Ganymede and Callisto

摘要: The differences existing between Ganymede and Callisto are studied as well their volcanic, tectonic, impact surface processes. An attempt is made to explain the relatively vigorous history of geologic activity on apparent lack internal Callisto. Observations reveal that optical surfaces regoliths both bodies ice rich, thus unlikely be remnants a crust created by homogeneous accretion. Ganymede's clean mantle was source region for water, slush, or resurfaced more than half satellite; this resurfacing material structurally confined in broad rifts troughs often captured form grooved terrain. explanation tectonism its near total absence at least partially differentiated while undifferentiated.