Combining Laboratory Measurements with Electromagnetic Observations to Probe the Interior of the Earth and other Terrestrial Bodies
Abstract
This presentation will review past efforts and present frontier perspectives to further our understanding of the Earth's mantle structure and other planetary interiors using field and laboratory electrical measurements. The combination of laboratory-based electrical models (using impedance spectroscopy) and field observations (from electromagnetic measurements) is key to improving our knowledge of the thermal and mineralogical structure of the Earth's interior. This approach has also been applied to other terrestrial bodies such as the Moon, Mercury, the Galilean satellites and could be used to investigate other planetary worlds.
Electrical conductivity, being very sensitive to changes in temperature and chemistry, has proven successful at imaging interconnected melts and aqueous fluids in different geological settings. In particular, several field and laboratory conductivity studies of mid-ocean ridges and subduction zones have contributed to our understanding of melt migration pathways and volatiles cycles in the Earth's upper mantle, though the interpretation of field anomalies is a highly nonlinear and complex problem. The current dataset of electrical laboratory studies covers a large variety of Earth materials, therefore offering more sophisticated and realistic ways to interpret field observations in terms of composition, texture, and temperature than what was previously achievable. For instance, recent electrical anisotropy studies have investigated the structure of the asthenosphere, explaining field observations at this depth in terms of localized rock deformation, possibly with the presence of melt. The electromagnetic technique has also been used together with laboratory measurements to study the interior of other terrestrial bodies, being therefore a relevant technique to deploy as part of ongoing and future spacecraft missions. Considering conductivity-temperature relationships, electromagnetic sounding has been used to derive temperature profiles inside these bodies as well as defining plausible mineralogies. Recent examples of planetary applications will be highlighted, including studies that have led to infer the presence of a subsurface water ocean in Ganymede, a magma ocean in Io, and to place limits on the size of the metallic core of the Moon and Mercury.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGP11A..02P
- Keywords:
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- 0925 Magnetic and electrical methods;
- EXPLORATION GEOPHYSICS;
- 1515 Geomagnetic induction;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 3006 Marine electromagnetics;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3914 Electrical properties;
- MINERAL PHYSICS