Almost appears as an out flowing of material from a large impact at lower half.
I’m thinking that all these large feaures are primordial, reflecting the origins of the Pluto system in some kind of complex collision, probably with follow-up collisions over the course of some millions of years, but all transpiring some few billions of years ago.
It does, probably is. Despite its small size relative to the rest of the planets, and its somewhat lower density than the other four rocky planets (Mercury, Venus, Earth, Mars), Pluto’s out by itself and better able to capture new satellites. The view that Pluto-Charon was formed in an impact event is the more popular explanation for Charon’s origin.