Abstract

Paterae cover approximately 2% of the surface of Io, Jupiter’s volcanically active moon. To understand the formation of these volcano-tectonic depressions we created a geologic map of a key region and compared this map with experimental models for Io paterae. Our mapping region is Tupan Patera, a patera that has experienced recent activity and is a detected hot spot. We identified four primary types of geologic materials: plains, patera floors, flows, and diffuse deposits. We constructed an experimental model to test previous suggestions that paterae may form as volatiles in the silicate crust are vaporized by rising magma, creating instability, and subsequent collapse. The apparatus is a scaled model that uses sand (silicate crust analog), ice or snow (volatile analog), a hotplate (magma chamber analog), and a moveable paddle (to simulate extension). Our experimental collapse features exhibit many characteristics of paterae on Io, such as “islands,” terraces, straight margins, and steep scarps. Our model suggests that the role of volatiles in Io’s crust is a significant part of paterae formation.Comparative studies between our map and model show it is possible Tupan is an emerging lava lake or one in a state of quiescence. Our studies have also culminated in the completion of a theoretical cross section for the geologic history of Tupan Patera. This cross section displays a sequence of events including the rise of magma as it preferentially volatilizes sulfurous layers in the crust, subsequent thinning, instability, and collapse, the likelihood of the patera floor sinking as a stoped block, and the more recent flow and diffuse deposits. This study gives some insight to the general formation of paterae on Io.

Degree

College and Department

Physical and Mathematical Sciences; Geological Sciences

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