Portals
Cliff detail, Grand Canyon, a few miles downstream from Redwall Cavern. My guess is that the dark-colored layer at the bottom is the top of the Muav limestone, evidently a much less permeable layer than the more porous Redwall limestone above. When the water in the Redwall channels reaches the bottom, it has to go somewhere, and these portals provide an outlet. Whether this is the boundary between Muav and Redwall, these two formations are separated in time by 65 million years--an "unconformity".
I like how the cliff on the right slants in a different direction. This gives a stronger 3D effect to the shot.
Portals
Cliff detail, Grand Canyon, a few miles downstream from Redwall Cavern. My guess is that the dark-colored layer at the bottom is the top of the Muav limestone, evidently a much less permeable layer than the more porous Redwall limestone above. When the water in the Redwall channels reaches the bottom, it has to go somewhere, and these portals provide an outlet. Whether this is the boundary between Muav and Redwall, these two formations are separated in time by 65 million years--an "unconformity".
I like how the cliff on the right slants in a different direction. This gives a stronger 3D effect to the shot.