HR: 1340h
AN: P53B-1246    [Abstracts]
TI: Terrestrial Diapirs as Analogs to Europa's Lenticulae and Chaos, and Implications for Europa Exploration
AU: * Pappalardo, R T
EM: robert.pappalardo@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, United States
AB: Ice diapirism has been cited to explain Europa's pits, spots, and domes (commonly collectively referred to as "lenticulae") as well as the satellite's larger chaos terrains. Europa's diapirs have been modeled as thermal- compositional in origin, rising within an ice shell greater than ~20 km thick. The morphologies and characteristics of terrestrial diapirs shed light on possible diapiric processes within Europa. Diapirs commonly rise in fields of similarly sized subcircular features which can intrude into the shallow subsurface or extrude onto the surface. Rim synclines (peripheral depressions) may form in response to withdrawal of diapiric material from a diapir's surroundings, and peripheral and crestal faults are predicted above intrusive diapirs. The heads of neighboring synchronously active diapirs can flatten against one another. Each of these terrestrial characteristics is consistent with the morphologies of some Europan lenticulae. Terrestrial diapiric heads can merge into a broad canopy, potentially analogous to the formation of some Europan chaos terrains. Xenoliths can be carried upward within terrestrial diapirs, suggesting that diapirism within Europa's ice shell can dredge deep material up toward the surface on the timescale of diapir rise. The deepest strata rise into the central axes of terrestrial diapirs, implying that materials from greatest depth in Europa's ice shell may be exposed in the centers of individual extrusive lenticulae and in discrete locations within chaos regions. Lenticulae and chaos are high priority locations to explore for materials that have risen from near Europa's ice-ocean interface to the surface.
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
DE: 6218 Jovian satellites
DE: 8003 Diapir and diapirism
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting