Io AGU Abstracts

Abstracts for the AGU Fall Meeting are now online. This now gives us a chance to look at some of the Io-related talks and posters to be presented at the December meeting:

• Dave Williams will give a talk on December 19 titled, "Volcanism on Io: Insights from Global Geologic Mapping." Williams will describe work his group performed on a new global geologic map of Io that uses a new USGS global mosaic. Geologic maps for other planetary bodies define different morphologic features on the surface, as opposed to terrestrial geologic maps which are ususally based on the mapping of different rock layers. One interesting conclusion they make is that bright lava flows cover more of the surface than dark flows, with some bright flows not being adjacent to dark flows, suggestive of primary sulfur volcanism at some locations. I should point out that many dark flows turn bright over time (like Thor).
• Windy Jaeger will present a poster on December 18 titled, "Lithospheric Structure and Patera Formation on Io: Implications for Future Observations." As the title suggests, the poster will present how the structure of the lithosphere may influence the formation of volcanic depressions on Io. Jaeger's lithosphere model suggests that the upper few kilometers of the lithosphere consists of interbedded layers of SO₂ and cooled silicate lava flows. Below this, silicates dominate with fewer volatiles. When magma rises to the surface, it stalls when it reaches the interface between these two sections, forming sills. These sills then sublimate the SO₂ above it, the new void forming a depression, a patera. Jaeger suggests that this model could be tested by future spacecraft by acquiring high-resolution images of patera and mountain flanks, as well as medium-resolution stereo observations acquired over a period of at least a year.
• Ashley Davies suggests, in his abstract "Using Lava Tube Skylight Thermal Emission Spectra to Determine Lava Composition on Io: Quantitative Constraints for Observations by Future Missions to the Jovian System," that observing holes (known as skylights) over active lava tubes. Lava tubes keep erupted magma mobile by insulating it, generally maintaining the lava at temperatures close to the eruption temperature. This temperature would provide an an important constraint on composition.
• In "Lava Fountains on Io: Implications for the Interior and Future Observations," Laszlo Keszthelyi looks at the same problem from a different approach. He suggests that imaging lava fountains would be useful for determining Io's lava composition. To accomplish this, data would need to be acquired over multiple filters over a very short period of time, likely less than 0.1 seconds. The camera system planned for the Io Volcanic Observer would image Io in four filters simultaneously for this very reason.
• Julie Rathbun will present a poster titled, "Io from Ground-based Eclipse Observations: Implications for the Eruptive History of Loki." This appears to cover the same territory as the talk she gave at DPS.