Electrical conductivity of minerals is sensitive to temperature and defect chemistry (such as the concentration of hydrogen-related defects), but less sensitive to major element chemistry or pressure. Consequently, a comparison of geophysically inferred electrical conductivity with laboratory data will provide important constraints on temperature and water content. However, experimental studies on the role of hydrogen-related defects on electrical conductivity are challenging and very few data are available to provide a basis for such studies. To achieve such a goal, the PI and his colleagues have recently determined the relation between electrical conductivity and water content in wadsleyite and ringwoodite. However, such relationship has not been determined experimentally for another important mineral, majorite garnet, and consequently, the relationship between water content and electrical conductivity in the transition zone is uncertain. In this project, an experimental study on the role of hydrogen-related defects in the electrical conductivity in majorite will be conducted through high-pressure, temperature experiments. The results will provide a solid basis for inferring water (hydrogen) content and temperature in Earth's transition zone.
