Grooves on Ganymede have been interpreted as fractures that result from extensional tectonics which, accompanied by some type of resurfacing, changed relatively low-albedo, heavily cratered terrain to higher-albedo, less cratered grooved terrain. The formation of grooves involved initial fracturing of cratered terrain, resurfacing confined within these fractures, and subsequent fracturing of resurfacing material. Crosscutting and terminating, or ''T'' structural relationships among grooves, groove sets, and cratered terrain indicate that grooved terrain developed in three stages. The formation of primary grooves marks the initial breakup of cratered terrain. Secondary grooves generally terminate against primary grooves and complete the breakup of cratered terrain into polygons that are mechanically isolated from adjacent polygons. In the final state (3), polygons of cratered terrain are fractured, resurfaced, and the resurfacing material is subsequently fractured by a set of closely spaced, parallel to subparallel grooves that terminate against the older primary and/or secondary grooves. In each of these stages, the groove-forming process occurs in the same sequence: fracturing, resurfacing, and subsequent fracturing of resurfacing material, but most of the area of grooved terrain is resurfaced during stage 3. The process may stop during any of the three stages yielding areas of fractured cratered terrain, polygons of cratered terrain, polygons which have been resurfaced but not subsequently fractured (smooth terrain), or completely grooved terrain. Regardless of place or time of development, grooved terrain appears to have evolved according to the same sequential order of stages. Because the development of grooves within each stage created smaller isolated polygons out of larger areas, this process has resulted in the break-up of the surface of Ganymede into progressively smaller and more equidimensional mechanical units.