The Sand Dune Arch and Broken Arch Trail is a narrow path of sand and gravel amidst desert scrub leading to these Entrada Sandstone fins within Arches National Park. Sand Dune Arch is hidden between the towering rock slabs theoretically formed by subsidence, weathering, and erosion. According to an official pamphlet, geologists see circumstantial evidence that the Colorado Plateau was once a salt flat. Over millions of years flooding allowed sediment to build up and form a rock layer. As that sandstone is subjected to environmental stresses, blocks of rock erode. Many blocks simply disintegrate under the constant uneven stress but the "better balanced" blocks become arches.
focal length: 16mm | exposure: f/13 – 1/500 – ISO 250