An analysis of the mechanical behaviour of tectonically active icy satellite lithospheres through geological mapping, geomorphic analysis, and geophysical modeling

The research that has culminated in this thesis is an attempt to gain insight into a broad question. How do the lithospheres of tectonically active icy satellites behave? To accomplish this, geological mapping, geomorphic analysis, and geophysical modeling are used to explore the mechanical behavior of the lithospheres of the icy satellites Ganymede and Europa. For Ganymede, insights gained from the production of a global geologic map of the surface suggest that the lithosphere of this icy body has thickened with time and that the morphologies of possible plate boundaries suggest that the lithosphere responded nonrigidly to plate rotations. For Europa, geomorphic analysis of discontinuities associated with long linear structural features on the surface are used to suggest that the mechanical behavior of the lithosphere can be analogous to thin oceanic lithosphere on Earth. The kinematic analysis of triple junctions on Europa is used to suggest that plates on the icy satellite deform rigidly in an extensional environment. Geophysical modeling of plate motions on the surface of Europa are used to show that nonrigid plate deformation can occur in an extensional or compression environment. Finally, evidence is also found within these analyses supporting a formation mechanism for complex ridges on Europa involving the successive build-up of ridges over time and indicating that plate boundary reorganization might be an important factor affecting the evolution of long-lived features on Europa.