In the southern area east of SP the material is practically all blue with the exception of where we see these conically shaped holes.
Again, this seems to imply tholin is being vented from below the surface and onto the landscape. This tholin is different from what exist west and north of SP.
While the blue liquid seems to form from the nitrogen rich atmosphere it apparently takes more time for the blue fluid to form than it takes the tholin rich gasses that spew out of these conically shaped holes to spread on top of the blue stuff.
As much as it pains me to say it, this could be considered cryovolcanism but this scene looks different than the theoretical volcanoes on the south pole area.
Here we can see how the tholin has been sprayed around on the surface, discoloring the surrounding landscape.