text: Colored regions on Jupiters satellite Europa are thought to be tholins. The morphology of Europas impact craters and ridges is suggestive of fluidized material welling up from the fractures where pyrolysis and radiolysis take place. In order to generate colored tholins on Europa there must be a source of materials (carbon, nitrogen, and water), and a source of energy to drive the reactions. Impurities in the water ice crust of Europa are presumed both to emerge from the interior as cryovolcanic events that resurface the body, and to accumulate from space as interplanetary dust.