Physical Models of Tectonic Resurfacing on Ganymede

Introduction: Grooved terrain on Ganymede generally occurs as individual lanes and polygonal crosscutting swaths of bright terrain. Internally, grooved terrain swaths consist of parallel to sub-parallel ridges and troughs at a variety of scales (Fig. 1); the ridges and troughs show generally similar morphology, size, and orientation. Grooved terrain on Ganymede has been interpreted by most authors as the product of fault-accommodated, distributed crustal extension, possibly accompanied by cryovolcanism [1-4]. It is generally postulated that Ganymede’s lithosphere is composed of an icy ductile horizon beneath a thin (~2 km), brittle, upper lithosphere of predominantly water ice. Fault scarps in the uppermost crust are clearly observable in images of Ganymede’s surface, indicating that the uppermost crust deforms as brittle material.