Is it possible to add terrain features on top of Martian Ironearth?

I kept things very simple when basing my models: I just primed the bases with Mephiston Red, then lathered on Martian Ironearth for that dry, cracked earth look. I've now come to find it a bit plain, and I'm wondering if I can add skulls on top of it. But the paint looks pretty loose, what with all those cracks. Is there any point in trying to glue skulls onto technical paints?