T305 Voyager to New Horizons and Beyond: Exploring the Icy Worlds of the Outer Solar System

Wednesday, 30 October 2013
8:00 AM - 12:00 PM
Room 201

A SHALLOW SUBSURFACE HYDROLOGIC SYSTEM ON EUROPA?

Paper number: T305-11
Program: Technical Sessions
Time: 10:40 AM – 11:00 AM

Authors

Abstract

Europa’s chaos terrains may derive from the collapse of the ice above shallow perched water lenses formed by melting of the upper ice shell by ascending thermo-compositional plumes. New arguments suggest that the process of chaos formation is analogous to the collapse of terrestrial ice shelves in which massive ice bodies disintegrate on short timescales, capsizing ice and possibly violently mixing the subsurface. Thera and Thrace Macula are two closely spaced chaos features on Europa’s anti-jovian hemisphere characterized by dark coloration and the appearance of disaggregated ice as well as “swollen” and “embayed” morphologies. Hydraulic direction of subsurface water provides a means to explain these features, as a consequence of the formation and evolution of putative water bodies beneath chaos terrain.

We used COMSOL to model the present-day hydraulic conditions that would occur at both Thrace and Thera Macula were a subsurface water volume to exist. We use Galileo data to provide the approximate heights of the high and low-lying terrain, and the water depths, volumes, and ice properties described by Schmidt et al. (2011) to calculate the models.

These analyses show evidence for shallow water mobility within Europa’s crust, which bolsters the case for a presently active Europa with abundant shallow water. Using our models we place constraints on water flow and the material properties of the ice. We show that this system is governed by surface topography that determines subsurface hydraulic potential and that may create subsurface pathways for hydraulic connectivity between shallow environments. Our results imply that the habitability of Europa may be coupled to subsurface hydrological systems that can be characterized by future ice penetrating radar exploration of Europa.