Effects of Composition, Melt, and Fluids on Electrical Resistivity With Application to Magnetotelluric Investigations
Abstract
We use recent laboratory conductivity models combined with petrologic models to develop a procedure for systematically estimating the contributions of composition, melt, and fluids to electrical resistivity observations of the Earth's mantle. We apply this method to 3-D inversions of EarthScope magnetotelluric (MT) data, Hawaiian SWELL experiment, and a 400 km long Colorado Plateau--Basin and Range MT line. Preliminary results suggest that significant anisotropy cannot result from alignment of the olivine a-axis under anhydrous or hydrous conditions but must result from structural anisotropy such as a preferred orientation to melt interconnectivity. In some cases, independent estimates of the geotherm may be necessary for a proper interpretation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMDI31B..07H
- Keywords:
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- 8124 TECTONOPHYSICS / Earth's interior: composition and state;
- 0925 EXPLORATION GEOPHYSICS / Magnetic and electrical methods;
- 3621 MINERALOGY AND PETROLOGY / Mantle processes;
- 3914 MINERAL PHYSICS / Electrical properties