If these features are in fact related to an ancient ring structure formed by a large impact, their small curvature suggests that the original structure was even larger than one seen on Callisto. There is no apparent trace now of the center of this suggested structure, which must have been destroyed by the resurfacing evident over most of Ganymede in the grooved terrain. Another interpretation is that these features are not impact-related rings but are internally produced fractures crossing the dark terrain, similar to the grooved bands. It shows part of dark, densely cratered block which is bound on the south by lighter, and less cratered, grooved terrain. The dark blocks are believed to be the oldest parts of Ganymede's surface.
Numerous craters are visible, many with central peaks.
The large bright circular features have little relief and are probably the remnants of old, large craters that have been annealed by flow of the icy near-surface material. The closely-spaced arcuate, linear features are probably analogous to similar features on Ganymede which surround a large impact basin. The linear features here may indicate the former presence of a large impact basin to the southwest. Shown is a bright halo impact crater that shows the fresh material thrown out of the crater. In the background is bright grooved terrain that may be the result of shearing of the surface materials along fault planes.