I like the first one. Although I'm wondering about the colors in the shadow in the center. Whether the post process has washed out the texture a bit, regardless I like the bottom delta effect, the fact that the viewer really has to guess at scale, whether this is miniature or very large from a distance, and how the single rock at the bottom of the shadow looks like one of the wandering stones from la playa.
The second is good but for some reason doesn't speak to me personally nearly as much.