Two basic volcanic processes take place on Earth. I know its a lot more complicated than that but bear with me.
Surface ejections of volatiles are light colored. Deep ejections of particles are dark colored. This is a generalization not an absolute. The color of the material ejected can indicate the degree of energy required to expel the material. |
Jupiter's closest Galilean moon Io, experiences a high degree of tidal flexing energy such that it has boiled away all the water and has turned Io's rock into a molten ball.
While Io's surface is cold, hot molten rock and sulfur is regularly spilled onto its cold surface. Io's rocky core is heated enough to boil rock depositing dark minerals onto its surface. Minerals are ejected from deep within the planet onto the sulfur rich surface leaving dark streaks and patches. The tidal flex energy experienced on Io is massive and its enough to frequently push heavy minerals from deep inside the moon onto its surface creating dark spots. When there is dark sooty material on rocky surfaces the tidal flex energy is very high. |
Update Dec 1, 2017 Cassini flew past Europa in 2014 then again in 2016 and detected a plume of water ejecting from the same location. Cassini's cosmic dust analyzer revealed there were silicon dioxide grains in the plumes, indicating warm hydrothermal activity. There are minerals getting ejected out of these plumes. |
This is Enceladus a Saturn moon which is tidally flexed enough to form cracks on its icy surface from which water ices erupt and spew outward into space and onto its surface.
There is no dark material associated with these eruptions so minerals from below are not erupting onto the surface only light volatile gasses. |
When there's nothing but volatile white ices on top of an icy surface tidal flex energy is low.
Below- thick rugged ice crust terrain of Enceladus |
Wiki quote
Much of Enceladus' surface is covered with craters at various densities and levels of degradation. This subdivision of cratered terrains on the basis of crater density (and thus surface age) suggests that Enceladus has been resurfaced in multiple stages. The heavily cratered surface indicates the outer crust ice layer is thick in turn retaining its rough terrain shape and impact craters. This means the tidal flex energy is enough to crack the surface and warm the rocky interior such that there is a subsurface ocean but not enough to force heavier minerals from deep inside onto the surface or to create a thin ice crust. |
Triton is in a near perfect circular orbit with Neptune as Pluto is with Charon but both show signs of current activity. Triton is a Neptune captured Kuiper belt object which is very similar to Pluto (its twin) in composition, size, density and surface temperature but it has significantly more tidal flex energy than Pluto which is displayed on their surfaces. |
Some surface features on Triton look like impact sites.
It appears as though something hit Triton in these locations and simply got swallowed. The warmer subsurface ices then flowed into the hole back filling and smoothing the surface around the impact site. These images demonstrate how thin the ice crust must be or stated another way, these images show how hot the interior is to sustain such a thin crust under such extremely cold external conditions. |
This is an artists rendition of what these eruptions might look like on Triton.
Since Triton is composed mostly of the same stuff as Pluto one would expect to see red tholin on the surface of Triton as depicted in this image but there isn't any. This suggests tholin is heavier than the surface volatiles and it sunk inward during the Triton capture event. The surface is mostly crater free. Triton's surface temperature is 38K and yet internal tidal flex energy from its mantle has erased almost all evidence of impacts. Nearly all of Triton's surface has been recently resurfaced and yet it has black soot streaks from eruptions on the surface making this a very active energetic moon. Triton is currently active, billowing out dark dust from deep inside displaying signs of strong tidal flex energy. |
Sputnik Planitia shows a clear boundary line color change along its eastern edge where runoff fluid from the highlands flows onto and then mingles with the pinkish colored fluid in the SP basin.
The flowing gray material to the east is almost certainly created by adiabatic condensation of Pluto's fog. As the fog rises in elevation it is cooled and condensed coating the surface with wet nitrogen forming lakes scattered throughout this area. The runoff is gray suggesting this is the color you get from this surface mixing process. |
The twisting torque felt on both Pluto and Charon with their axis wobble of 24 degrees every 1.4 million years would likely be sufficient to cause this effect.
If this twisting torque caused the interior and exterior spheres to slip over each becoming mechanically decoupled additional energy would be imparted. This decoupling causes a phenomenon called true polar wonder. |
This Pluto skin slip is similar to how the Hawaiian Islands are riding on a tectonic plate slipping over a hot spot in the Pacific ocean.
Pluto's hot spot at SP is obviously stabilized by Charon's gravitational bulge focus at this location. Imagine the bulging swelling ocean tides our moon creates on Earth. This is what Charon does at this location of SP then imagine both planets wobbling 24 degrees back and forth gravitationally twisting and torquing on each other. The tidal bulge is oscillated back and forth at SP warming the nitrogen creating this hot spot. |
Educated men will look at the work I do and and say that it is useless work, but the words they breath from their mouths are as wise as the wind they fart from their ass.
Fools! Knowledge begins with sensation, with experience, it does not begin with the study of Latin, I will have none of that. I say that knowledge begins with love. Nature must be our guide, if you look anywhere but nature you're wasting your time. Nature begins with a cause and ends with an experience. So begin with the experience and investigate the cause. Leonardo da Vinci |