Abstract
Electrical conductivity, via the geophysical method of magnetotellurics (MT), gives us amazing insight into the crust and mantle zone. However,
the conductivity of many minerals is poorly constrained inhibiting the interpretation of these MT data. In the work presented here we build on the electrical conductivity (EC) measurements of Amulele et al., (2018), by carrying out EC measurements under crustal hydration melting conditions at 1 GPa on a single crystal of labradorite. Hydration and melting were achieved by enclosing the sample in a talc sleeve (see Figure) and carrying out the conductivity measurements above the dehydration temperature of talc (800°C), which is also within the temperature region in which, most alkaline feldspars will being to melt at ambient pressure. Electrical conductivity measurements were obtained using the impedance spectroscopy method at temperatures between 300°C and 1100°C and the conductivity behaviour in labradorite determined upon melting. At least 800 ppm wt. uptake of water was measured in the crystal at saturated water conditions. The electrical conductivity in single crystal labradorite has been analysed using the Hashin and Shtrikman mixing model to determine the melt fraction and hydrous melt conductivity in the mineral. A preliminary version of this work was presented at GSA Cordilleran Section meeting July, 2017.
the conductivity of many minerals is poorly constrained inhibiting the interpretation of these MT data. In the work presented here we build on the electrical conductivity (EC) measurements of Amulele et al., (2018), by carrying out EC measurements under crustal hydration melting conditions at 1 GPa on a single crystal of labradorite. Hydration and melting were achieved by enclosing the sample in a talc sleeve (see Figure) and carrying out the conductivity measurements above the dehydration temperature of talc (800°C), which is also within the temperature region in which, most alkaline feldspars will being to melt at ambient pressure. Electrical conductivity measurements were obtained using the impedance spectroscopy method at temperatures between 300°C and 1100°C and the conductivity behaviour in labradorite determined upon melting. At least 800 ppm wt. uptake of water was measured in the crystal at saturated water conditions. The electrical conductivity in single crystal labradorite has been analysed using the Hashin and Shtrikman mixing model to determine the melt fraction and hydrous melt conductivity in the mineral. A preliminary version of this work was presented at GSA Cordilleran Section meeting July, 2017.
| Original language | English |
|---|---|
| Pages (from-to) | 388 |
| Number of pages | 1 |
| Journal | Geological Society of Australia Abstract |
| Issue number | 126 |
| Publication status | Published - 2018 |
| Event | XXII Meeting of the International Mineralogical Association - Melbourne Convention and Exhibition Centre, Melbourne, Australia Duration: 13 Aug 2018 → 17 Aug 2018 https://www.ima2018.com/ |