ARC-1979-AC79-7089

P-21761 C Range: 313,000 kilometers (194,000 miles) This color reconstruction of part of the northern hemisphere of Ganymede shows a scene approximately 1,300 kilometers (806 miles) across. 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 similiar 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.