Today's Colorado Plateau was once at the bottom of a shallow ocean basin that cut North America into a western and eastern half about 92 million years ago. This resulted in the deposition of multiple layers of marine sediments, and later freshwater sediments, that became compressed into the distinct layers of sandstone, siltstone and mudstone that can be seen in the eroded geological features found on the Colorado Plateau today.
These exposed layers of ancient marine and freshwater sediment were dubbed the "Grand Staircase" by geologist and army officer Clarence Dutton in the early 1880s after reaching the north rim of the Grand Canyon by crossing the high plateaus of southern Utah. He was the first geologist to make the evolutionary connection between the exposed layers in places like Zion and Bryce Canyon and the layers exposed in the walls of the Grand Canyon of the Colorado River.
Having been laid down between 20 million and 200 million years ago, the layers exposed in Bryce Canyon, as seen in this week's photo, are at the very top of the Grand Staircase with the layers seen at the bottom of the Grand Canyon at the very bottom.
In a sense, Bryce Canyon can be considered as the uppermost rim of the Grand Canyon. The layers exposed in Bryce Canyon are known as the Pink Cliffs of the Grand Staircase and are eroded from the Claron Formation that was deposited within the last 65 million years. The colors we see today reflect the conditions under which the original sediments were deposited. Reds and oranges indicate that oxygen was present to oxidize iron. The white layers near the top are composed of limestone deposited as calcite crystals in freshwater lakes that covered the area. Limestone is white because it contains little to no iron.
This week's photo was taken with a Canon 5D MkIII dSLR and an EF 85 mm f/1.2 lens. Exposure was for 1/750 sec at f/8.0 with an ISO of 400.