Reading the Grand Staircase: Five Cliffs, Two Hundred Million Years

The landscape around Kanab is part of one of the most extraordinary geological structures in North America. Geologists call it the Grand Staircase: a series of cliff-faced plateaus that step down from north to south, each one representing a different geological formation and a different age of deposition, each with its own color palette.

Starting at the top and moving south, the Pink Cliffs near Bryce Canyon are formed from the Claron Formation, a pale limestone that weathers into the delicate hoodoo spires Bryce is famous for. Below those, the Gray Cliffs, formed from Cretaceous shale and mudstone. Then the White Cliffs, the soaring walls of Navajo Sandstone that form the canyon walls of Zion National Park. Then the Vermilion Cliffs, colored deep red by iron oxide in the Moenave and Kayenta Formations. And finally, at the base, the Chocolate Cliffs, formed from an old Triassic layer, the Moenkopi Formation, colored by iron minerals, laid down on ancient tidal flats.

Kanab sits near the base of this staircase, in the canyon country where the Vermilion and Chocolate Cliffs converge. Standing in this valley, you are at the geological bottom of a structure that preserves more than two hundred million years of Earth history in a continuous rock record. The layers above Kanab span from Triassic tidal flats to Eocene lake sediments, stacked like the pages of a very slow book. The Western filmmakers who chose this landscape for its drama had no idea they were shooting in front of one of the longest windows into geological time anywhere on the continent.