Bryce Canyon National Park & the Grand Staircase

Foos, Annabelle

This report describes the stratigraphy, structure, badlands formation and alluvial fan of Bryce Canyon National Park and the Grand Staircase. It includes figures, references, and exercises (questions, definitions).... The Grand Staircase is a series of cuestas that extend from the Kaibab Plateau, which forms the north rim of the Grand Canyon, northward to the Pink Cliffs of Bryce Canyon National Park (figures 1 and 2). In the high plateaus section, the stratigraphic units were tilted toward the north when the area was uplifted along north-south trending normal faults. Because of this northern dip the rocks become progressively younger going northward from the Grand Canyon, and the resistant beds form prominent cliffs or cuestas. On the drive between Bryce Canyon and the Grand Canyon we will stop at the Forest Service Lookout Area to get an overview of the Grand Staircase. The first series of low cuestas are the Chocolate Cliffs capped by resistant Triassic Shinarump Sandstone which occurs between the easily eroded Moenkopi and Chinle beds. The second series of cliffs are the Vermillion Cliffs held up by the Wingate Sandstone. The Jurassic Navajo sandstone which can be seen at Zion makes up the White Cliffs. The Gray Cliffs consist of Cretaceous shales and sandstones. Finally, the Pink Cliffs which top the Paunsaugunt Plateau are composed of the Tertiary Claron Formation which can be observed at Bryce Canyon.Introduction: The scenery at Bryce Canyon, with its unusual spires and hoodoos of colorful rocks, make it one of the most beautiful places on the Colorado Plateau. A descriptive Piute name for Bryce, Unka-timpe-wa-wince-pockich, means "red rocks standing like men in a bowl shaped Canyon" (Hirschmann, 1980). Bryce Canyon is located in the high plateaus section of the Colorado Plateau, on the eastern side of the Paunsaugunt Plateau, which is bounded to the west by the Sevier Fault and east by the Paunsaugunt Fault (figure 4). Headward erosion of the fault scarp by the Paria River and its tributaries has produced the spectacular scenery of the Paria Amphitheater. Elevations range from 6,300 feet near the town of Tropic to 9,300 feet near Crawford Pass. The rim of Bryce Canyon is a drainage divide that separates tributaries to the Sevier River, which drain west into the Great Basin, from tributaries of the Paria River, which drain east to the Colorado River and Gulf of California.