A clathrate reservoir hypothesis for Enceladus' south polar plume.

We hypothesize that active tectonic processes in the south polar terrain of Enceladus, the 500-kilometer-diameter moon of Saturn, are creating fractures that cause degassing of a clathrate reservoir to produce the plume documented by the instruments on the Cassini spacecraft. Advection of gas and ice transports energy, supplied at depth as latent heat of clathrate decomposition, to shallower levels, where it reappears as latent heat of condensation of ice. The plume itself, which has a discharge rate comparable to Old Faithful Geyser in Yellowstone National Park, probably represents small leaks from this massive advective system.