This image evolved as a result of playing around with terrains. The sky, which gives the scene its character, was produced by clicking the 'Random' button and only slightly modified subsequently.
The whiteish glaze on the rocks in the foreground - frost? mineral deposits? - at the right was produced by duplicating the terrain, increasing its size slightly, and applying a fog texture to it. It didn't give quite the effect I expected, but it seems to fit with the scene.