Neutrino:
The planet archetype spec defines how the different biomes interact on a particular planet. So if you want to create a volcano/ice planet make one with those biomes and give it the right settings.
Basically a biome is simply saying "this area is this type of terrain". A planet archetype defines how the biomes related to one another. So by combinging biomes differently in different archetypes you can make different kinds of planets.