No idea how to do what you're doing since I don't have the software but I do have one tiny thing to add - moraine. That's the pile of rubble at the end of a glacier. In terms of visualizing it, though, I wouldn't bother; it's just some stray rocks of varying size from pebbles to boulders and has no real affect on the terrain. It might be more fertile but that, too, is also not really worth trying to visualize since, if the glacier retreats, the land is still mostly tundra with thin tough grasses and sparse small shrubby trees or, at best, taiga with coniferous forests.