Dark Terrain on Ganymede: Geological Mapping and Interpretation of Galileo Regio at High Resolution

found on furrow and crater floors. We also find high albedo During its first two encounters with Ganymede, the Galileo units which include crater rims, furrow rims, and isolated knobs and massifs. Other features include an intermediate albedo spacecraft obtained images of a 16,500 km portion of Galileo Regio, a large expanse of dark terrain, at high resolution (76–86 lobate feature interpreted to be a palimpsest and a hummocky unit interpreted to be impact ejecta. Several processes are interm/pixel). Through mapping of the G1 and G2 target sites within Galileo Regio, we are able to characterize geological units based preted to have occurred within Galileo Regio. These include tectonic deformation, mass wasting, sublimation, resurfacing on their morphology and relative albedo. We find three generally low albedo units: an intermediate albedo plains unit, a by impact ejecta, and possibly cryovolcanism and isostatic adjustment. We observe that the NW–SE trending furrows lower albedo plains unit, and the lowest albedo unit which is