Hmm....that is interesting. In my amaturish opinion I would say that the southern hemispher of Mars is more of a mountainish region than the nothern
hemisphere. But I have no idea.
I don't know, but I understand Mars is mostly iron oxide. Iron oxide (rust) goes through phase changes and occurs in many colors: black, blue,
yellow, red, orange... You can see this on rusty iron, blue gun barrels, the artist's pigments
Mars Yellow, Mars Black, Mars red and so on.