A Potential Mushy Source for the Geysers of Enceladus and Other Icy Satellites

Meyer, Colin R.; Buffo, Jacob J.; Nimmo, Francis; Wells, Andrew J.; Boury, Samuel; Fox‐Powell, Mark; Tomlinson, Tara C.; Parkinson, Jamie R. G. and Vasil, Geoffrey M. (2025). A Potential Mushy Source for the Geysers of Enceladus and Other Icy Satellites. Geophysical Research Letters, 52(3), article no. e2024GL111929.

DOI: https://doi.org/10.1029/2024gl111929

Abstract

Enceladus is a target for astrobiology due to the H₂O plume ejecta measured by the Cassini spacecraft and the inferred subsurface ocean that could be the source of the geysers. Here we explore an alternative where shear heating along tiger stripe fractures produces partial melting in the ice shell and interstitial convection allows fluid to be ejected as geysers. We use an idealized two‐dimensional reactive transport model to simulate a mushy region generated by an upper‐bound estimate for the localized shear heating rate. We find that the rate of internal melting could potentially match the observed eruption rate. The composition of the liquid brine would be, however, distinct from that of the ocean, due to fractionation during partial melting. This shear heating mechanism for geyser formation could apply to Enceladus and other icy moons and has implications for our understanding of the geophysical processes and astrobiological potential of icy satellites.