Geology – Bryce Canyon – Grand Staircase

The Grand Staircase Escalante National Monument includes 1.9 million acres of rugged and remote landscape from Escalante to Kanab.

The vast monument is divided into three geographically distinct regions consisting of the oldest layers in the southern Grand Staircase section, the central region known as the Kaiparowits Basin, and the northern Escalante Canyons region.

Perhaps most intriguing about Grand Staircase Escalante National Monument is its layered ‘staircase’ effect which reveals a stunning geologic history spanning at least 275 million years. The layers of sedimentary rock that create the Grand Staircase were revealed when the area now known as the Colorado Plateau uplifted about two miles during the Laramide orogeny, a mountain-building event that occurred 75 million years ago. The sedimentary layers are the results of millions of years of changing climate and landscape. Variations in the rate of erosion for different hard and soft rock types, such as Dakota and Tropic shale, limestone, and Navajo sandstone, have formed the cliffs, mountains, and plateaus of the Grand Staircase that we see today.

The Chocolate Cliffs, formed during the Moenkopi Formation about 240 million years ago, are the oldest layers and are exposed in the Grand Staircase Section near the Utah/Arizona border, while the geologically youngest Pink Cliffs are exposed to the north in the Escalante Canyons section. The layers in between—the Vermillion, White, and Gray Cliffs—reveal a geologic timeline spanning about 200 million years, from the Permian to the Cretaceous periods. This fossil-rich area makes up the Kaiparowits Basin. The Grand Staircase section of the monument includes the Kaibab Plateau which forms the North Rim of the Grand Canyon and features cliffs that rise up to 2,000 feet. The Pink Cliffs of the Grand Staircase, created during the Claron Formation, can be seen in Bryce Canyon National Park and throughout Bryce Canyon Country.

Bryce Canyon’s geologic history begins around the Cretaceous Period, when a shallow sea covered the region. The sea, and the lakes, streams, and deserts that came later, deposited layers of silt, shale and sandstone. The landscape was further defined by earthquakes, volcano eruptions, and other forces of nature. Sediment from these ancient waterways is visible in Bryce Canyon’s hoodoos, which are largely composed of limestone. These alternating soft and hard rock layers have been further eroded by the forces of ice, wind, and water, which constantly change the shape of Bryce Canyon’s incredible 60-million-year-old hoodoos.

Geologist Clarence Dutton is credited with defining the layers of the Grand Staircase in 1870. The area became a National Monument in 1996 under President Bill Clinton and is managed by the U.S. Bureau of Land Management (BLM).

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