Created in Blender using shader nodes and some image textures.
I was following along with one of Jan Urschel`s tutorials on Creating Procedural landscapes
so check that out if you wish to learn more.
https://www.artstation.com/artwork/EV84rA
This is an interesting alternative to working with traditional polygon modeling and when combined with other workflows can yield interesting results.
A great project to feed a hungry computer when you find yourself locked indoors and missing nature.