严格的限制，并将允许测试热力学模型的各种预测。此外，这些数据还可以对复杂流体的导电性进行建模，从而可以将热液系统与火山下的岩浆室区分开来，从而有助于火山风险评估。

The electrical conductivity of fluids in the system H2O-NaCl has been measured to 1 GPa and 600 ˚C. These data more than double the pressure range of available conductivity data in this system. A simple numerical model was developed that allows predicting the conductivity of saline fluids in the entire crust and the shallow upper mantle. The elevated conductivity in the forearc region of subduction zones can be explained by not more than 1 % of a saline fluid forming a continuous film or network. The present extension proposal request funding for extending the conductivity measurements in the systems NaCl-H2O, KCl-H2O, HCl-H2O, and NaOH-H2O to 3 GPa and 1000 ˚C. These data would provide firm constraints on dissociation constants of dissolved species and of the pH of fluids in the upper mantle and would allow testing various predictions by thermodynamic models. Moreover, the data would allow modeling the conductivity of complex fluids, which would allow distinguishing hydrothermal systems from magma chambers below volcanoes and therefore aid in volcanic risk assessment.