I thought these might have been ready earlier tonight but testing a blend of two different scales of these cracks gave me a strange result(a big black shadow, being cast by nothing.) and I had to rework some things. I've fixed that now. Should have these done by tomorrow, if not tonight.*
They're by no means complicated function node work, like I've seen some of you mathematicians do wonders with in here before, I don't understand all that nonsense! Thick as sh*t!
The outline is the most rudimentary voronoi noise function, edited afterwards by your Friendly Neighbourhood Shader Nodes.
These are laid over a completely flat ground, no terrain nodes. Cracks are 10m scale:

And laid over a default terrain, POV = 50m Y:

And POV = 100m Y:

Lay them over any terrain to crack it up a bit. There will be different scaled shaders, too. See next post.
*EDIT: Upload folder is full, probably tomorrow then, if PS give us any more bandwidth to waste.