Jeff, thanks for taking time to tips you shared while taking these pictures. I'm convinced that I need to buy a more solid tripod than the light-weight one I have now, so that I can get some absolutely crisp longer exposures and bring out more of the tonality. I put several of mine from this day in a book (on Blurb) documenting my godson's and my vacation. But these pictures of yours are on a whole 'nother level. Well done! I especially like this picture, shot straight up.
By the way, I agree with your suggestion to take more than one camera, each with different lenses, when shooting in these slot canyons, because there is indeed dust and sand in the air.