When heated, their black soil sinks and liquid water frozen on the surface creates a bright icy body. The volcanoes erupt molten sulfur that turns black to red in color as it cools. Tidal forces from Jupiter and the other outer moons keep pulling and stretching on it, creating frictional heating. These tidal forces drove off all the ices from its surface. Modest tidal flexing heats the interior and melts the ice, and the surface has grooves and craters from this.
Water erupts to the surface and freezes into an iced layer, hiding the original crust.
Young crust maybe 60 miles thick ice overlaying a liquid water ocean. Good recipe for life. It has thin polar caps of water frost, and a negligible atmosphere. There is bright and dark surface area, with the dark terrain older, and more cratered. It must have more ice than soil , and this also implies the least heating , so that the ice is not driven off, leaving only soil behind.