FORMATION OF EUROPAN RIDGES BY INCREMENTAL ICE WEDGING

Double ridges are one of the most ubiquitous surface features on Europa. Double ridges are pairs of linear topographic highs on the order of 100 m in topographic relief that are divided by a narrow trough. The double ridges are narrow, with widths less than 5 km. They span 100s of km, overlap with one another, and cover much of Europa’s surface. The ubiquity of double ridges implies that the process forming them can occur globally rather than in a single region with unusual properties. Constraining the formation of ridges may provide constraints on possible shell thicknesses and thermomechanical states globally on Europa. However, the mechanism responsible for ridge formation is still uncertain. This thesis discusses tests of the viability of incremental ice wedging to create topography like that observed at Europa’s ridges through finite element modeling. This work also narrows the range of depths at which a wedge could create a double ridge. The results indicate that shallow wedges less than 500 m from the surface can create deformation similar to observed double ridges.