Cryovolcanism

Sites of cryovolcanisms on the surface, where this ammonia and water mixture reaches the surface, are possible locations for life that lives in liquid water but can tolerate ammonia.

Possible explanations include floods of liquid water, ice-based volcanic activity (termed cryovolcanism), or even some form of tectonic system. […] Voyager also found evidence of cryovolcanism on Neptune's moon Triton.